Stainless steel clad steel sheet for bridge structures and method for manufacturing the same

Abstract

This invention discloses a stainless steel clad steel plate for bridge structures and a method for manufacturing the same. In the above method, the plate is assembled using an upper carbon steel material A, a lower carbon steel material B, at least two stainless steel clad materials as an intermediate layer, and four sealing materials surrounding the four sides of the intermediate layer. Circular through holes are provided in the sealing materials, and steel pipes are welded into the through holes. A cavity is left around the steel pipes during build-up welding. After vacuum drawing, the steel pipes are folded into the remaining cavity, and then welded to seal the steel pipes within the cavity. The first n passes in the entire rolling process are widthwise rolling, followed by longitudinal rolling. After the nth pass and after the n+2th pass, the material is water-cooled once in a reciprocating motion using six sets of headers.

Description

[Technical Field]

[0001] This invention relates to stainless steel clad steel sheets for bridge structures and a method for manufacturing the same, and belongs to the field of steel material manufacturing technology. [Background technology]

[0002] With the continuous development of science, technology, and industry, ordinary alloy sheets have become insufficient to meet the overall performance requirements of materials in industrial development, leading to the creation of clad steel sheets in response to the demands of the times. Stainless steel clad steel sheets are composite materials in which carbon steel or low-alloy steel forms the base layer and stainless steel forms the clad layer, with the base layer and clad layer being metallurgically bonded together. Stainless steel clad steel sheets not only possess the corrosion resistance of the stainless steel clad layer, but also the excellent mechanical performance and price advantage of the carbon steel or low-alloy steel base layer, making them one of the important development directions for steel materials.

[0003] In recent years, with the increasing demand for safety and long lifespan in steel bridges, the problem of rust and corrosion prevention in steel bridge structures has become more pronounced. By coating the surface of bridge steel materials with a corrosion-resistant protective material layer and using it instead of a single bridge steel plate, it is possible to achieve long-term corrosion prevention targets that cannot be achieved with painting methods. For this reason, stainless steel clad steel plates have become a relatively ideal option. However, due to limitations in manufacturing technology, conventional stainless steel clad steel plates have defects such as poor shape, poor surface quality, poor interfacial bonding quality, difficulty in welding during use, and insufficient weld strength. Furthermore, the manufacturing process itself has problems such as significant environmental pollution, difficulty in manufacturing, low production efficiency, and low yield.

[0004] Specifically, current manufacturing technologies for stainless steel clad sheets are divided into two types: explosive bonding and rolling bonding.

[0005] Regarding manufacturing technology using explosive bonding, for example, in the Chinese patent application with publication number CN110064835A, the bonding of the base material and cladding material is achieved by an explosive bonding method. However, on the one hand, the explosion causes vibration, noise, and dust pollution to the environment, and on the other hand, cladding steel sheets manufactured by the explosive bonding method have relatively inferior shape and surface quality.

[0006] Manufacturing technologies using rolling bonding have problems such as difficulty in processing, low production efficiency, and low yield. For example, there is a grooved material manufacturing technology used in the Chinese patent application with publication number CN107009090A. Furthermore, some technologies have problems such as poor interfacial bonding and poor surface quality. For example, in the Chinese patent application with publication number CN109694986A, the stainless steel clad material layer is exposed, making it difficult to ensure the surface quality of the sides of the stainless steel clad material layer. In addition, the aluminum strips tend to fall off during the transport process of the composite material, causing air leakage and affecting the interfacial bonding quality. Moreover, the influence of the rolling process on interfacial bonding quality, particularly a method that considers interfacial bonding quality while guaranteeing the performance of both the base material layer and the clad material layer, has not been disclosed in the prior art. [Overview of the Initiative]

[0007] The object of the present invention is to provide a stainless steel clad sheet for bridge structures and a method for manufacturing the same in order to solve at least one technical problem raised in the background art.

[0008] To achieve the object of the above invention, one embodiment of the present invention provides a method for manufacturing stainless steel clad steel sheets for bridge structures. The method includes the steps of material preparation, release agent application, assembly, seal welding, vacuuming, sealing, heating, rolling, cooling, cutting, and flattening. In the assembly process, the assembly is carried out using an upper carbon steel material A, a lower carbon steel material B, at least two stainless steel clad materials as an intermediate layer, and four sealing materials surrounding the four sides of the intermediate layer. Gas shield welding is performed between the sealing materials and material A, and between the sealing materials and material B to form a material assembly. A groove with a depth D is formed on all four sides of the material assembly, surrounded by material A, the sealing materials, and material B. A circular through-hole is provided in the sealing material on one side of the material assembly, and a steel pipe with an outer diameter r is welded to this through-hole. In the seal welding process, build-up welding is performed on the groove, leaving a cavity with radius R>r concentric with the steel pipe around the steel pipe during build-up welding, and when the penetration depth of the groove on the side where the steel pipe is positioned reaches 2 / 3 of the groove depth, and the penetration depth of the groove on the other side exceeds 2 / 3 of the groove depth, build-up welding is stopped. In the sealing process, after the vacuuming process of the material assembly is completed, the steel pipe is heated with a torch, flattened, and folded into the remaining cavity, and then the cavity is welded by gas shield welding to seal the steel pipe inside the cavity, and then build-up welding is continued until the groove is filled, and finally surface welding is performed to obtain the clad material assembly. In the rolling process, the clad material assembly coming out of the heating furnace is rolled to produce a large clad steel sheet. The first n passes of the entire rolling process are widthwise rolling, and from the (n+1)th pass onward, longitudinal rolling is employed. The reduction amount of the first pass is 25 mm or more, and the rolling temperature is 1060°C or higher. The width of the material after the nth pass is Wt + (0~40) mm, where Wt is the target width of the large clad steel sheet. The rolling temperature of the nth pass is 1030°C or higher. Between the nth pass and the (n+1)th pass, and between the (n+2)th pass and the (n+3)th pass, the material is water-cooled once in a reciprocating motion using six sets of headers, with a cooling water volume of 120~180 m³ in the upper header of each set of headers. 3 / h, the cooling water volume in the lower header is 160-220m 3The rolling speed is 0.8 to 1.2 m / s, the reduction amount from the (n+1)th pass to the (n+3)th pass is 40 mm or more, the rolling temperature of the (n+1)th pass is 950°C or higher, in the mth pass the rolling temperature is 900°C or higher and the material is rolled until the material thickness is 2.5 to 3.5 times the target thickness of the clad steel sheet, then water cooling is performed and the material is cooled until the surface temperature is 840°C or lower, then the second stage of rolling is performed and the material thickness is rolled until the material thickness is the target thickness of the clad steel sheet to complete the entire rolling process, the rolling temperature of the first pass of the second stage of rolling is 810°C to 840°C and the rolling temperature of the final pass is 780 to 810°C.

[0009] To achieve the object of the above invention, one embodiment of the present invention provides a stainless clad steel sheet for bridge structures. The manufacturing method includes the steps of material preparation, mold release agent application, assembly, seal welding, vacuum drawing, sealing, heating, rolling, cooling, cutting, and flattening. In the assembly process, the assembly is carried out using an upper carbon steel material A, a lower carbon steel material B, at least two stainless steel clad materials as an intermediate layer, and four sealing materials surrounding the four sides of the intermediate layer. Gas shield welding is performed between the sealing materials and material A, and between the sealing materials and material B to form a material assembly. A groove with a depth D is formed on all four sides of the material assembly, surrounded by material A, the sealing materials, and material B. A circular through-hole is provided in the sealing material on one side of the material assembly, and a steel pipe with an outer diameter r is welded to this through-hole. In the seal welding process, build-up welding is performed on the groove, leaving a cavity with radius R>r concentric with the steel pipe around the steel pipe during build-up welding, and when the penetration depth of the groove on the side where the steel pipe is positioned reaches 2 / 3 of the groove depth, and the penetration depth of the groove on the other side exceeds 2 / 3 of the groove depth, build-up welding is stopped. In the sealing process, after the vacuuming process of the material assembly is completed, the steel pipe is heated with a torch, flattened, and folded into the remaining cavity, and then the cavity is welded by gas shield welding to seal the steel pipe inside the cavity, and then build-up welding is continued until the groove is filled, and finally surface welding is performed to obtain the clad material assembly. In the rolling process, the clad material assembly coming out of the heating furnace is rolled to produce a large clad steel sheet. The first n passes of the entire rolling process are widthwise rolling, and from the (n+1)th pass onward, longitudinal rolling is employed. The reduction amount of the first pass is 25 mm or more, and the rolling temperature is 1060°C or higher. The width of the material after the nth pass is Wt + (0~40) mm, where Wt is the target width of the large clad steel sheet. The rolling temperature of the nth pass is 1030°C or higher. Between the nth pass and the (n+1)th pass, and between the (n+2)th pass and the (n+3)th pass, the material is water-cooled once in a reciprocating motion using six sets of headers, with a cooling water volume of 120~180 m³ in the upper header of each set of headers. 3 / h, the cooling water volume in the lower header is 160-220m 3 The rolling speed is 0.8 to 1.2 m / s, the reduction amount from the (n+1)th pass to the (n+3)th pass is 40 mm or more, the rolling temperature of the (n+1)th pass is 950°C or higher, in the mth pass the rolling temperature is 900°C or higher and the material is rolled until the material thickness is 2.5 to 3.5 times the target thickness of the clad steel sheet, then water cooling is performed and the material is cooled until the surface temperature is 840°C or lower, then the second stage of rolling is performed and the material thickness is rolled until the material thickness is the target thickness of the clad steel sheet to complete the entire rolling process, the rolling temperature of the first pass of the second stage of rolling is 810°C to 840°C and the rolling temperature of the final pass is 780 to 810°C.

[0010] The chemical composition of the base layer of the aforementioned clad steel sheet is, by mass percentage, C: 0.03~0.16%, Si: 0.11~0.29%, Mn: 1.31~1.54%, P: 0.018% or less, S: 0.0030% or less, Cr: 0.06~0.29%, Ni: 0.24% or less, Cu: 0.24% or less, Mo: 0.24% or less, Nb: 0.011~0.034%, Ti: 0.011~0.019%, Al: 0.030~0.040%, with the remainder being Fe and unavoidable impurities. The chemical composition of the clad layer of the aforementioned clad steel sheet is, by mass percentage, C: 0.15% or less, Si: 1.00% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.030% or less, Ni: 6.0-22.0%, Cr: 16.0-26.0%, Mo: 3.0% or less, with the remainder being Fe and unavoidable impurities. The bonding ratio of the joint interface of the clad steel plate is 100%, and the shear strength is 300 MPa or more.

[0011] Thus, one embodiment of the present invention, compared to the conventional technology, ensures the surface quality of the stainless steel clad material by encasing it in the base material and seal material through the assembly method, seal welding, and sealing method, and also eliminates the need for grooved material manufacturing as in the conventional technology, resulting in a higher yield. Furthermore, it prevents air leakage and cracking of the clad material assembly while achieving vacuum evacuation, thereby ensuring interfacial bonding quality. On the other hand, by combining the assembly, seal welding, and sealing method with rolling technology, and particularly by employing a completely new rolling technology in this field, it ensures temperature uniformity of the clad material assembly and guarantees effective penetration into the center of the clad material assembly. This not only allows the advantages of both the base material and the clad material to be realized, but more importantly, it ensures interfacial bonding quality between the base material and the clad material. [Brief explanation of the drawing]

[0012] For clear representation and explanation, in each drawing of the present invention, the dimensions of some structures or parts are enlarged relative to other structures or parts, and are therefore used solely to illustrate the basic structure of the subject matter of the present invention. [Figure 1] Figure 1 is a flowchart of the manufacturing method provided by the present invention. [Figure 2] Figure 2 is a schematic diagram of the materials during the manufacturing stage of the clad material assembly in the first embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view of a material assembly obtained by a seal welding process during the manufacturing stage of a clad material assembly in the first embodiment of the present invention, wherein the cross-section passes through the central axis of the steel pipe and is perpendicular to the width direction of the material assembly. [Figure 4] Figure 4 is an enlarged view of the circular framed area in Figure 3. [Figure 5]FIG. 5 is another cross-sectional schematic view of the material assembly obtained by the seal welding process in the clad material assembly manufacturing stage of the first embodiment of the present invention, and the cross-section passes through the central axis of the steel pipe and is perpendicular to the thickness direction of the material assembly. [Figure 6] FIG. 6 is a schematic view of a single-sided stainless clad steel plate product obtained according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a schematic view of the material in the clad material assembly manufacturing stage of the second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional schematic view of the material assembly obtained by the seal welding process in the clad material assembly manufacturing stage of the second embodiment of the present invention, and the cross-section passes through the central axis of the steel pipe and is perpendicular to the width direction of the material assembly. [Figure 9] FIG. 9 is an enlarged view of the circular frame area of FIG. 8. [Figure 10] FIG. 10 is another cross-sectional schematic view of the material assembly obtained by the seal welding process in the clad material assembly manufacturing stage of the second embodiment of the present invention, and the cross-section passes through the central axis of the steel pipe and is perpendicular to the thickness direction of the material assembly. [Figure 11] FIG. 11 is a schematic view of a single-sided stainless clad steel plate product obtained according to the second embodiment of the present invention. [Figure 12] FIG. 12 is a schematic view of the material in the clad material assembly manufacturing stage of the third embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional schematic view of the material assembly obtained by the seal welding process in the clad material assembly manufacturing stage of the third embodiment of the present invention, and the cross-section passes through the central axis of the steel pipe and is perpendicular to the width direction of the material assembly. [Figure 14] FIG. 14 is an enlarged view of the circular frame area of FIG. 13. [Figure 15] FIG. 15 is another cross-sectional schematic view of the material assembly obtained by the seal welding process in the clad material assembly manufacturing stage of the third embodiment of the present invention, and the cross-section passes through the central axis of the steel pipe and is perpendicular to the thickness direction of the material assembly. [Figure 16]Figure 16 is a schematic diagram of a single-sided stainless steel clad steel sheet product obtained according to the third embodiment of the present invention. [Figure 17] Figure 17 is a schematic diagram of the materials during the manufacturing stage of the clad material assembly in the fourth embodiment of the present invention. [Figure 18] Figure 18 is a schematic cross-sectional view of a material assembly obtained by a seal welding process during the manufacturing stage of a clad material assembly in the fourth embodiment of the present invention, wherein the cross-section passes through the central axis of the steel pipe and is perpendicular to the width direction of the material assembly. [Figure 19] Figure 19 is an enlarged view of the circular framed area in Figure 18. [Figure 20] Figure 20 is another schematic cross-sectional view of a material assembly obtained by a seal welding process during the manufacturing stage of a clad material assembly in the fourth embodiment of the present invention, wherein the cross-section passes through the central axis of the steel pipe and is perpendicular to the thickness direction of the material assembly. [Figure 21] Figure 21 is a schematic diagram of a single-sided stainless steel clad steel sheet product obtained according to the fourth embodiment of the present invention. [Figure 22] Figure 22 is a schematic diagram of the materials during the manufacturing stage of the clad material assembly in the fifth embodiment of the present invention. [Figure 23] Figure 23 is a schematic cross-sectional view of a material assembly obtained by a seal welding process during the manufacturing stage of a clad material assembly in the fifth embodiment of the present invention, wherein the cross-section passes through the central axis of the steel pipe and is perpendicular to the width direction of the material assembly. [Figure 24] Figure 24 is an enlarged view of the circular framed area in Figure 23. [Figure 25] Figure 25 is another schematic cross-sectional view of a material assembly obtained by a seal welding process during the manufacturing stage of a clad material assembly in the fifth embodiment of the present invention, wherein the cross-section passes through the central axis of the steel pipe and is perpendicular to the thickness direction of the material assembly. [Figure 26] Figure 26 is a schematic diagram of a single-sided stainless steel clad steel sheet product obtained according to the fifth embodiment of the present invention. [Modes for carrying out the invention]

[0013] One embodiment of the present invention provides a method for manufacturing a single-sided stainless steel clad plate for bridge structures, and a single-sided stainless steel clad plate for bridge structures manufactured by the manufacturing method of one embodiment of the present invention.

[0014] Specifically, as shown in Figure 1, the manufacturing method includes the following steps: material preparation, separation agent application, assembly, seal welding, vacuuming, sealing, heating, rolling, cooling, cutting, and planarization. That is, the present invention manufactures a single-sided stainless steel clad plate by the steps of material preparation - separation agent application - assembly - seal welding - vacuuming - sealing - heating - rolling - cooling - cutting - planarization.

[0015] Of these, the clad material is manufactured through a material preparation process, a separation agent application process, an assembly process, a seal welding process, a vacuum drawing process, and a sealing process. Therefore, the steps from the material preparation process to the sealing process are referred to in this application as the clad material manufacturing stage. Subsequently, a large clad plate is manufactured from the clad material through a heating process, a rolling process, and a cooling process. Therefore, the steps from the heating process to the cooling process are referred to in this application as the clad material rolling stage. Finally, at least two small single-sided stainless steel clad plates, i.e., single-sided stainless steel clad plate products, are manufactured from the large clad plate through a cutting process and a flattening process. Therefore, this stage is referred to in this application as the plate product stage.

[0016] Furthermore, the present invention provides several embodiments of the clad material manufacturing step, each of which is described in detail below.

[0017] <First embodiment of the clad material manufacturing stage> Figures 2 to 6 show a first embodiment of the clad material manufacturing stage.

[0018] In this embodiment, referring to Figure 2, the material preparation step specifically includes the following: Two carbon steel materials with thickness T1, length L1, and width W1 are prepared and used as two base materials, and are distinguished as base material 11A and base material 11B in Figure 2. Polish the clad planned surfaces of each base material. For example, polish the surface 11As of the base material 11A and the surface 11Bs of the base material 11B to remove the surface oxide scale and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm. Prepare two stainless steel materials with a thickness T2, a length L2, and a width W2, and use them as two clad materials, which are distinguished as the composite materials 12A and 12B in FIG. 2. Polish the clad planned surfaces of each clad material. For example, polish the surface A1s of the clad material 12A and the surface B1s of the clad material 12B to remove the surface oxide scale and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm.

[0019] Among them, L2 < L1 and W2 < W1, and the dimensions of the length and width of the clad material are smaller than those of the length and width of the base material. More preferably, L1 ≥ 2500 mm, W2 ≥ 1600 mm, T1 ≥ 60 mm, L1 - L2 is in the range of 90 to 150 mm, and W1 - W2 is also in the range of 90 to 150 mm.

[0020] In this embodiment, each base material is a uniform thickness material with a thickness T1, and accordingly, the base material layer (the layer obtained by the base material by the manufacturing method) of the stainless steel clad plate obtained by this embodiment has a uniform thickness.

[0021] Here, the "clad planned surface" refers to the surface where the base material and the clad material need to be interfacially joined when forming the clad plate. For example, in a pair of base materials and clad materials, either one of the two surfaces in the thickness direction is selected as the clad planned surface, and interfacial joining is performed with each other in the subsequent process. For example, the surface 11As of the base material 11A and the surface A1s of the clad material 12A are interfacially joined with each other in the subsequent process, and the surface 11Bs of the base material 11B and the surface B1s of the clad material 12B are interfacially joined with each other in the subsequent process.

[0022] Preferably, the surface 11As of the base material 11A and the surface 11Bs of the base material 11B are polished using a grinding machine, belt sander, or milling machine, respectively, to remove the oxide scale on the surface and expose the metallic luster. The surface A1s of the clad material 12A and the surface B1s of the clad material 12B are polished using a wire brush, respectively, to remove the oxide scale on the surface and expose the metallic luster.

[0023] While this description only covers surface polishing of the intended cladding surfaces of each base material and cladding material, surface polishing can also be performed on other surfaces of each base material and cladding material. Such additional surface polishing is not essential to achieving the technical effects of the present invention, but it may be preferable.

[0024] Furthermore, in this embodiment, the separation agent application step specifically includes applying the separation agent to the unclad surface of at least one clad material. Specifically, the separation agent can be applied to the unclad surface of each clad material, and the unclad surface can be, for example, surface A2s of clad material 12A, surface B2s of clad material 12B, or one of the two clad materials can be selected and the separation agent applied to it. This prevents the two clad materials from joining together in the subsequent clad material rolling process, which would make cutting difficult.

[0025] To make it clear, the non-clad surface is on the opposite side of the clad surface of the clad material, and these two surfaces constitute two surfaces in the thickness direction of the clad material.

[0026] Regarding the components of the separating agent, the first option is a coating liquid containing silicon dioxide and magnesium oxide, with a mass ratio of silicon dioxide to magnesium oxide of 3:1. The separating agent of this embodiment can achieve a good separation effect and ensure the separation of the two subsequent clad plates. When using the separating agent, the total amount of separating agent 13 (see Figure 3) between the two clad materials is 20 y·mg / m 2Herein, y is the ratio of the thickness of the clad material produced in the clad material manufacturing process to the thickness of the clad plate produced by subsequent rolling, and this ratio is also called the clad material rolling compression ratio. Now, a method for preparing the separating agent is provided. Polyvinyl alcohol and thermosetting phenolic resin are mixed in a mass ratio of 1:1 to obtain adhesive powder. Silicon dioxide and magnesium oxide are mixed in a mass ratio of 3:1 to obtain separating agent powder. The separating agent powder, adhesive powder and water are mixed in a mass ratio of 27:3:70 to obtain a fluid separating agent coating liquid. After the application of the separating agent is completed, and before the subsequent assembly process, the clad material coated with the separating agent is heated and dried in a trolley furnace at a drying temperature of 340-360°C and a drying time of 35-45 min.

[0027] As a second option for the components of the aforementioned separating agent, the composition is 25-35% silicon nitride + 5-10% thermosetting amino resin + 55-70% water by weight. Compared to conventional separating agents, and even compared to the first embodiment of the separating agent described above, the separating agent of this embodiment not only achieves a good separation effect and can guarantee the separation of two subsequent cladding plates, but also, the active ingredient silicon nitride has high chemical stability, excellent high temperature resistance and thermal shock resistance, and the thermosetting amino resin used as an adhesive can cure at low temperatures, is non-toxic, and can achieve a strong adhesive effect in small amounts, so overall it is inexpensive, easy to operate, and has good separation and adhesion effects.

[0028] Herein, a preferred method for preparing the second option of the separating agent is provided, which includes the following: First, 5-10% silicon nitride (weight percent) is placed in a container such as a beaker, then 15-25% water is added and stirred. Once the silicon nitride is free of particles and there are no more bubbles, 2-3% thermosetting amino resin is added and stirring continues. When it becomes viscous, the remaining silicon nitride and water are added and stirred for 3-5 minutes, then the remaining thermosetting amino resin is added. Stirring continues until it becomes viscous to obtain the separating agent.

[0029] Regarding the second option of the separating agent, the total amount of separating agent 13 (see Figure 3) between the two clad materials is applied to a thickness of 0.2 to 0.5 mm. After the application of the separating agent is complete, and before the subsequent assembly process, the clad materials coated with the separating agent are heated and dried at a drying temperature of 100 to 250°C and a drying time of 20 to 40 minutes. It is important to note that in the drawings of this application, the thickness dimension of the separating agent 13 between the two clad materials is shown enlarged for ease of understanding and explanation; that is, the thickness of the separating agent 13 shown in the drawings is an enlarged ratio to the base material thickness, clad material thickness, and the sealing material width described later.

[0030] Regarding the first and second options for the separating agent, when the separating agent is applied to both surface A2s of clad material 12A and surface B2s of clad material 12B, half of the total amount is applied to surface A2s and surface B2s respectively. When the separating agent is applied to only one of either surface A2s or surface B2s, the total amount is applied.

[0031] Furthermore, referring to Figure 3, the assembly process specifically involves using clad material 12A and clad material 12B as intermediate layers, stacking base material 11A on top and base material 11B on the bottom, arranging four sealing materials 14 to surround the four sides of the intermediate layer, and then gas-shielded welding between the upper end of the sealing material 14 and base material 11A, and between the lower end of the sealing material 14 and base material 11B to form the material assembly.

[0032] Specifically, in selectable embodiments, the base material 11A, clad material 12A and clad material 12B, and base material 11B are first laminated, then the seal material 14 is attached to the four sides of the clad material 12A and clad material 12B, and finally the upper end of the seal material 14 and the surface 11As of the base material 11A, and the lower end of the seal material 14 and the surface 11Bs of the base material 11B can be gas-shielded welded. Of course, in modified embodiments, the lower end of the seal material 14 and the surface 11Bs of the base material 11B can be gas-shielded welded first, the seal material 14 forming a rectangular frame on the surface 11Bs of the base material 11B, then the clad material 12B and clad material 12A are sequentially placed within the frame, the clad material 12A and the frame are further covered with the base material 11A, and finally the upper end of the seal material 14 and the surface 11As of the base material 11A can be gas-shielded welded. Furthermore, in a further modified embodiment, the upper end of the sealing material 14 and the surface 11As of the base material 11A can be gas-shielded, then the base material 11B, clad material 12B, and clad material 12A can be sequentially laminated from bottom to top, the integrated sealing material 14 and base material 11A can be placed over and around the clad material 12A and clad material 12B, and finally the lower end of the sealing material 14 and the surface 11Bs of the base material 11B can be gas-shielded. None of these embodiments depart from the spirit of the present invention.

[0033] More preferably, in the assembly process, the base material 11A, clad material 12A and clad material 12B, and base material 11B are stacked, and with the upper or lower end of the sealing material 14 not welded to the base material, the entire stacked steel material is placed under a four-column hydraulic press, and a pressure of 500 tons or more is applied to the opposite surfaces of the two base materials (i.e., the upper surface of base material 11A and the lower surface of base material 11B). This makes the contact between adjacent steel materials closer.

[0034] Preferably, during the assembly process, when gas shield welding is performed between the end of the seal material 14 and the base material, the welding current is controlled to 220-240A, the welding voltage to 28-32V, the welding speed to 300-360mm / min, and the interpass temperature to 140-160°C. In addition, before gas shield welding, the base materials 11A and 11B are preferably preheated and baked with a torch, with a baking temperature of 150-250°C.

[0035] In this embodiment, referring to Figure 3, in the intermediate layer, the clad material 12A and the clad material 12B are stacked vertically, and the sealing material 14 surrounds the four sides of the clad material 21 and the clad material 22.

[0036] To make it easier to understand, in the material assembly obtained in the assembly process, the surface 11As of the base material 11A and the surface A1s of the clad material 12A are in contact with each other as clad surfaces, the surface 11Bs of the base material 11B and the surface B1s of the clad material 12B are in contact with each other as clad surfaces, and the surface A2s of the clad material 12A and the surface B2s of the clad material 12B are in contact with each other as non-clad surfaces.

[0037] Furthermore, grooves are formed on all four sides of the resulting material assembly, surrounded by the base material 11A, the sealing material 14, and the base material 11B. Preferably, the depth of the grooves on all four sides of the material assembly is set to be the same, and as shown in Figure 4, the depth D is in the range of 40 to 60 mm. By controlling this depth D, it is possible to effectively prevent cracks in the welded area during the rolling of the clad material, and also to prevent the formation of thermal cracks during subsequent seal welding due to deeper penetration, which would affect the seal welding quality of the clad material.

[0038] To make it understandable, the groove depth depends on the difference in length and width between the clad material and the base material, as well as the thickness of the sealant 14. For example, in the assembly process, the clad material is centered relative to the base material, and the distance from two lateral (i.e., width) sides (i.e., long sides) of the clad material to the corresponding two sides (i.e., long sides) of the base material is equal, and this distance is 45-75 mm. The distance from two longitudinal (i.e., length) sides (i.e., short sides) of the clad material to the corresponding two sides (i.e., short sides) of the base material is also equal, and this distance is 45-75 mm. The thickness T3 of the sealant is 10-15 mm, and the groove depth D on the long sides of the material assembly is (W1-W2-2T3) / 2, and the groove depth D on the short sides is (L1-L2-2T3) / 2.

[0039] Furthermore, regarding the overall dimensions of the four sealing materials 14, on the long side of the material assembly, the length of the sealing material 14 is L31 = L2 to L2 - 2 mm, and on the short side, the length of the sealing material 14 is L32 = W2 to W2 - 2 mm. The width W3 of the sealing material 14 is 2T2 to 2T2 - 2 mm, and the thickness T3 is 10 to 15 mm as described above. Preferably, the width W3 of the sealing material 14 on all four sides of the material assembly is the same, and the thickness T3 is also the same. Of course, it is not limited to this. What needs to be explained here is that, as mentioned above, in order to facilitate understanding and explanation, the thickness dimension of the separating agent 13 is shown enlarged in Figure 3, and accordingly, the width of the sealing material 14 shown in Figures 3 and 4 is shown to be larger than the sum of the thicknesses of the two cladding materials, but this is simply because the thickness dimension of the separating agent 13 is enlarged, and in reality, the width W3 of the sealing material 14 is equal to the sum of the thicknesses of the cladding material 12A and cladding material 12B, or is about 2 mm smaller.

[0040] More preferably, referring to Figure 4, grooves are provided at both the upper and lower ends of the outer surface of the seal material 14, with a groove angle of 10 to 20° and a groove vertical depth P of 10 to 15 mm. Here, "outer surface of the seal material 14" refers to the surface of the seal material 14 that is separated from the cladding material 12A and cladding material 12B. In other words, grooves are provided at both the upper and lower ends of one surface of the seal material 14, and in the assembly process, the seal material 14 is assembled with the base material 11A, base material 11B, cladding material 12B, and cladding material 12A so that the "one surface" of the seal material 14 with the groove faces outwards. By providing grooves, spot welding processes on the inside of the seal material are avoided, thermal effects on the base material due to multiple welding are avoided, and the subsequent seal welding groove is facilitated, ensuring rigidity.

[0041] Referring to Figure 4, the groove angle K1 at the upper end and the groove angle K2 at the lower end of the outer surface of the sealing material 14 are both 10 to 20°, and they may be the same or different.

[0042] Furthermore, a circular through-hole is provided in the sealing material on one side of the material assembly, and in this assembly process, a steel pipe 16 with an outer diameter r is welded to the through-hole. The through-hole may be processed before the gas shield welding of the sealing material 14 and the base materials 11A and 11B, or it may be processed after the gas shield welding is completed and the material assembly is formed. None of these methods deviate from the technical intent of this application.

[0043] Preferably, the diameter of the through hole matches the outer diameter of the steel pipe 16, and both are r.

[0044] More preferably, as shown in Figure 5, the through-hole is provided in the sealant 14 on one of the short sides of the material assembly, and the through-hole is centered at a position that is 1 / 3 of the length (i.e., 1 / 3 of L32) and 1 / 2 of the width (i.e., 1 / 2 of W3) of the sealant 14. Referring to Figure 4, the end face of the steel pipe 16 is flush with the inner surface of the sealant 14. This ensures the effect of vacuuming.

[0045] Preferably, the length range of the steel pipe 16 is T3+2D to T3+2D+R.

[0046] Furthermore, in this embodiment, the seal welding process specifically includes the following: Overlay welding is performed on the grooves on the four sides of the material assembly, specifically using, for example, submerged arc overlay welding. In the overlay welding process, as shown in Figures 4 and 5, a cavity 15H with radius R>r is left around the steel pipe 16, concentric with the steel pipe 16. When the build-up welding of the groove on the side where the steel pipe 16 is located reaches a penetration depth of 2 / 3 of the groove depth, and the build-up welding of the grooves on the other sides reaches a penetration depth of 2 / 3 or more of the groove depth, for example in an embodiment where the groove depths of all four sides are D, that is, when the build-up welding of the groove on the side where the steel pipe 16 is located reaches a penetration depth of 2 / 3D, and the build-up welding of the grooves on the other sides reaches a penetration depth of 2 / 3D or more, the build-up welding is stopped.

[0047] As you will soon understand, a four-sided frame-shaped filling layer is formed on the outside of the frame formed by the sealing material 14 by build-up welding. Referring to Figures 3 to 5, the filling layer formed by build-up welding is labeled 15.

[0048] More preferably, the seal welding process is terminated when the build-up welding of the groove on the side where the steel pipe 16 is located reaches a penetration depth of 2 / 3 of the groove depth, and the build-up welding of the grooves on the other sides reaches a penetration depth equal to the groove depth. For example, in an embodiment where the groove depths on all four sides are D, that is, when the build-up welding of the groove on the side where the steel pipe 16 is located reaches a penetration depth of 2 / 3D, and the build-up welding of the grooves on the other sides reaches a groove depth of D. This completes the filling of the grooves on the other three sides by build-up welding, ensuring the airtightness of the material assembly during vacuuming, and also facilitates the complete seal welding of subsequent vacuum tubes into the grooves, thereby once again guaranteeing the airtightness of the clad material.

[0049] Furthermore, in the build-up welding process, a multi-layer multi-pass welding method is employed, where the upper and lower ends are welded first, followed by the intermediate region. This not only sufficiently dissipates the heat generated during the welding process but also prevents the sealant from melting through. Each layer is welded in at least four passes, with an interpass temperature of 140-160°C, a total of 6-8 welded layers, and an interlayer temperature of 150-250°C. This effectively improves the strength of the welded joint and reduces the impact of welding on the microstructure properties of the base material and cladding material.

[0050] Furthermore, before build-up welding, the flux to be used should be preheated and kept warm. The heating temperature should be 300-350°C, the heating time 90-120 minutes, and the warming temperature 100-150°C.

[0051] Preferably, during the build-up welding process, the welding current is 550-650A, the welding voltage is 28-32V, and the welding speed is 400-500mm / min.

[0052] Furthermore, after stopping the build-up welding as described above, evacuate the material assembly and then seal it. The evacuation process can be implemented by adopting known techniques. However, this embodiment provides a preferred solution. Specifically, in this preferred evacuation process, evacuate the internal space of the material assembly three times and break the vacuum twice through the steel pipe, and finally maintain the vacuum degree of the internal space of the material assembly at 10 -2 Pa or less.

[0053] More preferably, the evacuation process includes the following. First, connect the steel pipe to a vacuum pump and evacuate the internal space of the material assembly to a vacuum degree of 10 -2 Pa or less and then hold it for 4 hours or more. Next, connect the steel pipe to a nitrogen supply device to break the vacuum of the material assembly and fill it with nitrogen gas. After that, connect the steel pipe to the vacuum pump again and evacuate the material assembly to a vacuum degree of 10 -1 Pa or less without holding. Next, connect the steel pipe to the nitrogen supply device again to break the vacuum of the material assembly and fill it with nitrogen gas. Finally, as the third time, connect the steel pipe to the vacuum pump and evacuate the material assembly to a vacuum degree of 10 -2 Pa or less, and then directly perform the sealing process without holding.

[0054] Furthermore, specifically, in the sealing process, heat the steel pipe 16 with a torch, press it flat, and then fold it into the previously left cavity 15H. Next, completely weld the cavity by gas shielded welding and seal-weld the steel pipe in the cavity 15H. Then, continue with the build-up welding until the groove on the side where the steel pipe 16 is located is filled, and finally perform surface welding to obtain the clad material.

[0055] Thus, the assembly, seal welding, and sealing process of the present invention leaves a cavity 15H in the weld area, increasing the processing space of the steel pipe 16, reducing the difficulty of seal welding, improving seal welding efficiency, preventing airtight leakage during sealing, preventing the steel pipe 16 from falling off due to impact, thereby ensuring the overall airtightness of the clad material, and preventing the occurrence of cracks and airtight leakage during rolling. Furthermore, the interfacial bonding of the manufactured clad plate is excellent and production costs are reduced.

[0056] To understand this, the shape, dimensions, and assembly method of the materials prepared during the clad material manufacturing stage affect the structural shape of the final stainless steel clad sheet.

[0057] As shown in Figure 6, in this embodiment, based on the arrangement of a base material of uniform thickness prepared in the material preparation step and clad material 12A and clad material 12B as intermediate layers in the assembly step, the clad material of this embodiment, after going through the subsequent clad material rolling step and sheet product step, produces two stainless steel clad sheets in which the thickness of the base material layer is uniform, and the length and width dimensions of the clad material layer and the base material layer are the same.

[0058] For example, the obtained stainless steel clad plate 10A has a base material layer 11A and a clad material layer 12A that were obtained by rolling from the aforementioned base material 11A and clad material 12A, respectively. Therefore, the original reference numerals for the base material 11A and clad material 12A are used, the base material layer 11A is a carbon steel material of uniform thickness, and the clad material layer 12A is a stainless steel material. The length and width dimensions of the clad material layer 12A and the base material layer 11A are the same.

[0059] For example, the obtained stainless steel clad plate 10B is obtained by rolling its base material layer 11B and clad material layer 12B, respectively, so the original reference numerals for base material 11B and clad material 12B are continued to be used. The base material layer 11B is a carbon steel material of uniform thickness, and the clad material layer 12B is a stainless steel material, and the length and width dimensions of the clad material layer 12B and the base material layer 11B are the same.

[0060] In general, a single-sided stainless steel clad sheet is provided, and the clad material manufactured according to this embodiment is produced through a clad material rolling stage and a sheet product stage. The clad sheet is a fully covered, uniform thickness sheet with a total thickness of 5 to 55 mm, a base material layer thickness of 4 to 45 mm, and a clad material layer thickness of 1 to 10 mm.

[0061] The steps in the manufacturing process of the clad material according to this embodiment have been described in detail above. In the several test examples described later, Test Examples 1 to 3 employ this embodiment to manufacture the clad material, and stainless steel clad plates were manufactured using the manufactured clad material. Here, Table 1 shows some of the parameters of the clad material in these examples, and please refer to the above explanation for the parameters indicated by the symbols.

[0062] [Table 1]

[0063] <Second embodiment of the clad material manufacturing stage> Referring to Figures 7 to 11, a second embodiment of the clad material manufacturing stage is shown. The only difference between this embodiment and the first embodiment of the clad material manufacturing stage described above is the shape of the base material prepared in the material preparation step. On the other hand, the separation agent application step, assembly step, seal welding step, vacuuming step, sealing step, etc., are the same as in the first embodiment. Below, only the material preparation step with differences will be described in detail, and other details will be understood by referring to the drawings and the first embodiment of the clad material manufacturing stage described above, so redundant explanations will be omitted.

[0064] Referring to Figure 7, in this embodiment, the material preparation step specifically includes the following: Two carbon steel materials with length L1, width W1, and thickness varying along the X direction are prepared and used as two base materials, which are distinguished as base material 21A and base material 21B in Figure 7. Polish the clad planned surfaces of each base material, for example, polish the surface 21As of the base material 21A and the surface 21Bs of the base material 21B, remove the surface oxide scale to expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm. Prepare two stainless steel materials with a thickness T2, a length L2, and a width W2, and use them as two clad materials, which are distinguished as clad materials 22A and 22B in FIG. 7. Polish the clad planned surfaces of each clad material, for example, polish the surface A1s of the clad material 22A and the surface B1s of the clad material 22B, remove the surface oxide scale to expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm.

[0065] Among them, L2 < L1 and W2 < W1, and the length and width dimensions of the clad material are smaller than the length and width dimensions of the base material. More preferably, L1 ≧ 2500 mm, W2 ≧ 1600 mm, L1 - L2 is in the range of 90 to 150 mm, and W1 - W2 is also in the range of 90 to 150 mm.

[0066] In addition, the base materials 21A and 21B are carbon steel materials whose thickness changes along the X direction, that is, the thickness is not uniform and the thickness changes along the X direction. Here, the X direction is the width direction or the length direction of the base material, and in the embodiment shown in FIG. 10, the X direction is shown as the length direction of the base material.

[0067] More preferably, the cladding surface 21As of the base material 21A and the cladding surface 21Bs of the base material 21B are complementary to each other; that is, when these two surfaces face each other, they are complementary, and this complementarity causes the non-cladding surface of the base material 21A (i.e., the upper surface of the base material 21A in Figure 7) and the non-cladding surface of the base material 21B (i.e., the lower surface of the base material 21B in Figure 7) to be parallel. Accordingly, as shown in Figure 8, in the material assembly manufactured in the subsequent assembly process, the upper surface of the base material 21A and the lower surface of the base material 21B are parallel. From another perspective, the cladding surface 21As of the base material 21A and the cladding surface 21Bs of the base material 21B are complementary to each other if, when the cladding surface 21As of the base material 21A and the cladding surface 21Bs of the base material 31B are fitted together facing each other vertically, they can be in close contact surface to surface; that is, when the cladding surface 21As of the base material 21A and the cladding surface 21Bs of the base material 21B are fitted together facing each other vertically, the sum of the thicknesses of the base material 21A and the base material 21B is constant.

[0068] In the embodiment shown in the drawings, both base material 21A and base material 21B are non-uniform thickness plates whose thickness changes monotonically along the X direction, and both the planned cladding surface 21As of base material 21A and the planned cladding surface 21Bs of base material 21B are inclined planes. Of these, the inclination angle of the planned cladding surface 21As (for example, the angle with respect to the non-cladding surface of base material 21A) is equal to the inclination angle of the planned cladding surface 21Bs (for example, the angle with respect to the non-cladding surface of base material 21B).

[0069] To understand this, the shape, dimensions, and assembly method of the materials prepared during the clad material manufacturing stage affect the structural shape of the final stainless steel clad sheet.

[0070] In this embodiment, as shown in Figure 11, based on the arrangement of a base material prepared in the material preparation step with a monotonically varying thickness along the X direction, and clad material 22A and clad material 22B as intermediate layers in the assembly step, the clad material of this embodiment, after going through the subsequent clad material rolling step and sheet product step, produces two stainless steel clad sheets in which the base material layer has a monotonically varying thickness along the X direction, and the four sides of the clad material layer and the base material layer are flush.

[0071] For example, as shown in Figure 11, the obtained stainless steel clad sheet 20A has a lower carbon steel base layer 21A and an upper stainless steel clad layer 22A, which are obtained by rolling from the aforementioned base material 21A and clad material 22A, respectively, so the original reference numerals for base material 21A and clad material 22A are continued to be used. Of these, the thickness of the base material layer 21A changes along the X direction, specifically, the thickness changes monotonically along the X direction, and more specifically, the upper surface of the base material layer 21A is an inclined plane with respect to the lower surface of the base material layer 21A. The four sides of the clad material layer 22A and the base material layer 21A are flush, and the clad material layer 22A just completely covers the upper surface of the base material layer 21A.

[0072] Furthermore, as shown in Figure 11, the obtained stainless steel clad plate 20B is obtained by rolling its lower carbon steel base layer 21B and upper stainless steel clad layer 22B from the aforementioned base material 21B and clad material 22B, respectively, so the original reference numerals for base material 21B and clad material 22B are continued to be used. Of these, the thickness of the base material layer 21B changes along the X direction, specifically, the thickness changes monotonically along the X direction, and more specifically, the upper surface of the base material layer 21B is an inclined plane with respect to the lower surface of the base material layer 21B. The four sides of the clad material layer 22B and the base material layer 21B are flush, and the clad material layer 22B completely covers the upper surface of the base material layer 21B.

[0073] In general, a single-sided stainless steel clad sheet is provided, and the clad material manufactured according to this embodiment is produced through a clad material rolling stage and a sheet product stage. The clad sheet has a total thickness of (5~47)~(7~55) mm, a base material layer thickness of (4~37)~(6~45) mm, a clad material layer thickness of 1~10 mm, and is a non-uniform thickness sheet with a monotonically changing thickness along the X direction.

[0074] The steps in the manufacturing process of the clad material according to this embodiment have been described in detail above. In the several test examples described later, test examples 4 to 6 employ this embodiment to manufacture the clad material, and stainless steel clad plates were manufactured using the manufactured clad material. Here, Table 2 shows some of the parameters of the clad material in these examples, and please refer to the above explanation for the parameters indicated by the symbols.

[0075] [Table 2]

[0076] <Third embodiment of the clad material manufacturing stage> Referring to Figures 12 to 16, a third embodiment of the clad material manufacturing stage is shown. The only difference between this embodiment and the first embodiment of the clad material manufacturing stage described above is the shape of the base material prepared in the material preparation step. On the other hand, the separation agent application step, assembly step, seal welding step, vacuuming step, sealing step, etc., are the same as in the first embodiment. Below, only the material preparation step with differences will be described in detail, and other details will be omitted as they can be understood by referring to the drawings and the first embodiment of the clad material manufacturing stage described above.

[0077] In this embodiment, referring to Figure 12, the material preparation step specifically includes the following: Two carbon steel materials with length L1, width W1, and thickness varying along the X direction are prepared and used as two base materials, which are distinguished as base material 31A and base material 31B in Figure 12. Polish the clad planned surfaces of each base material. For example, polish the surface 31As of the base material 31A and the surface 31Bs of the base material 31B to remove the surface oxide scale and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm. Prepare two stainless steel materials with a thickness T2, a length L2, and a width W2, and use them as two clad materials, which are distinguished as clad materials 32A and 32B in FIG. 7. Polish the clad planned surfaces of each clad material. For example, polish the surface A1s of the clad material 32A and the surface B1s of the clad material 32B to remove the surface oxide scale and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad planned surface is less than 5 μm.

[0078] Among them, L2 < L1 and W2 < W1, and the dimensions of the length and width of the clad material are smaller than those of the base material. More preferably, L1 ≧ 2500 mm, W2 ≧ 1600 mm, L1 - L2 is in the range of 90 - 150 mm, and W1 - W2 is also in the range of 90 - 150 mm.

[0079] Also, the base materials 31A and 31B are carbon steel materials whose thickness changes along the X direction, that is, the thickness is not uniform and changes along the X direction. Here, the X direction is the width direction or the length direction of the base material, and in the embodiment shown in FIG. 15, the X direction is shown as the length direction of the base material.

[0080] More preferably, the cladding surface 31As of the base material 31A and the cladding surface 31Bs of the base material 31B are complementary to each other; that is, when these two surfaces face each other, they are complementary, and this complementarity causes the non-cladding surface of the base material 31A (i.e., the upper surface of the base material 31A in Figure 13) and the non-cladding surface of the base material 31B (i.e., the lower surface of the base material 31B in Figure 13) to be parallel. Accordingly, as shown in Figure 13, in the material assembly manufactured in the subsequent assembly process, the upper surface of the base material 31A and the lower surface of the base material 31B are parallel. From another perspective, the cladding surface 31As of the base material 31A and the cladding surface 31Bs of the base material 31B are complementary to each other if, when the cladding surface 31As of the base material 31A and the cladding surface 31Bs of the base material 31B are fitted together facing each other vertically, they can be in close contact surface to surface; that is, when the cladding surface 31As of the base material 31A and the cladding surface 31Bs of the base material 31B are fitted together facing each other vertically, the sum of the thicknesses of the base material 31A and the base material 31B is constant.

[0081] In the embodiment shown in the drawings, both base material 31A and base material 31B are non-uniform thickness plates whose thickness changes non-monotonically along the X direction, and both the planned cladding surface 31As of base material 31A and the planned cladding surface 31Bs of base material 31B include two or more planes arranged along the X direction.

[0082] For example, both the planned cladding surface 31As of the base material 31A and the planned cladding surface 31Bs of the base material 31B, as shown in Figure 12, have seven planes. Taking the planned cladding surface 31Bs of the base material 31B as an example, in Figure 12, from left to right, there is one horizontal plane, one upward-sloping plane, one downward-sloping plane, one horizontal plane, one downward-sloping plane, one upward-sloping plane, and one horizontal plane. Of course, the specific shapes of the planned cladding surface 31As of the base material 31A and the planned cladding surface 31Bs of the base material 31B shown in the figure are merely examples, and the number of inclined planes included in each is not limited to those shown.

[0083] Furthermore, in this embodiment, the shape of each clad material prepared in the material preparation step is matched to the planned clad surface of the corresponding base material. For example, the shape of clad material 32A matches the planned clad surface 31As of the base material 31A, and the shape of clad material 32B matches the planned clad surface 31Bs of the base material 31B. Specifically, a stainless steel material of uniform thickness can be bent to obtain the clad material with a shape that matches the planned clad surface of the corresponding base material.

[0084] Similarly, the shape, dimensions, and assembly method of the materials prepared during the clad material manufacturing stage affect the structural shape of the final stainless steel clad sheet.

[0085] In this embodiment, as shown in Figure 16, based on the arrangement of a base material with a non-monotonically varying thickness along the X direction, prepared in the material preparation step, and clad material 32A and clad material 32B as intermediate layers in the assembly step, the clad material of this embodiment, after going through the subsequent clad material rolling step and sheet product step, produces two stainless steel clad sheets in which the base material layer has a non-monotonically varying thickness along the X direction, and the four sides of the clad material layer and base material layer are flush.

[0086] For example, as shown in Figure 16, the obtained stainless steel clad sheet 30A is obtained by rolling its lower carbon steel base layer 31A and upper stainless steel clad layer 32A from the aforementioned base material 31A and clad material 32A, respectively, and therefore the original reference numerals for base material 31A and clad material 32A are continued to be used. Of these, the base material layer 31A has a thickness that varies along the X direction, specifically, the thickness varies non-monotonically along the X direction, and more specifically, the upper surface of the base material layer 31A includes at least two planes aligned along the X direction, five planes being illustrated in the figure. The four sides of the clad material layer 32A and the base material layer 31A are flush, and the clad material layer 32A just completely covers the upper surface of the base material layer 31A.

[0087] For example, as shown in Figure 16, the obtained stainless steel clad sheet 30B is obtained by rolling its lower carbon steel base layer 31B and upper stainless steel clad layer 32B from the aforementioned base material 31B and clad material 32B, respectively, so the original reference numerals for base material 31B and clad material 32B are continued to be used. Of these, the base material layer 31B has a thickness that varies along the X direction, specifically, its thickness varies non-monotonically along the X direction, and more specifically, the upper surface of the base material layer 31B includes at least two planes arranged along the X direction, five of which are illustrated in the figure. The four sides of the clad material layer 32B and the base material layer 31B are flush, and the clad material layer 32B just completely covers the upper surface of the base material layer 31B.

[0088] In general, a single-sided stainless steel clad sheet is provided, and the clad material manufactured according to this embodiment is produced through a clad material rolling stage and a sheet product stage. The clad sheet has a total thickness of (5~47)~(7~55) mm, a base material layer thickness of (4~37)~(6~45) mm, a clad material layer thickness of 1~10 mm, and is a non-uniform thickness sheet with a non-monotonically changing thickness along the X direction.

[0089] The steps in the manufacturing process of the clad material according to this embodiment have been described in detail above. In the several test examples described later, test examples 7 to 9 employ this embodiment to manufacture the clad material, and stainless steel clad plates were manufactured using the manufactured clad material. Here, Table 3 shows some of the parameters of the clad material in these examples, and please refer to the above explanation for the parameters indicated by the symbols.

[0090] [Table 3]

[0091] <Fourth embodiment of the clad material manufacturing stage> Referring to Figures 17 to 21, a fourth embodiment of the clad material manufacturing stage is shown. The differences between this embodiment and the first embodiment of the clad material manufacturing stage described above are the material preparation process, the separation agent application process, and the assembly process. On the other hand, the seal welding process, the vacuuming process, the sealing process, etc., are the same as in the first embodiment. Below, only the processes with differences will be described in detail, and other details will be omitted as they can be understood by referring to the drawings and the first embodiment of the clad material manufacturing stage described above.

[0092] In this embodiment, referring to Figure 17, the material preparation step specifically includes the following: Two carbon steel materials with dimensions L1 in the X direction and W1 in the Y direction are prepared and used as two base materials, which are distinguished as base material 41A and base material 41B in Figure 17. Furthermore, the thicknesses of base material 41A and base material 41B may be the same or different, and if they are set to different thicknesses, stainless steel clad plates of different thickness specifications can be manufactured accordingly. The cladding surfaces of each base material are polished; for example, the surface 41As of base material 41A and the surface 41Bs of base material 41B are polished to remove the oxide scale from the surface and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the cladding surface is less than 5 μm. A single stainless steel material with dimensions L22 in the X direction, W2 in the Y direction, and thickness T2 is prepared and used as a single clad material, which is clad material 42A in Figure 17, and one side A3s in the X direction of the clad material 42A is a hypotenuse with width V. A single stainless steel material with dimensions L21 in the X direction, W2 in the Y direction, and a thickness of T2 is prepared and used as another cladding material, which is cladding material 42B in Figure 17, and one side B3s in the X direction of cladding material 42B is a hypotenuse with a width V. One small surface in the thickness direction of each cladding material constitutes the non-cladding planned surface. For example, the surface A2s of the cladding material 42A and the surface B2s of the cladding material 42B, and the other large surface constitutes the cladding planned surface. For example, the surface A1s of the cladding material 42A and the surface B1s of the cladding material 42B. The cladding planned surfaces of each cladding material are polished to remove the oxide scale on the surface and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the cladding planned surface is less than 5 μm.

[0093] Based on the above dimensions, that is, the cladding material 42A and the cladding material 42B have the same dimension in the Y direction and the same thickness. On the other hand, the dimensions of the cladding material 42A and the cladding material 42B in the X direction may be the same (i.e., L21 = L22) or different (i.e., L21 ≠ L22). When L21 = L22, stainless steel clad plates with the same dimension specifications of the cladding material layer in the X direction can be manufactured accordingly. When L21 ≠ L22, stainless steel clad plates with different dimension specifications of the cladding material layer in the X direction can be manufactured accordingly.

[0094] Among them, the width V refers to the span width in the X direction of the hypotenuse. Due to the existence of the hypotenuse, on the two surfaces in the thickness direction of each cladding material, one surface becomes the large surface and the other surface becomes the small surface.

[0095] Also, L1 ≥ 2500 mm, W2 ≥ 1600 mm, T1 ≥ 60 mm. Regarding the dimension relationship between the cladding material 42A, the cladding material 42B and the base material 41A, the base material 41B, L₂₁ + L₂₂ - V < L₁, W₂ < W₁. More preferably, W₁ = W₂ + (90 - 150) mm, L₁ = L₂₁ + L₂₂ - V + (90 - 150) mm.

[0096] Preferably, the surface 41As of the base material 41A and the surface 41Bs of the base material 41B are polished respectively using a grinding machine, a belt sander or a milling machine to remove the oxide scale on the surface and expose the metallic luster. The surface A1s of the cladding material 42A and the surface B1s of the cladding material 42B are polished respectively using a wire brush to remove the oxide scale on the surface and expose the metallic luster.

[0097] While this description only covers surface polishing of the intended cladding surfaces of each base material and cladding material, surface polishing can also be performed on other surfaces of each base material and cladding material. Such additional surface polishing is not essential to achieving the technical effects of the present invention, but it may be preferable.

[0098] Furthermore, in this embodiment, the separation agent application step specifically includes applying the separation agent to the unclad surface and hypotenuse of each clad material. Specifically, for example, the separation agent is applied to the surface A2s and hypotenuse A3s of clad material 42A, and to the surface B2s and hypotenuse B3s of clad material 42B.

[0099] Regarding the components of the separating agent, the first option is a coating liquid containing silicon dioxide and magnesium oxide, with a mass ratio of silicon dioxide to magnesium oxide of 3:1. The separating agent of this embodiment can achieve a good separation effect and ensure the separation of the two subsequent clad plates. When using the separating agent, the amount of separating agent 43 applied to the planned clad surface and hypotenuse of each clad material is 20 y·mg / m². 2 Here, y is the ratio of the thickness of the clad material produced in the clad material manufacturing process to the thickness of the large clad plate produced by subsequent rolling, and this ratio is also called the clad material rolling compression ratio. The method for preparing the separating agent and the subsequent drying are the same as those described in the first embodiment of the clad material manufacturing stage described above, so a redundant explanation will be omitted.

[0100] As a second option for the components of the separating agent, the weight ratio is 25-35% silicon nitride + 5-10% thermosetting amino resin + 55-70% water. Compared to conventional separating agents, and even compared to the first embodiment of the separating agent described above, the separating agent of this embodiment achieves a good separation effect and can guarantee the separation of the two subsequent clad plates. Furthermore, the active ingredient silicon nitride has high chemical stability, excellent high temperature resistance and thermal shock resistance, and the thermosetting amino resin used as an adhesive can cure at low temperatures, is non-toxic, and can achieve a strong adhesive effect in small amounts. Therefore, overall, it is inexpensive, easy to operate, and has good separation and adhesion effects. When using the separating agent, the coating thickness of the separating agent 43 on the planned clad surface and hypotenuse of each clad material is 0.2-0.5 mm. The preparation method of the separating agent and the subsequent drying are the same as those described in the first embodiment of the clad material manufacturing stage described above, so redundant explanations are omitted.

[0101] Furthermore, in this embodiment, referring to Figure 18, the assembly process specifically involves using clad material 42A and clad material 42B as an intermediate layer, stacking base material 41A on top and base material 41B on the bottom, arranging four sealing materials 44 so as to surround the four sides of the intermediate layer, and then gas-shielding welding is performed between the upper end of the sealing material 44 and the base material 41A, and between the lower end of the sealing material 44 and the base material 41B to form a material assembly. In the intermediate layer, clad material 42A and clad material 42B are arranged in parallel along the X direction, and the hypotenuse A3s of clad material 42A and the hypotenuse B3s of clad material 42B are parallel to each other.

[0102] To make it easier to understand, in the material assembly obtained in the assembly process, the surface 41As of the base material 41A and the surface A1s of the cladding material 42A are in contact with each other as planned cladding surfaces, the surface 41Bs of the base material 41B and the surface B1s of the cladding material 42B are in contact with each other as planned cladding surfaces, and a separating agent is applied between the surface A2s of the cladding material 42A and the base material 41B, between the surface B2s of the cladding material 42B and the base material 41A, and between the hypotenuse A3s of the cladding material 42A and the hypotenuse B3s of the cladding material 42B. Although they are in contact with each other, no cladding occurs.

[0103] More preferably, in the assembly process, the base material 41A, clad material 42A and clad material 42B, base material 41B are stacked, and with the upper or lower end of the sealing material 44 not welded to the base material, the entire stacked steel material is placed under a four-column hydraulic press, and a pressure of 500 tons or more is applied to the opposite surfaces of the two base materials (i.e., the upper surface of base material 41A and the lower surface of base material 41B). This makes the contact between adjacent steel materials closer.

[0104] Preferably, during the assembly process, when gas shield welding is performed between the end of the seal material 44 and the base material, the welding current is controlled to 220-240A, the welding voltage to 28-32V, the welding speed to 300-360mm / min, and the interpass temperature to 140-160°C. In addition, before gas shield welding, the base materials 41A and 41B are preferably preheated and baked with a torch, with a baking temperature of 150-250°C.

[0105] Furthermore, grooves are formed on all four sides of the resulting material assembly, surrounded by the base material 41A, the sealing material 44, and the base material 41B. Preferably, the depth of the grooves on all four sides of the material assembly is set to be the same, and as shown in Figure 19, the depth D is in the range of 40 to 60 mm. This control of depth D not only effectively prevents cracks in the welded area during the rolling of the clad material, but also prevents the formation of thermal cracks during subsequent seal welding due to deeper penetration, which would affect the seal welding quality of the clad material.

[0106] To make it easier to understand, the groove depth depends on the dimensional difference between the cladding material and the base material in the X and Y directions, as well as the thickness of the sealant 44. For example, in the assembly process, the intermediate layer is centered relative to the base material, and the distance from two sides of the intermediate layer in the Y direction to the corresponding two sides of the base material is equal, between 45 and 75 mm, with the corresponding groove depth D = (W1 - W2 - 2T3) / 2. Similarly, the distance from two sides of the intermediate layer in the X direction to the corresponding two sides of the base material is also equal, between 45 and 75 mm, with the corresponding groove depth D = (L1 - (L21 + L22 - V) - 2T3) / 2. Of these, T3 is the thickness of the sealant, in the range of 10 to 15 mm.

[0107] Furthermore, regarding the overall dimensions of the four sealing materials 44, the length of the sealing material 44 is L31 = W2 to W2-2 mm on two sides in the X direction of the material assembly, and the length of the sealing material 44 is L32 = L21 + L22-V to L21 + L22-V-2 mm on two sides in the Y direction. The width W3 of the sealing material 44 is T2 to T2-2 mm, and the thickness T3 is 10 to 15 mm as described above. Preferably, the width W3 and thickness T3 of the sealing material 44 on all four sides of the material assembly are the same.

[0108] More preferably, as shown in Figure 19, grooves are provided at both the upper and lower ends of the outer surface of the seal material 44, with a groove angle of 10 to 20° and a groove vertical depth P of 10 to 15 mm. Providing grooves avoids spot welding processes on the inside of the seal material, prevents thermal effects on the base material due to multiple welds, facilitates subsequent seal welding grooves, and ensures rigidity.

[0109] Referring to Figure 19, the groove angle K1 at the upper end and the groove angle K2 at the lower end of the outer surface of the sealing material 44 are both 10 to 20°, and they may be the same or different.

[0110] Furthermore, a circular through-hole is provided in the sealing material on one side of the material assembly, and in this assembly process, a steel pipe 46 with an outer diameter r and a length T3+2D to T3+2D+R is welded to the through-hole. The through-hole may be processed before the gas shield welding of the sealing material 44 and the base materials 41A and 41B, or it may be processed after the gas shield welding is completed and the material assembly is formed. None of these methods deviate from the technical intent of this application.

[0111] Preferably, the diameter of the through hole matches the outer diameter of the steel pipe 46, and both are r.

[0112] More preferably, as shown in Figure 20, the through-hole is provided in the sealing material 44 on one of the short sides of the material assembly, and the through-hole is centered at a position that is 1 / 3 of the length and 1 / 2 of the width of the sealing material 44. Referring to Figure 20, the end face of the steel pipe 46 is flush with the inner surface of the sealing material 44. This ensures the effect of vacuuming.

[0113] What needs to be explained here is that, according to the example in the figure, the X direction is the length direction of the base material, and the Y direction is the width direction of the base material; that is, the two clad materials in the drawing are arranged in parallel between the two base materials along the length direction of the base material. Of course, in a modified embodiment, the X direction may be the width direction of the base material and the Y direction may be the length direction of the base material; that is, the two clad materials are arranged in parallel between the two base materials along the width direction of the base material.

[0114] Furthermore, as mentioned above, the shape, dimensions, and assembly method of the materials prepared during the clad material manufacturing stage affect the structural shape of the final stainless steel clad plate.

[0115] As shown in Figure 21, in this embodiment, based on the arrangement of clad material 42A and clad material 42B in parallel as an intermediate layer in the assembly process, the clad material of this embodiment, after going through the subsequent clad material rolling stage and plate product stage, results in two stainless steel clad plates in which the clad material layer covers only a portion of the upper surface of the base material layer, and does not cover the entire surface.

[0116] For example, the obtained stainless steel clad sheet 40A uses the same reference numerals as the original base material 41A and clad material 42A because its carbon steel base layer 41A and stainless steel clad layer 42A were obtained by rolling from the aforementioned base material 41A and clad material 42A, respectively. Three sides of the clad layer 42A are flush with the three sides of the base material layer 41A, while the other side of the clad layer 42A is located inside the upper surface of the base material layer 41A. As a result, the clad layer 42A covers only one end of the base material layer 41A, leaving the other end of the base material layer 41A exposed.

[0117] For example, the obtained stainless steel clad sheet 40B is obtained by rolling its carbon steel base layer 41B and stainless steel clad layer 42B from the aforementioned base material 41B and clad material 42B, respectively, and therefore the original reference numerals for base material 41B and clad material 42B are continued to be used. Three sides of the clad layer 42B are flush with the three sides of the base material layer 41B, while the other side of the clad layer 42B is located inside the upper surface of the base material layer 41B. As a result, the clad layer 42B covers only one end of the base material layer 41B, leaving the other end of the base material layer 41B exposed.

[0118] The beneficial effects of the clad plates manufactured using the clad material of this embodiment need to be understood in conjunction with the current usage of existing stainless steel clad plates in bridge construction. Specifically, stainless steel clad plates for bridge structures need to be butt-jointed with bridge structural steel plates during the processing and use process at downstream structural factories. At this joint, the base material layer of the stainless steel clad plate and the bridge structural steel plate are of the same material, and the welding strength can be easily guaranteed. However, the stainless steel clad material layer and the bridge structural steel plate are of different materials, making welding difficult and resulting in inferior rigidity, which has a certain impact on the safety of the overall structural member. On the other hand, the clad plates manufactured using the clad material of this embodiment have a clad structure at one end composed of carbon steel and stainless steel (for example, the left end of clad plates 40A and 40B in Figure 21), and this end combines the corrosion resistance of the clad material layer with the excellent mechanical properties of the base material layer, similar to existing clad plates. The other end is made of pure carbon steel (for example, the right end of clad plates 40A and 40B in Figure 21), which allows this stainless steel clad plate to avoid existing dissimilar welding problems during use, resulting in high rigidity during use, low production difficulty in later stages of use, low cost, and high construction efficiency.

[0119] More preferably, the side of the clad layer 42A that is "located inside the upper surface of the base layer 41A" is set as a hypotenuse, and this hypotenuse forms an obtuse angle with the upper surface of the clad layer 42A. Similarly, the side of the clad layer 42B that is "located inside the upper surface of the base layer 41B" is set as a hypotenuse, and this hypotenuse forms an obtuse angle with the upper surface of the clad layer 42B. In contrast, when applying existing clad plates to bridge construction, an additional stainless steel plate is required to transition between the end of the stainless steel clad layer and the structural steel plate of the bridge in order to avoid a step (height difference), which not only incurs additional material costs, but this additional stainless steel plate also needs to be welded to both the clad layer of the stainless steel clad plate and the structural steel plate of the bridge, which significantly increases the amount of welding work and affects construction efficiency. On the other hand, in this embodiment, there is no step between the end of the stainless steel clad layer and the structural steel plate of the bridge, the transition is at an incline, an additional transition plate is not required, construction efficiency is high, the amount of work is low, and structural strength is high.

[0120] In general, a single-sided stainless steel clad sheet is provided, and the clad material manufactured according to this embodiment is produced through a clad material rolling stage and a sheet product stage. The total thickness of the clad sheet is 5 to 55 mm, the base material layer thickness is 4 to 45 mm, and the clad material layer thickness is 1 to 10 mm, with one end in the X direction covered and the other end uncovered.

[0121] The steps in the manufacturing process of the clad material according to this embodiment have been described in detail above. In the several test examples described later, test examples 10 to 12 employ this embodiment to manufacture the clad material, and stainless steel clad plates were manufactured using the manufactured clad material. Here, Table 4 shows some of the parameters of the clad material in these embodiments, and please refer to the above explanation for the parameters indicated by the symbols.

[0122] [Table 4]

[0123] <Fifth embodiment of the clad material manufacturing stage> Referring to Figures 22 to 26, a fifth embodiment of the clad material manufacturing stage is shown. The differences between this embodiment and the first embodiment of the clad material manufacturing stage described above are the material preparation process, the separation agent application process, and the assembly process. On the other hand, the seal welding process, the vacuuming process, the sealing process, etc., are the same as in the first embodiment. Below, only the processes with differences will be described in detail, and other details will be omitted as they can be understood by referring to the drawings and the first embodiment of the clad material manufacturing stage described above.

[0124] In this embodiment, referring to Figure 22, the material preparation step specifically includes the following: Two carbon steel materials with dimensions L1 in the X direction and W1 in the Y direction are prepared and used as two base materials, which are distinguished as base material 51A and base material 51B in Figure 22. The thicknesses of base material 51A and base material 51B may be the same or different. The cladding surfaces of each base material are polished; for example, the surface 51As of base material 51A and the surface 51Bs of base material 51B are polished to remove the oxide scale from the surface and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the cladding surface is less than 5 μm. A single stainless steel material with dimensions L22 in the X direction, W2 in the Y direction, and thickness T2 is prepared and used as a single clad material, which is clad material 52A in Figure 22. One side A3s in the X direction of clad material 52A is a hypotenuse with width V1, and the other side A4s in the X direction is a hypotenuse with width V2. A single stainless steel material with dimensions L21 in the X direction, W2 in the Y direction, and a thickness of T2 is prepared and used as another clad material, which is clad material 52B in Figure 22, and one side B3s in the X direction of clad material 52B is a hypotenuse with a width of V1. A single stainless steel material with dimensions L23 in the X direction, W2 in the Y direction, and a thickness of T2 is prepared and used as another clad material, which is clad material 52C in Figure 22, and one side C3s in the X direction of clad material 52C is a hypotenuse with a width of V2. One small surface in the thickness direction of each clad material constitutes a non-clad surface, for example, surface A2s of clad material 52A, surface B2s of clad material 52B, and surface C2s of clad material 52C, while another large surface constitutes a clad surface, for example, surface A1s of clad material 52A, surface B1s of clad material 52B, and surface C1s of clad material 52C. The clad surfaces of each clad material are polished to remove surface oxide scale and expose the metallic luster. After the surface polishing treatment, the roughness Ra of the clad surface is less than 5 μm.

[0125] Based on the above dimensions, that is, clad material 52A, clad material 52B, and clad material 52C have the same dimensions in the Y direction and the same thickness. On the other hand, the dimensions in the X direction of clad material 52A, clad material 52B, and clad material 52C may all be the same (i.e., L21=L23=L22), two of them may be the same (i.e., L21=L23≠L22, or L21≠L23=L22, or L21=L22≠L23), or they may all be different (i.e., L21≠L22≠L23).

[0126] Of these, widths V1 and V2 refer to the span width of the hypotenuse in the X direction. Due to the presence of the hypotenuse, on the two surfaces in the thickness direction of each clad material, one surface becomes a larger surface and the other surface becomes a smaller surface. Also, both side A3s of clad material 52A and side B3s of clad material 52B are hypotenuses with width V1, and as a result, as will be described in the subsequent assembly process, side A3s and side B3s are joined parallel to each other. Similarly, both side A4s of clad material 52A and side C3s of clad material 52C are hypotenuses with width V2, and as a result, as will be described in the subsequent assembly process, side A3s and side B3s are joined parallel to each other.

[0127] Preferably, both the side A3s and side A4s of the clad material 52A form an obtuse angle with the unclad surface A2s of the clad material 52A.

[0128] Also, L1 ≥ 2500 mm, W2 ≥ 1600 mm, T1 ≥ 60 mm. Regarding the dimensional relationship between the clad materials 52A, 52B, 52C and the base materials 51A, 51B, L21 + L22 + L23 - V1 - V2 < L1, W2 < W1, and more preferably, W1 = W2 + (90 - 150) mm, L1 = L21 + L22 + L23 - V1 - V2 + (90 - 150) mm.

[0129] Preferably, the surfaces 51As of the base material 51A and 51Bs of the base material 51B are polished using a grinding machine, a belt sander, or a milling machine respectively to remove the surface oxide scale and expose the metallic luster. The surfaces A1s of the clad material 52A, B1s of the clad material 52B, and C1s of the clad material 52C are polished using a wire brush respectively to remove the surface oxide scale and expose the metallic luster.

[0130] Here, only the surface polishing treatment of each base material and the planned clad surface of each clad material has been described, but the surface polishing treatment can also be performed on other surfaces of each base material and clad material. Such additional surface polishing treatments are not essential for realizing the technical effects of the present invention, but there may be more preferable cases.

[0131] Furthermore, in the present embodiment, the release agent application step specifically includes applying a release agent to the non-clad planned surfaces and the bevel edges of each clad material. Specifically, for example, a release agent is applied to the surface A2s, bevel edges A3s and A4s of the clad material 52A, the surface B2s and bevel edge B3s of the clad material 52B, and the surface C2s and bevel edge C3s of the clad material 52C.

[0132] Regarding the composition of the release agent, as a first option, it is a coating liquid containing silicon dioxide and magnesium oxide, and the mass ratio of silicon dioxide to magnesium oxide is 3:1. The release agent of the present embodiment can achieve a good separation effect and ensure the separation of the subsequent two small clad plates. When using the release agent, the application amount of the release agent 53 on the clad planned surfaces and bevel edges of each clad material is 20y·mg / m 2Here, y is the ratio of the thickness of the clad material produced in the clad material manufacturing process to the thickness of the large clad plate produced by subsequent rolling, and this ratio is also called the clad material rolling compression ratio. The method for preparing the separating agent and the subsequent drying are the same as those described in the first embodiment of the clad material manufacturing stage described above, so a redundant explanation will be omitted.

[0133] As a second option for the components of the separating agent, the weight ratio is 25-35% silicon nitride + 5-10% thermosetting amino resin + 55-70% water. Compared to conventional separating agents, and even compared to the first embodiment of the separating agent described above, the separating agent of this embodiment achieves a good separation effect and can guarantee the separation of the two subsequent clad plates. Furthermore, the active ingredient silicon nitride has high chemical stability, excellent high temperature resistance and thermal shock resistance, and the thermosetting amino resin used as an adhesive can cure at low temperatures, is non-toxic, and can achieve a strong adhesive effect in small amounts. Therefore, overall, it is inexpensive, easy to operate, and has good separation and adhesion effects. When using the separating agent, the coating thickness of the separating agent 53 on the planned clad surface and hypotenuse of each clad material is 0.2-0.5 mm. The preparation method of the separating agent and the subsequent drying are the same as those described in the first embodiment of the clad material manufacturing stage described above, so redundant explanations are omitted.

[0134] Furthermore, in this embodiment, referring to Figure 23, the assembly process specifically involves using clad material 52A, clad material 52B, and clad material 52C as an intermediate layer, stacking base material 51A on top and base material 51B on the bottom, arranging four seal materials 54 to surround the four sides of the intermediate layer, and then gas-shielding welding is performed between the upper end of the seal material 54 and the base material 51A, and between the lower end of the seal material 54 and the base material 51B to form a material assembly. In the intermediate layer, clad material 52B, clad material 52A, and clad material 52C are arranged in parallel in sequence along the X direction, the hypotenuse A3s of clad material 52A and the hypotenuse B3s of clad material 52B are joined parallel to each other, and the hypotenuse A4s of clad material 52A and the hypotenuse C3s of clad material 52C are joined parallel to each other.

[0135] To make it easier to understand, in the material assembly obtained in the assembly process, the surface 51As of the base material 51A and the surface A1s of the clad material 52A are in contact with each other as clad surfaces, the surface 51Bs of the base material 51B and the surface B1s of the clad material 52B are in contact with each other as clad surfaces, the surface 51Bs of the base material 51B is also in contact with the surface C1s of the clad material 52C as a clad surface, and a separating agent is applied between the surface A2s of the clad material 52A and the base material 51B, between the surface B2s of the clad material 52B and the base material 51A, between the surface C2s of the clad material 52C and the base material 51A, between the hypotenuse A3s of the clad material 52A and the hypotenuse B3s of the clad material 52B, and between the hypotenuse A4s of the clad material 52A and the hypotenuse C3s of the clad material 52C. Although these surfaces are in contact with each other, no cladding occurs.

[0136] More preferably, in the assembly process, the base material 51A, clad material 52B, clad material 52A and clad material 52C, and base material 51B are stacked, and with the upper or lower end of the sealing material 54 not welded to the base material, the entire stacked steel material is placed under a four-column hydraulic press, and a pressure of 500 tons or more is applied to the opposite surfaces of the two base materials (i.e., the upper surface of base material 51A and the lower surface of base material 51B). This makes the contact between adjacent steel materials closer.

[0137] Preferably, during the assembly process, when gas shield welding is performed between the end of the seal material 54 and the base material, the welding current is controlled to 220-240A, the welding voltage to 28-32V, the welding speed to 300-360mm / min, and the interpass temperature to 140-160°C. In addition, before gas shield welding, the base materials 51A and 51B are preferably preheated and baked with a torch, with a baking temperature of 150-250°C.

[0138] Furthermore, grooves are formed on all four sides of the resulting material assembly, surrounded by the base material 51A, the sealing material 54, and the base material 51B. Preferably, the depth of the grooves on all four sides of the material assembly is set to be the same, and as shown in Figure 24, the depth D is in the range of 40 to 60 mm. This control of depth D not only effectively prevents cracks in the welded area during the rolling of the clad material, but also prevents the formation of thermal cracks during subsequent seal welding due to deeper penetration, which would affect the seal welding quality of the clad material.

[0139] To make it easier to understand, the groove depth depends on the dimensional difference between the cladding material and the base material in the X and Y directions, as well as the thickness of the sealant 54. For example, in the assembly process, the intermediate layer is centered relative to the base material, and the distance from two sides of the intermediate layer in the Y direction to the corresponding two sides of the base material is equal, and this distance is 45 to 75 mm, with the corresponding groove depth D = (W1 - W2 - 2T3) / 2. Similarly, the distance from two sides of the intermediate layer in the X direction to the corresponding two sides of the base material is also equal, and this distance is 45 to 75 mm, with the corresponding groove depth D = (L1 - (L21 + L22 + L23 - V1 - V2) - 2T3) / 2. Of these, T3 is the thickness of the sealant, and is in the range of 10 to 15 mm.

[0140] Furthermore, regarding the overall dimensions of the four sealing materials 54, on two sides in the X direction of the material assembly, the length of the sealing material 54 L31 = W2 ~ W2 - 2 mm, and on two sides in the Y direction, the length of the sealing material 54 L32 = L21 + L22 + L23 - V1 - V2 ~ L21 + L22 + L23 - V1 - V2 - 2 mm. The width W3 of the sealing material 54 = T2 ~ T2 - 2 mm, and the thickness T3 is 10 ~ 15 mm as described above. Preferably, the width W3 of the sealing material 54 on all four sides of the material assembly is the same, and the thickness T3 is also the same.

[0141] More preferably, as shown in Figure 24, grooves are provided at both the upper and lower ends of the outer surface of the seal material 54, with a groove angle of 10 to 20° and a groove vertical depth P of 10 to 15 mm. Providing grooves avoids the spot welding process on the inside of the seal material, prevents thermal effects on the base material due to multiple welds, facilitates subsequent seal welding grooves, and ensures rigidity.

[0142] Referring to Figure 24, the groove angle K1 at the upper end and the groove angle K2 at the lower end of the outer surface of the sealing material 54 are both 10 to 20°, and they may be the same or different.

[0143] Furthermore, a circular through-hole is provided in the sealing material on one side of the material assembly, and in this assembly process, a steel pipe 56 with an outer diameter r and a length T3+2D to T3+2D+R is welded to the through-hole. The through-hole may be processed before the gas shield welding of the sealing material 54 and the base materials 51A and 51B, or it may be processed after the gas shield welding is completed and the material assembly is formed. None of these methods deviate from the technical intent of this application.

[0144] Preferably, the diameter of the through hole matches the outer diameter of the steel pipe 56, and both are r.

[0145] More preferably, as shown in Figure 25, the through-hole is provided in the sealant 54 on one of the short sides of the material assembly, and the through-hole is centered at a position that is 1 / 3 of the length and 1 / 2 of the width of the sealant 54. Referring to Figure 24, the end face of the steel pipe 56 is flush with the inner surface of the sealant 54. This ensures the effect of vacuuming.

[0146] What needs to be explained here is that, according to the example in the figure, the X direction is the length direction of the base material, and the Y direction is the width direction of the base material; that is, the three clad materials in the drawing are arranged in parallel between two base materials along the length direction of the base material. Of course, in a modified embodiment, the X direction may be the width direction of the base material and the Y direction may be the length direction of the base material; that is, the three clad materials are arranged in parallel between two base materials along the width direction of the base material.

[0147] Furthermore, as mentioned above, the shape, dimensions, and assembly method of the materials prepared during the clad material manufacturing stage affect the structural shape of the final stainless steel clad plate.

[0148] As shown in Figure 26, in this embodiment, based on the sequential arrangement of clad material 52B, clad material 52A, and clad material 52C as intermediate layers in the assembly process, the clad material of this embodiment, after going through the subsequent clad material rolling stage and plate product stage, will have at least two of the three stainless steel clad plates manufactured having the clad material layer covering only a portion of the upper surface of the base material layer, and not the entire surface.

[0149] For example, as shown in Figure 26, the obtained stainless steel clad sheet 50A is obtained by rolling its carbon steel base layer 51A and stainless steel clad layer 52A from the aforementioned base material 51A and clad material 52A, respectively, and therefore the original reference numerals for base material 51A and clad material 52A are continued to be used. Of these, two sides of the clad layer 52A in the Y direction are flush with the corresponding two sides of the base material layer 51A, while both sides of the clad layer 52A in the X direction are located inside the upper surface of the base material layer 51A. As a result, the clad layer 52A covers only the central region of the base material layer 51A, leaving both ends of the base material layer 51A in the X direction exposed. This type of clad sheet can be called a central stainless steel clad sheet. Thus, the central part of this stainless steel clad sheet is a clad structure composed of a carbon steel base layer 51A and a stainless steel clad material layer 52A, and like existing clad sheets, it combines the corrosion resistance of the clad material layer 52A with the excellent mechanical properties of the base layer 51A. On the other hand, both ends of the stainless steel clad sheet are pure carbon steel base layers 51A and are directly integrally molded with the clad structure, so these carbon steel base layers 51A at both ends can be used directly in construction and welding can be omitted. As a result, this stainless steel clad sheet avoids the existing dissimilar welding problems during use, has high rigidity during use, is easy to produce, has low cost, and has high construction efficiency.

[0150] Furthermore, both sides of the clad material layer 52A in the X direction are set as hypotenuses, and these two hypotenuses form an obtuse angle with the upper surface of the clad material layer 52A. In contrast, when applying existing clad plates to bridge construction, it is necessary to use additional stainless steel plates to avoid the step (height difference) between the end of the stainless steel clad material layer and the structural steel plate of the bridge. This not only incurs additional material costs, but also requires welding of this additional stainless steel plate to both the clad material layer of the stainless steel clad plate and the structural steel plate of the bridge, significantly increasing the amount of welding work and affecting construction efficiency. On the other hand, in this embodiment, there is no step between the end of the stainless steel clad material layer and the structural steel plate of the bridge, the transition is at an incline, no additional transition plates are required, construction efficiency is high, the amount of work is low, and structural strength is high.

[0151] For example, as shown in Figure 26, the obtained stainless steel clad plates 50B and 50C are obtained by rolling their respective stainless steel clad layers 52B and 52C from the aforementioned clad materials 52B and 52C, and therefore the reference numerals for clad materials 52B and 52C are continued to be used. On the other hand, the original base material 51B is divided into two parts by rolling and cutting, with one part becoming the base material layer 51Ba of clad plate 50B and the other part becoming the base material layer 51Bc of clad plate 50C.

[0152] In the illustration, in the stainless steel clad plate 50B, three sides of the clad material layer 52B are flush with three sides of the base material layer 51Ba, while the other side of the clad material layer 52B is located inside the upper surface of the base material layer 51Ba. As a result, the clad material layer 52B covers only one end of the base material layer 51Ba (for example, the left end in Figure 26), leaving the other end of the base material layer 51Ba (for example, the right end in Figure 26) exposed. Similarly, in the stainless steel clad plate 50C, three sides of the clad material layer 52C are flush with three sides of the base material layer 51Bc, while the other side of the clad material layer 52C is located inside the upper surface of the base material layer 51Bc. As a result, the clad material layer 52C covers only one end of the base material layer 51Bc (for example, the right end in Figure 26), leaving the other end of the base material layer 51Bc (for example, the left end in Figure 26) exposed. Thus, clad plates 50B and 50C have a clad structure at one end composed of carbon steel and stainless steel, and this end combines the corrosion resistance of the clad material layer with the excellent mechanical properties of the base material layer, similar to existing clad plates. On the other hand, the other end is a pure carbon steel plate, which avoids the existing dissimilar welding problems in use, resulting in high rigidity during use, low production difficulty in later use, low cost, and high construction efficiency.

[0153] More preferably, the side of the clad layer 52B that is "located inside the upper surface of the base layer 51Ba" is set as a hypotenuse, and this hypotenuse forms an obtuse angle with the upper surface of the clad layer 52B. Similarly, the side of the clad layer 52C that is "located inside the upper surface of the base layer 51Bc" is set as a hypotenuse, and this hypotenuse forms an obtuse angle with the upper surface of the clad layer 52C. As a result, there is no step between the end of the stainless steel clad layer and the steel plate for the bridge structure, the transition is at an incline, no additional transition plates are required, construction efficiency is high, the amount of work is reduced, and structural strength is high.

[0154] To make it easier to understand, when rolling and cutting the original base material 51B into two parts, depending on the cutting position, one of the resulting clad plates can be a fully covered clad plate (for example, clad plate 10B shown in Figure 6) with the clad material layer and base material layer having the same length and width, while the other clad plate can be a clad plate where one end of the base material layer is covered by the clad material layer and the other end is not covered. Of course, other cutting methods can be used as required.

[0155] Thus, in this embodiment, at least two different types of cladding can be obtained simultaneously, resulting in superior industrial value.

[0156] Furthermore, while the fourth and fifth embodiments described above introduced assembly methods in which two and three clad materials are arranged in parallel, respectively, the present invention is not limited thereto, and assembly methods in which multiple clad materials are arranged in parallel are also possible.

[0157] In general, a single-sided stainless steel clad sheet is provided, and the clad material manufactured according to this embodiment is produced through a clad material rolling stage and a sheet product stage. The total thickness of the clad sheet is 5 to 55 mm, the base material layer thickness is 4 to 45 mm, and the clad material layer thickness is 1 to 10 mm, with the central region in the X direction covered and both ends uncovered. Of course, another single-sided stainless steel clad sheet can also be provided at the same time, and this too is produced through a clad material rolling stage and a sheet product stage using the clad material manufactured according to this embodiment. The total thickness of the clad sheet is 5 to 55 mm, the base material layer thickness is 4 to 45 mm, and the clad material layer thickness is 1 to 10 mm, with one end in the X direction covered and the other end uncovered.

[0158] The steps in the manufacturing process of the clad material according to this embodiment have been described in detail above. In the several test examples described later, test examples 13 to 15 employ this embodiment to manufacture the clad material, and stainless steel clad plates were manufactured using the manufactured clad material. Here, Table 5 shows some of the parameters of the clad material in these examples, and please refer to the above explanation for the parameters indicated by the symbols.

[0159] [Table 5]

[0160] The five embodiments of the clad material manufacturing stage have been described above. Next, specific embodiments of the clad material rolling stage and the sheet product stage will be described in detail. It is necessary to explain here that the specific embodiments of the clad material rolling stage and the sheet product stage described below are applicable to any of the five embodiments of the clad material manufacturing stage described above. That is, a clad material manufactured by any of the five embodiments of the clad material manufacturing stage described above can be manufactured into a single-sided stainless steel clad sheet by the specific embodiments of the clad material rolling stage and the sheet product stage described below.

[0161] Regarding the clad material rolling stage, the clad material produced in the clad material manufacturing stage is subjected to heating, rolling, and cooling processes to produce large clad plates. Each process is described in detail below.

[0162] First, regarding the heating process, the clad material is heated in a heating furnace to prepare for the subsequent rolling process. Specifically, this can be carried out using techniques known in this field.

[0163] This application provides a preferred embodiment of the heating process, specifically, the clad material is heated in a heating furnace in a five-stage manner: a preheating stage, a first heating stage, a second heating stage, a third heating stage, and a soaking stage, with the preheating stage temperature being ≤ 850°C, the first heating stage temperature being 1080±30°C, the second heating stage temperature being 1160±30°C, the third heating stage temperature being 1220±20°C, and the soaking stage temperature being 1190±20°C. The holding time for the third heating stage is (0.25~0.35) × t min / mm (where t is the thickness of the clad material), and the holding time for the soaking stage is 15 min to 30 min. Thus, the clad material consists of a stainless steel clad layer in the middle and a carbon steel base layer in the top and bottom. The differences in thermal conductivity and coefficient of thermal expansion between the two materials are significant, and large stresses may occur during the heating process. However, the heating process in this embodiment appropriately controls the heating rate at each stage of the clad material, ensuring uniform heating, thereby avoiding risks such as cracks and air leaks, and ultimately achieving an excellent bonding interface in the resulting clad plate.

[0164] Furthermore, in the rolling process, the clad material coming out of the heating furnace is rolled to produce large clad plates.

[0165] In one embodiment, the first n passes of the entire rolling process are performed using widthwise rolling, and the (n+1)th and subsequent passes are performed using longitudinal rolling. The reduction amount of the first pass is ≥ 25 mm and the rolling temperature is ≥ 1060°C. The width of the material after the nth pass is Wt + (0~40) mm (Wt is the target width of the clad plate). The rolling temperature of the nth pass is ≥ 1030°C. Between the nth and (n+1)th passes and between the (n+2)th and (n+3)th passes, the material is water-cooled once in a reciprocating cycle using six sets of headers, with an upper header cooling water volume of 120~180 m³ for each header. 3 / h, lower header cooling water volume 160~220m 3The rolling process is as follows: the roller conveyor speed is 0.8 to 1.2 m / s, the reduction amount for the (n+1)th to (n+3)th passes is all ≥ 40 mm, the reduction amount for the (n+2)th pass is preferably ≥ 42 mm, the rolling temperature for the (n+1)th pass is ≥ 950°C, and by the mth pass, the material is rolled to a rolling temperature of ≥ 900°C and a thickness of 2.5 to 3.5 times the target thickness of the clad plate. After that, water cooling is performed to cool the material until the surface temperature is 840°C or lower. Then, a second stage of rolling is performed, and the material is rolled until the thickness is the target thickness of the clad plate, completing the entire rolling process. The first pass rolling temperature of the second stage of rolling is 810°C to 840°C, and the final pass rolling temperature is 780°C to 810°C.

[0166] Thus, the rolling process of this embodiment ensures, on the one hand, the deformation penetration effect in the center, promotes bonding between the clad material and the base material, and improves the interfacial bonding rate and bonding strength between the base material layer and the clad material layer of the final clad plate; on the other hand, it guarantees the related mechanical performance, corrosion resistance, and low-temperature impact toughness of the large clad plate and prevents performance degradation due to the composite of the base material and the clad material.

[0167] The subsequent cooling process, specifically the process of cooling the high-temperature clad plate obtained in the rolling process, involves, specifically, after the aforementioned "final pass rolling temperature is 780-810°C," the temperature of the obtained clad plate when it leaves the rolling mill is around 780°C, after which it is cooled to room temperature. Specifically, existing practical cooling technologies can be used for cooling, but in one preferred embodiment of the present invention, a cooling process including an intermittent cooling technology is provided, which can have superior beneficial effects compared to existing cooling technologies.

[0168] Specifically, in this preferred embodiment, the cooling process includes intermittent cooling by entering an ultra-rapid cooling system after the clad plate leaves the rolling mill. The ultra-rapid cooling system has 24 sets of cooling headers arranged at 1m intervals along a roller conveyor. In the intermittent cooling, the cooling distance of each cooling header is 1m, and the opening and closing state of all 24 sets of cooling headers is controlled in such a manner that N sets of cooling headers are opened and then M sets of cooling headers are not opened as the clad plate passes through the ultra-rapid cooling system. The cooling water pressure is 0.15~0.30 MPa, the cooling rate is 3~15°C / s, and the final cooling temperature is 380~590°C. N takes a value of 2, 3, or 4, and M takes a value of 2, 3, or 4.

[0169] In this embodiment, by employing the intermittent cooling method described above, as the clad plate passes through the ultra-rapid cooling system, it moves between alternately open and closed cooling headers. This causes each part of the clad plate to cycle through cooling, red-hot recovery, cooling, red-hot recovery, and so on, until the clad plate leaves the ultra-rapid cooling system. In this way, within the cooling-red-hot recovery cycle, the carbon steel base material continuously undergoes phase transformation and self-tempering effects, and the phase transformation reaction gradually penetrates to the center, ultimately completing the phase transformation of the entire carbon steel base material. Unlike conventional reciprocating cooling, this intermittent cooling process occurs after phase transformation is complete at or near the surface, resulting in large temperature and cooling rate differences between the surface and the core, and significant differences in structure and mechanical properties. However, in this embodiment, a portion of the clad plate is cooled at the same time, while other portions are in a red-hot / self-tempered state. Furthermore, each part of the clad plate alternates between cooling and red-hot / self-tempering over time. As a result, the differences in temperature, cooling rate, structure, and performance between the surface and the core of the clad plate are small. For example, the difference in Vickers hardness in the thickness direction of the base material layer of the final clad plate is ≤10, the strength difference between the front, middle, and rear is ≤40 MPa, and the strength difference between all parts of the plate is ≤40 MPa. Simultaneously, intermittent cooling further improves the shape, i.e., flatness, of the clad plate, and even if the plate is cooled directly on a cooling bed without straightening after the cooling is complete, an excellent plate shape can be obtained.

[0170] More preferably, in the intermittent cooling described above, When the thickness of the clad plate is 54 mm or less, for example, 10 to 54 mm, the roller conveyor speed of the ultra-rapid cooling system is 0.4 to 0.8 m / s, and the clad plate leaves the ultra-rapid cooling system after passing through it once. Preferably, a preferred control scheme for the 24 sets of cooling headers is, for example, to open the first to fourth sets of cooling headers, not to open the fifth to sixth sets of cooling headers, to open the seventh to eighth sets of cooling headers, not to open the ninth to tenth sets of cooling headers, to open the eleventh to twelfth sets of cooling headers, not to open the thirteenth to fourteenth sets of cooling headers, to open the fifteenth to sixteenth sets of cooling headers, not to open the seventeenth to eighteenth sets of cooling headers, to open the nineteenth to twentyth sets of cooling headers, not to open the twenty-first to twenty-second sets of cooling headers, and to open the twenty-third to twenty-fourth sets of cooling headers. If the thickness of the clad plate is greater than 54 mm but less than 70 mm, the roller conveyor speed of the ultra-rapid cooling system is 0.2 m / s or more and less than 0.6 m / s, and the clad plate passes through the ultra-rapid cooling system once before leaving it. If the thickness of the clad plate is greater than or equal to 70 mm, the roller conveyor speed of the ultra-rapid cooling system is 0.4 to 0.9 m / s, the clad plate first enters the ultra-rapid cooling system inlet from the forward direction, and when its leading edge reaches the 24th set of cooling headers, the roller conveyor is reversed, and the clad plate passes through the ultra-rapid cooling system in the reverse direction and leaves the ultra-rapid cooling system inlet. In cases where the thickness of the cladding plate exceeds 54 mm, preferably, a preferred control scheme for the 24 sets of cooling headers is, for example, to open the first to fourth sets of cooling headers, not to open the fifth to eighth sets of cooling headers, to open the ninth to twelfth sets of cooling headers, not to open the thirteenth to sixteenth sets of cooling headers, to open the seventeenth to twenty sets of cooling headers, not to open the twenty-first to twenty-second sets of cooling headers, and to open the twenty-third to twenty-fourth sets of cooling headers.

[0171] Thus, intermittent cooling makes it possible to control the shape and uniformity of clad plates, especially when the thickness of the plate is large (for example, between 54 mm and 70 mm), and even larger (for example, ≥ 70 mm), thereby overcoming the challenges in the production of existing stainless steel clad plates.

[0172] Furthermore, in one embodiment, the cooling step specifically includes placing the clad plate, which has been removed from the ultra-rapid cooling system, directly onto a cooling bed and air-cooling it to room temperature. In a more preferred alternative embodiment, the clad plate, after being removed from the ultra-rapid cooling system, may first be cooled by stacking rather than being placed directly onto a cooling bed, for example, the cooling step specifically includes cooling the clad plate, which has been removed from the ultra-rapid cooling system, to temperature T f -150℃~T f The clad plate is placed between two steel plates at +150°C and cooled by stacking, with a stacking cooling time of 0.4 min / mm × t0 ± 5 min (where t0 is the thickness of the large clad plate). After the stacking cooling is complete, the large clad plate is placed on a cooling bed and allowed to cool naturally to room temperature. f =550+30Si-20Mn+15Cr-15Ni+10Mo, where the element symbols represent 100 times the mass percentage of each element in the base material. In this way, stacking cooling, especially controlling the temperature of the steel plate used for stacking cooling, provides a foundation for guaranteeing the performance of the clad plate. This involves making the temperature uniform in the thickness direction of the entire clad plate, preventing situations where the base material temperature is low and the clad material temperature is high, keeping the difference in expansion between the base material and the clad material small, and thereby guaranteeing the shape of the clad plate.

[0173] The clad material rolling step has been described in detail above. Next, the manufacturing method of the present invention further includes a sheet product step, and as described above, the sheet product step includes a cutting step and a planarization step.

[0174] Specifically, in the cutting process, a large clad plate that has been air-cooled to room temperature is cut along all four sides using a plasma cutter to remove the non-sealing material, separating the large clad plate into two smaller clad plates, one above the other. The two resulting smaller clad plates can then be flattened to produce two single-sided stainless steel clad plates. Of course, the two smaller clad plates can be further cut to produce even more single-sided stainless steel clad plates, such as the three stainless steel clad plate products introduced in the fifth embodiment of the clad material preparation stage described above, stainless steel clad plates 50A, 50B, and 50C in Figure 26.

[0175] Of these, the "parts other than the sealing material" refer to the edges of the large clad plate that have changed from the sealing material and filling layer in the clad material mentioned in the preceding paragraph after the rolling process. In this way, by removing this part and exposing the stainless steel clad material layer, the large clad plate automatically separates into two smaller clad plates, upper and lower, without any bonding action in this part.

[0176] Next, the planarization process specifically involves placing the single-sided clad plate obtained in the cutting process on a planarization machine with the clad material layer facing upwards and performing planarization. During planarization in the width direction, the planarization force F1 = ν × a × b × c T ×σ T / (d×(ν-c T Control to / a). When flattening in the longitudinal direction, the flattening force F2 of the flattening machine is a × b × c V ×σ V / (d+c V ) is controlled to the following: a is the width of the clad plate (unit: mm), b is the thickness of the clad plate (unit: mm), c T This refers to the flatness per meter in the width direction of the clad plate subfloor (unit: mm), c V σ is the flatness per meter in the longitudinal direction of the clad plate (unit: mm), d is the working distance of the flattening machine, σ T The tensile yield strength in the width direction of the clad plate is σ V ν is the longitudinal tensile yield strength of the clad plate, and ν is Poisson's ratio. By adjusting the planarization force and planarization direction in this way, an even better plate shape can be secured.

[0177] Finally, after the flattening process, a single-sided stainless steel clad plate product is obtained.

[0178] Furthermore, one embodiment of the present invention also provides a single-sided stainless steel clad sheet, manufactured by the manufacturing method described above, and comprising a base material layer modified from the base material and a clad material layer modified from the clad material.

[0179] Preferably, the clad material / clad layer is austenitic stainless steel. Its chemical composition, by mass percentage, is C ≤ 0.15%, Si ≤ 1.00%, Mn ≤ 2.00%, P ≤ 0.045%, S ≤ 0.030%, Ni: 6.0-22.0%, Cr: 16.0-26.0%, Mo ≤ 3.0%, with the remainder being Fe and unavoidable impurities.

[0180] As a preferred option, the chemical composition of the base material / base material layer is, by mass percentage, C: 0.03-0.16%, Si: 0.11-0.29%, Mn: 1.31-1.54%, P ≤ 0.018%, S ≤ 0.0030%, Cr: 0.06-0.29%, Nb: 0.011-0.034%, Ti: 0.011-0.019%, Al: 0.030-0.040%, with the remainder being Fe and unavoidable impurities.

[0181] More preferably, the chemical composition of the base material / base material layer is, by mass percentage, C: 0.08~0.12%, Si: 0.16~0.24%, Mn: 1.36~1.44%, P ≤ 0.015%, S ≤ 0.0025%, Cr: 0.11~0.19%, Ni: 0.06~0.14%, Nb: 0.016~0.024%, Ti: 0.011~0.019%, Al: 0.030~0.040%, with the remainder being Fe and unavoidable impurities.

[0182] More preferably, the chemical composition of the base material / base material layer is, by mass percentage, C: 0.05~0.09%, Si: 0.14~0.22%, Mn: 1.41~1.49%, P ≤ 0.012%, S ≤ 0.0020%, Cr: 0.16~0.24%, Ni: 0.11~0.19%, Mo: 0.11~0.19%, Nb: 0.021~0.029%, Ti: 0.011~0.019%, Al: 0.030~0.040%, with the remainder being Fe and unavoidable impurities.

[0183] As another preferred example, the chemical composition of the base material / base material layer is, by mass percentage, C: 0.03~0.07%, Si: 0.11~0.19%, Mn: 1.46~1.54%, P ≤ 0.010%, S ≤ 0.0015%, Cr: 0.21~0.29%, Ni: 0.16~0.24%, Cu: 0.16~0.24%, Mo: 0.16~0.24%, Nb: 0.026~0.034%, Ti: 0.011~0.019%, Al: 0.030~0.040%, with the remainder being Fe and unavoidable impurities.

[0184] The aforementioned stainless steel clad plate possesses excellent mechanical properties and corrosion resistance, and also has superior plate shape, interfacial bonding quality, uniformity, impact toughness, and surface quality compared to existing technologies.

[0185] Specifically, sampling was performed from a single-sided stainless steel clad plate of one embodiment of the present invention in accordance with GB / T 2975 - Steel and Steel Products - "Sampling Location and Specimen Preparation for Mechanical Performance Tests," and also, Regarding the plate shape, inspections were conducted in accordance with GB / T 709 - "Dimensions, shape, weight and tolerances of hot-rolled steel sheets and strips," and the flatness of the clad plate was ≤3 mm / m, and furthermore, flatness ≤2 mm / m. Regarding the interfacial bonding quality, tensile tests were performed on the clad plates in accordance with GB / T 6396 - "Methods for testing the mechanical and industrial performance of clad steel plates". The composite interfacial bonding rate of the clad plates was 100%, the shear strength was ≥300 MPa, and furthermore, the shear strength was ≥360 MPa. Regarding the mechanical performance, tensile tests were conducted in accordance with GB / T 6396 - "Methods for testing the mechanical and industrial performance of clad steel sheets" and GB / T 228.1 - "Tensile tests for metallic materials, Part 1: Room temperature test methods". The results showed that the clad sheet had a yield strength of ≥345 MPa, a tensile strength of ≥490 MPa, an elongation at break of ≥18%, a yield ratio of ≤0.85, a difference in Vickers hardness in the thickness direction of the base material layer of the clad sheet of ≤10, a strength difference between the front, middle, and rear sections of ≤40 MPa, and a strength difference between all parts of the entire sheet of ≤40 MPa. Tests were conducted in accordance with GB / T 6396 - "Methods for testing the mechanical and industrial performance of clad steel sheets" and GB / T 229 - "Charpy impact test method for metallic materials," and the clad sheets were found to have impact values ​​of ≥120J at 0°C, ≥120J at -20°C, ≥120J at -40°C, and furthermore, ≥240J at 0°C, ≥200J at -20°C, and ≥150J at -40°C. Sampling was performed in accordance with GB / T 2975 - Steel and Steel Products - "Sampling Location and Specimen Preparation for Mechanical Performance Tests," and testing was performed in accordance with GB / T 6396 - "Methods for Mechanical and Industrial Performance Tests of Clad Steel Plates." The clad plate showed no cracks at an external bend of 180° and no cracks at an internal bend of 180°.

[0186] Sampling was performed according to GB / T 6396 - "Methods for Testing the Mechanical and Industrial Performance of Clad Steel Sheets," and testing was performed according to GB / T 4334 - "Methods for Testing Intergranular Corrosion of Austenitic and Ferritic-Austenitic (Duplex) Stainless Steels for Corrosion of Metals and Alloys." After boiling the clad sheets in a sulfuric acid-copper sulfate solution for 20 hours and bending them 180°, no intergranular corrosion cracks were found in the clad layer.

[0187] In summary, compared to existing technologies, the present invention guarantees the corrosion resistance and mechanical strength of stainless steel clad plates through specific process control throughout the entire manufacturing method, preventing deterioration of corrosion resistance and mechanical performance during the clad material rolling process. On the other hand, it solves the problems of poor plate shape, poor interface bonding quality, and poor surface quality of existing stainless steel clad plates, providing stainless steel clad plates with superior plate shape and interface bonding quality, avoiding obvious surface defects such as dents and scratches caused by existing explosion bonding technology, and also solving the problems of dissimilar welding in existing technologies, thereby diversifying the types of clad plates, expanding their applications, and achieving high yield and production efficiency in the production process.

[0188] The above detailed description is merely a specific description of possible embodiments of the present invention and does not limit the scope of protection of the present invention. All equivalent embodiments or modifications that do not depart from the technical spirit of the present invention should be included within the scope of protection of the present invention.

[0189] The beneficial effects of the present invention will be further explained below with reference to several examples, but of course, these examples represent only a portion, not all, of the many variations included in the present invention.

[0190] The embodiments of the clad material manufacturing stage adopted in these examples are as described above, and refer to Tables 1 to 5 above. The specific chemical compositions of the steel types of clad materials and base materials in Tables 1 to 5 are shown in Table 6. Among these, "-" indicates elements that were not intentionally added during the steel manufacturing process (content is zero or nearly zero).

[0191] [Table 6]

[0192] Furthermore, each embodiment was carried out according to preferred embodiments of the heating, rolling, cooling, cutting, and planarization processes provided by the present invention, ultimately yielding single-sided stainless steel clad plate products. The total thickness, base material layer thickness, and clad material layer thickness of the clad plate products of these embodiments are shown in Table 7. In Table 7, where the two columns for clad plate thickness and base material layer thickness are in a range, they represent the minimum thickness to the maximum thickness.

[0193] Furthermore, sampling and testing were performed on the clad plates of each embodiment in accordance with the previously disclosed sampling criteria, test criteria, etc. The interfacial bonding rate for each embodiment was 100%, the inner bend to 180° passed (no cracks), and the outer bend to 180° passed (no cracks). In addition, even after boiling in a sulfuric acid-copper sulfate solution for 20 hours and then bending to 180°, there were no intergranular corrosion cracks in the clad material layer. The results of other performance tests are shown in Tables 7 and 8.

[0194] [Table 7]

[0195] Table 8

Claims

1. A method for manufacturing stainless steel clad steel plates for bridge structures, The process includes material preparation, release agent application, assembly, sealing, vacuuming, sealing, heating, rolling, cooling, cutting, and flattening. In the assembly process, the material is assembled using an upper carbon steel material A, a lower carbon steel material B, at least two stainless steel clad materials as an intermediate layer, and four sealing materials surrounding the four sides of the intermediate layer. Gas shield welding is performed between the sealing materials and material A, and between the sealing materials and material B to form a material assembly. Grooves are formed on each of the four sides of the material assembly, surrounded by material A, the sealing materials, and material B, respectively. Furthermore, a circular through-hole is provided in the sealing material on one side of the material assembly, and a steel pipe with an outer diameter r is welded to this through-hole. In the seal welding process, build-up welding is performed on the groove, leaving a cavity with radius R > r concentric with the steel pipe around the steel pipe during build-up welding, and when the penetration depth of the groove on the side where the steel pipe is positioned reaches 2 / 3 of the groove depth, and the penetration depth of the groove on the other side exceeds 2 / 3 of the groove depth, build-up welding is stopped. In the sealing process, after the vacuuming process of the material assembly is completed, the steel pipe is heated with a torch, flattened, and folded into the remaining cavity, and then the cavity is welded by gas shield welding to seal the steel pipe inside the cavity, and then build-up welding is continued until the groove is filled, and finally surface welding is performed to obtain the clad material assembly. In the rolling process, the clad material assembly coming out of the heating furnace is rolled to produce a large clad steel sheet. The first n passes of the entire rolling process are widthwise rolling, and from the (n+1)th pass onward, longitudinal rolling is employed. The reduction amount of the first pass is 25 mm or more, and the rolling temperature is 1060°C or higher. The width of the material after the nth pass is Wt + (0 to 40) mm, where Wt is the target width of the large clad steel sheet. The rolling temperature of the nth pass is 1030°C or higher. Between the nth pass and the (n+1)th pass, and between the (n+2)th pass and the (n+3)th pass, the material is water-cooled once in a reciprocating motion using six sets of headers, with a cooling water volume of 120 to 180 ml in the upper header of each set of headers. ３ / h, the cooling water volume in the lower header is 160-220 m³ ３ The rolling speed is 0.8 to 1.2 m / s, the reduction amount from the (n+1)th pass to the (n+3)th pass is 40 mm or more, the rolling temperature of the (n+1)th pass is 950°C or higher, in the mth pass, the rolling temperature is 900°C or higher, the material is rolled until the thickness is 2.5 to 3.5 times the target thickness of the clad steel sheet, then water cooling is performed to cool the material until the surface temperature is 840°C or lower, then the second stage of rolling is performed, the material is rolled until the thickness is the target thickness of the clad steel sheet, completing the entire rolling process, the rolling temperature of the first pass of the second stage rolling is 810°C to 840°C, and the rolling temperature of the final pass is 780 to 810°C. A method for manufacturing stainless steel clad steel plates for bridge structures.

2. In the seal welding process, when the penetration depth of the groove on the side where the steel pipe is positioned reaches 2 / 3 of the groove depth, and the penetration depth of the groove on the other side reaches the groove depth, the seal welding process is terminated. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

3. During build-up welding, multi-layer multi-pass welding is performed on the groove, starting with the upper and lower ends, followed by the middle section. Each layer undergoes at least four passes, with an interpass temperature of 140-160°C, a total of 6-8 welded layers, and an interlayer temperature of 150-250°C. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

4. In the assembly process, the through-hole is provided in the sealing material on one short side of the material assembly, and the through-hole is centered at a position that is 1 / 3 of the length and 1 / 2 of the width of the sealing material. The end face of the steel pipe is flush with the inner surface of the sealing material. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

5. In the assembly process, grooves are provided at the upper and lower ends of the outer surface of the sealing material, with a groove angle of 10 to 20° and a vertical depth of 10 to 15 mm. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

6. In the assembly process, the intermediate layer is arranged in layers and composed of clad material A and clad material B. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

7. In the material assembly obtained through the assembly process, material A and material B are both plates of equal thickness. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 6.

8. In the material assembly obtained by the assembly process, material A and material B are each unequal thickness plates whose thickness changes along the X direction, and the cladding joint surfaces of material A and material B are complementary to each other, and the X direction is the longitudinal direction or the width direction of material A and material B. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 6.

9. Material A and Material B are plates of varying thickness, with their thickness monotonically changing along the X direction, and their respective cladding surfaces are inclined planes, or Material A and Material B are plates of varying thickness, with their thickness varying non-monotonically along the X direction, and each cladding joint surface includes two or more planes arranged along the X direction. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 8.

10. In the assembly process, the intermediate layer is composed of two or more cladding materials arranged in parallel along the X direction, and the X direction is the longitudinal or widthwise direction of material A and material B. The joining sides of two adjacent clad materials are provided as parallel and complementary slanted edges, with one smaller surface in the thickness direction of each clad material forming the non-clad joint surface and the other larger surface forming the clad joint surface. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

11. In the heating process, the clad material assembly is heated in a heating furnace using a five-zone system: a preheating zone, a first heating zone, a second heating zone, a third heating zone, and a uniform heating zone. The preheating zone temperature is 850°C or lower, the first heating zone temperature is 1080±30°C, the second heating zone temperature is 1160±30°C, the third heating zone temperature is 1220±20°C, and the uniform heating zone temperature is 1190±20°C. The residence time in the third heating zone is (0.25 to 0.35) × t min / mm, where t is the thickness of the clad material assembly, and the residence time in the uniform heating zone is 15 min to 30 min. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

12. In the cooling process, the clad steel sheet obtained by rolling enters an ultra-rapid cooling system. The ultra-rapid cooling system has 24 sets of cooling headers arranged at 1m intervals along a roller table, with a cooling distance of 1m for each set of cooling headers. As the clad steel sheet passes through the ultra-rapid cooling system, the opening and closing states of all 24 sets of cooling headers are controlled by opening N sets of cooling headers and then closing M sets of cooling headers. The cooling water pressure is 0.15 to 0.30 MPa, the cooling rate is 3 to 15°C / s, and the final cooling temperature is 380 to 590°C, where N takes the value of 2, 3, or 4, and M takes the value of 2, 3, or 4. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

13. In the cooling process, a large clad steel plate, separated from the ultra-rapid cooling system, is placed on a cooling bed and cooled to room temperature by air cooling. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 12.

14. In the cooling process, when a large clad steel plate is removed from the ultra-rapid cooling system, the temperature reaches T ｆ -150℃ to T ｆ Lamination cooling was performed by placing the clad steel plate between two steel plates at +150°C, with a lamination cooling time of 0.4 min / mm × t0 ± 5 min, where t0 is the thickness of the clad steel plate. After the lamination cooling was completed, the clad steel plate was raised to a cooling bed and allowed to cool naturally to room temperature. Here, T ｆ = 550 + 30Si - 20Mn + 15Cr - 15Ni + 10Mo, where the element symbols in the formula represent 100 times the mass percentage of each element in material A and / or material B, and material A and material B have the same chemical composition. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 12.

15. When the thickness of the clad steel plate is 54 mm or less, the roller table speed of the ultra-rapid cooling system is 0.4 to 0.8 m / s, and the clad steel plate leaves the ultra-rapid cooling system after passing through it once. When the thickness of the clad steel plate is greater than 54 mm but less than 70 mm, the roller table speed of the ultra-rapid cooling system is 0.2 m / s or more and less than 0.6 m / s, and after the clad steel plate passes through the ultra-rapid cooling system once, it leaves the ultra-rapid cooling system, or When the thickness of the clad steel plate is 70 mm or more, the roller table speed of the ultra-rapid cooling system is 0.4 to 0.9 m / s, the clad steel plate first enters the ultra-rapid cooling system in the forward direction, and when its leading edge reaches the 24th cooling header, the roller table rotates in the reverse direction, causing the clad steel plate to pass through the ultra-rapid cooling system in the reverse direction and move away from the ultra-rapid cooling system inlet. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 12.

16. In the flat correction process, the clad material of the small one-sided clad steel plate obtained by the cutting process is placed upward on a flat correction machine for flat correction. When performing lateral flat correction, the correction force F1 of the flat correction machine is F1 = ν × a × b × c Ｔ × σ Ｔ / (d × (ν - c Ｔ / a)) is controlled. When performing longitudinal flat correction, the correction force F2 of the flat correction machine is F2 = a × b × c Ｖ × σ Ｖ / (d + c Ｖ ) is controlled. Here, a is the width (mm) of the small clad steel plate, b is the thickness (mm) of the small clad steel plate, c Ｔ is the unevenness per meter in the lateral direction of the small clad steel plate (mm), c Ｖ is the unevenness per meter in the longitudinal direction of the small clad steel plate (mm), d is the operating distance of the flat correction machine, σ Ｔ is the tensile yield strength in the lateral direction of the small clad steel plate, σ Ｖ is the tensile yield strength in the longitudinal direction of the small clad steel plate, and ν is the Poisson's ratio A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

17. Three vacuuming and two vacuum breaking procedures are performed on the internal space of the material assembly via the aforementioned steel pipe, and finally the vacuum level of the internal space of the material assembly is set to 10 －２ The process of maintaining the temperature below Pa is: First, the steel pipe is connected to a vacuum pump, and a vacuum is created in the internal space of the material assembly, with the vacuum level set to 10. －２ The pressure is set to Pa or below, and then maintained for at least 4 hours. Subsequently, the steel pipe is connected to a nitrogen supply device, a vacuum is broken on the material assembly, and nitrogen is filled in. Subsequently, the steel pipe is reconnected to the vacuum pump, and the material assembly is evacuated to a vacuum level of 10. －１ The pressure is set to Pa or less and not maintained, then the steel pipe is reconnected to the nitrogen supply device, a vacuum is broken on the material assembly, and nitrogen is filled in. Finally, as a third step, the steel pipe is connected to a vacuum pump, and the material assembly is evacuated to a vacuum level of 10. －２ Including setting it to Pa or less, A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

18. In the mold release agent application process, the mold release agent is applied to the non-clad joint surface of the clad material. The release agent used is a coating solution containing silicon dioxide and magnesium oxide, with a mass ratio of silicon dioxide to magnesium oxide of 3:1, or the components of the release agent used are, by mass ratio, 25-35% silicon nitride, 5-10% thermosetting amino resin, and 55-70% water. A method for manufacturing stainless steel clad steel plates for bridge structures according to claim 1.

19. A stainless steel clad steel sheet for bridge structures manufactured by the manufacturing method described in claim 1, wherein the chemical composition of the base material layer is, by mass percentage, C: 0.03 to 0.16%, Si: 0.11 to 0.29%, Mn: 1.31 to 1.54%, P: 0.018% or less, S: 0.0030% or less, Cr: 0.06 to 0.29%, Ni: 0.24% or less, Cu: 0.24% or less, Mo: 0.24% or less, Nb: 0.011 to 0.034%, Ti: 0.011 to 0.019%, Al: 0.030 to 0.040%, with the remainder being Fe and unavoidable impurities. The chemical composition of the cladding layer is, by mass percentage, C: 0.15% or less, Si: 1.00% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.030% or less, Ni: 6.0-22.0%, Cr: 16.0-26.0%, Mo: 3.0% or less, with the remainder being Fe and unavoidable impurities. The bonding ratio of the joint interface of the clad steel plate is 100%, and the shear strength is 300 MPa or more. Stainless steel clad steel plates for bridge structures.

20. The clad material layer covers only a portion of the upper surface of the base material layer, and does not cover the entire upper surface. Stainless steel clad sheet according to claim 19.

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