A method for manufacturing a composite board

Abstract

A method for manufacturing a composite plate includes the following steps: 1) cleaning the surface of the slab, cleaning the surface of the carbon steel plate and the stainless steel plate to be composited, wherein the brittle outer iron oxide layer is removed by shot blasting on the surface of the carbon steel plate, and only an inner iron oxide layer is retained, the thickness of which is less than or equal to 0.5 μm, and the surface unevenness after shot blasting is less than 0.2 mm; the iron oxide layer on the surface of the stainless steel plate is broken and completely cleaned; 2) assembling, a gap is maintained between the stainless steel plate and the carbon steel plate, and the gap size is controlled within 2 mm; edge welding is performed on the steel plate for assembling; 3) heating and rolling, and during the rolling process, the total compression ratio is greater than 6.0. The method of the present invention can meet the assembly process required for the composite plate under the condition of reducing the machining input and vacuum input as much as possible, achieve a balance between process efficiency and composite quality, and achieve an increase in assembly efficiency of 40%, and the composite quality reaches ultrasonic flaw detection level I.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite plate production, and particularly relates to a method for manufacturing a composite plate. Background Art

[0002] Currently, major domestic steel production enterprises are all carrying out the production of composite plates by rolling method. For example, the "method for manufacturing a composite slab for rolling a composite plate" disclosed in Chinese Patent No. CN201710305475.5. The technical solution is as follows: stack several slabs up and down, weld and seal the gaps around the slabs, leave a vacuum extraction steel pipe between the welds, perform vacuum treatment on the gap between the slabs through the vacuum extraction steel pipe, finally seal and weld the vacuum extraction steel pipe to make the gap between the slabs in a vacuum state, then heat in a heating furnace, and finally the rolling mill rolls the composite slab together to form. The present invention realizes the idea of achieving a vacuum state between the slabs under non-high-vacuum conditions, which is a breakthrough and progress in the existing process technology, greatly reducing the equipment investment for manufacturing composite slabs, and also simplifying the operation process, providing technical guarantee for expanding the production scale and increasing the product output, creating conditions for meeting the needs of the current rapid development of production, and having excellent popularization and application value in the industry.

[0003] For example, the "preparation method of a TMCP-type stainless steel composite plate for bridges" disclosed in Chinese Patent No. CN201610706997.1 prepares a stainless steel composite plate for bridges with good metallurgical bonding through steps such as blank selection, surface treatment, application of release agent, assembling of blanks, electron beam sealing welding, heating, rolling, straightening and cutting and splitting of plates. The invention uses electron beam direct sealing welding in a vacuum chamber environment, reducing processes such as drilling and vacuum extraction in the traditional process, and the vacuum degree is more guaranteed. Through the TMCP process, the good mechanical properties of the base material bridge steel are ensured, and the rapid cooling after rolling controls the intergranular precipitation of the clad material, ensuring the good corrosion resistance of the clad material; the base material uses a low-carbon designed blank, and for the prepared composite plate, the carbon equivalent of the base material is low, and the welding performance is good, facilitating on-site construction; in addition, the composite plate does not require heat treatment to obtain good comprehensive performance.

[0004] Chinese Patent No. CN201310169615.2 discloses a production process for composite plates, including the following steps implemented sequentially: surface machining of the bonding surface, end face machining, pressing, blank assembling, vacuum pumping and filling with inert gas, heating, hot rolling, and inspection. By adopting this production process for composite plates, the processing accuracy is improved, and the batch production of carbon steel-stainless steel composite plates with different specifications and thicknesses is realized; at the same time, by vacuum pumping and filling with inert gas, the air in the assembled blank is replaced, avoiding oxidation at the interface of the assembled blank during the subsequent heating process. Meanwhile, the extremely small amount of gas remaining between the composite interface and the two stainless steel interfaces will be gradually squeezed into the air storage bag as the rolling mill rolls and the assembled blank moves, avoiding the residual gas from displacing the separating agent or oxidizing the composite interface, effectively improving the bonding of the finished composite plate, and thus improving the quality of the composite plate.

[0005] Chinese Patent No. CN201510791439 discloses a production method for extra-thick stainless steel composite plates. Roll the Q235B billet into a nested plate with a thickness 3 - 10 mm greater than the thickness of two stainless steel plates; after rust removal, grinding, and air drying on the surface of the stainless steel plate, evenly spread a separating layer on the composite surface; then polish and grind each surface of the base blank; cut out a nested part corresponding to the size of the stainless steel plate from the nested plate and place it on the base blank, then stack two stainless steel plates in the nest, and cover another base blank on it; after the composite blank is put into the vacuum chamber for vacuum pumping, inspect the edges, spot weld, and finally continuously weld the base blank and the nest into one body; perform post-weld heat treatment and rolling, and cut off the steel plate of the nested part after rolling. The two stainless steel plates with the separating layer spread on them will naturally separate.

[0006] Chinese Patent No. CN201810530260.8 discloses a TMCP-type marine austenitic stainless steel composite plate and a preparation method thereof, including blank preparation, surface grinding, separating agent coating, blank assembling and sealing, electron beam seal welding, heating, rolling and cooling, straightening, and cutting and splitting the plate. The present invention effectively solves the problem of the corrosion resistance of the clad material austenitic stainless steel in the composite plate. At the same time, the processes such as drilling and vacuum pumping are reduced during the blank making process, the process is simple, and the rolling success rate is high.

[0007] Chinese Patent No. CN201711424997.3 discloses a preparation method for a TMCP-type marine duplex stainless steel composite plate. Through steps such as blank selection, surface treatment, separating agent coating, blank assembling, electron beam seal welding, heating, rolling, online quenching, straightening, and cutting and splitting the plate, a marine duplex stainless steel composite plate with good metallurgical bonding, excellent corrosion resistance, and structural strength is prepared.

[0008] As can be seen from the above patent, the key technology of the composite plate lies in the preliminary stock preparation, that is, the processing of the composite billet. Subsequently, the heating and rolling of the composite plate are completed on the existing rolling equipment. The preparation of the composite billet is mainly divided into three steps, namely, the surface cleaning of the slab, the welding of the four peripheral edges after assembling and laminating the billets, and the vacuum treatment at the bonding surface.

[0009] The surface cleaning of the slab is mainly to clean the scale on the slab surface, expose the fresh metal near the surface of the steel plate, and then the fresh metals on the surfaces of different metals can achieve mutual diffusion and penetration of metal elements during the hot rolling process to achieve the purpose of bonding.

[0010] After the slab is cleaned by surface machining, it needs to be subjected to vacuum treatment. The main purpose of vacuum treatment is to prevent the fresh metal exposed after machining from oxidizing in the air during the subsequent heating and rolling processes, generating a large amount of scale, which hinders the diffusion and penetration of elements of different metals and greatly hinders the purpose of metal bonding. Therefore, once the vacuum state between metals is achieved, it needs to be maintained until the heating, rolling, and cooling of the composite billet are completed. Once a vacuum leak occurs during this process, since the different metals have not yet been combined, oxygen in the air will continuously enter the bonding surface of the metals, producing oxides that hinder bonding. Therefore, the stability of the vacuum process is the key to the stable production of composite plates. Therefore, the welding process also has requirements for the airtightness of the weld quality.

[0011] According to different welding methods, it can be divided into two technical routes. The first technical route is vacuum electron beam welding, and the second technical route is to use a conventional welding method to fill welding metal + vacuum treatment. Vacuum electron beam welding is completed in a vacuum chamber. When the welding is completed, a vacuum cavity is also formed on the bonding surface after assembling and laminating the billets. For the conventional welding method, the welding is completed under non-vacuum conditions, and a separate vacuum extraction device needs to be used after welding to achieve the vacuum condition at the bonding surface after assembling and laminating the billets.

[0012] For the above two process routes, a large amount of man-hours and equipment investment are required for the surface cleaning of the slab, and a long time is also required to achieve the vacuum condition through special equipment. For the vacuum electron beam welding method, the electron beam can only be focused and welded in a vacuum environment, and the vacuum condition cannot be avoided. For the traditional welding method, the vacuum process requires separate man-hours and equipment. Therefore, there is an over-design phenomenon in the traditional composite billet process in terms of production process. Summary of the Invention

[0013] In view of the over-design existing in the traditional process, the purpose of the present invention is to provide a method for manufacturing a composite plate, which can meet the blank forming process requirements of the composite plate under the conditions of minimizing machining input and vacuum input as much as possible, and achieve both process efficiency and composite quality.

[0014] To achieve the above object, the technical solution of the present invention is as follows:

[0015] A method for manufacturing a composite plate, which comprises the following steps:

[0016] 1) Surface cleaning of the slab

[0017] Clean the surfaces of the carbon steel plate and the stainless steel plate to be compounded. Among them,

[0018] Remove the brittle outer oxide scale layer on the surface of the carbon steel plate by shot blasting, and only retain an inner oxide scale layer with a thickness less than or equal to 1 μm. The surface unevenness after shot blasting is less than 0.5 mm;

[0019] Completely remove the oxide scale on the surface of the stainless steel plate.

[0020] 2) Blank forming

[0021] Keep a gap between the stainless steel plate and the carbon steel plate, and control the gap size within 3 mm; perform edge welding on the steel plates to form a blank.

[0022] 3) Heating and rolling

[0023] The heating temperature is 1000 °C - 1200 °C. During the rolling process, the total reduction ratio is greater than 6.0.

[0024] Preferably, in step 1), the surface cleaning of the carbon steel is carried out by shot blasting twice. The first time, coarse shot is used for shot blasting, and the diameter of the shot is less than 1.5 mm. The second time, finer shot is used for shot blasting, and the diameter of the shot is less than 0.9 mm.

[0025] Preferably, in step 1), the stainless steel plate is polished by a sand belt to remove the oxide scale on its surface.

[0026] Preferably, during the rolling process in step 3), the total reduction ratio is greater than 10.0.

[0027] In the method of the present invention:

[0028] 1. Surface cleaning

[0029] The base plate is usually carbon steel, and its surface has a relatively thick oxide scale. Through scanning electron microscope analysis, the oxide scale layer is mainly composed of two parts, namely the outer oxide scale layer and the inner oxide scale layer, as Figure 1 shown.

[0030] The outer scale layer appears dark red, mainly composed of Fe2O3, and has great brittleness. Its thickness on the surface is unevenly distributed, the structure is relatively loose, it is not tightly combined with the inner scale layer, and it is easy to fall off under a certain external force (shot peening).

[0031] The inner scale layer appears black, mainly composed of FeO, and has great plasticity and high-temperature viscosity compared with the outer scale layer. Its thickness is relatively uniform, the structure is relatively dense, and it is tightly combined with the fresh metal inside the substrate. Usually, it needs to be removed by mechanical processing methods.

[0032] The scale residue on the slab surface strongly hinders the bonding between steel plates. Especially when the scale is continuously distributed over the entire surface, it is not conducive to the cladding of steel plates. Therefore, in the traditional billet assembly process, the first step is to clean the scale on the surface of the slabs to be bonded. Usually, for carbon steel, mechanical processing is used to clean the scale. This cleaning method is over-designed for the final cladding quality. For stainless steel, pickling process is used to treat the surface scale to completely clean the scale on the slab surface. Due to the environmental pollution caused by the pickling process, the environmental protection cost is very high.

[0033] The present invention proposes to appropriately control the scale residue, that is, on the surface of carbon steel, shot peening is used to remove the brittle outer scale layer and control the residue of the plastic inner scale layer. Combining with subsequent heating and rolling processes, that is, the heating temperature is 1000°C to 1200°C, and through a large total reduction ratio (the total reduction ratio is greater than 6.0), these remaining scale are broken into extremely small particles and presented in a dispersed distribution state. The fresh metal inside breaks through the obstruction of these scale, and through the thermal diffusion of metal elements, they are fully combined, thereby obtaining a composite plate with good bonding performance.

[0034] Preferably, the method of two-stage shot peening is adopted. In the first stage, large-sized shot is used for shot peening, and in the second stage, finer shot is used for shot peening to remove the brittle outer scale layer and control the residue of the plastic inner scale layer. After shot peening, there is no dark red and loose scale (mainly Fe2O3) on the surface, only a layer of black plastic inner scale (mainly FeO) remains, with a thickness less than 1μm, but still presented in a continuous distribution state in the length and width directions, and the surface unevenness after shot peening is less than 0.5mm.

[0035] The clad plate is usually stainless steel, and the scale on its surface is similar to that of ceramics in performance. The pickling process of the traditional process causes great pollution to the environment, and the investment in environmental protection cost is relatively high. The present invention uses (sand belt) grinding method to crush and clean the scale on the surface of stainless steel. After cleaning the surface, compressed air is used for purging, and it is checked that the surface completely presents a metallic bright color without black scale residue.

[0036] 2. Blank assembling

[0037] In the traditional process of blank assembling, certain equipment and man-hours are invested to conduct vacuum treatment on the interface between two steel plates, minimizing the residual air on the composite surface. Moreover, in the traditional vacuum composite blank assembling process, the vacuum process takes a long time.

[0038] As is well known, there is no absolute vacuum. The residual air within a certain range hinders the bonding of steel plates, but a small amount of residual air hardly hinders the bonding of steel plates. During the blank assembling process, due to the plate shape of the steel plates, there are gaps of varying sizes between the two blank surfaces, thus retaining a part of the air between the gap surfaces.

[0039] The present invention changes the traditional idea and instead adopts a method of controlling the plate shape, that is, using mechanical pressure to bring the two billets as close as possible, thereby further reducing the space between the two steel plates and controlling the amount of residual air on the composite surface to replace the control of air residue on the composite surface through the vacuum process in the traditional process. Similarly, during the subsequent welding process, the airtightness of the weld seam should be ensured, so that during the subsequent production process, the airtightness will not be damaged due to weld quality problems. Under the condition of ensuring airtightness, the limited residual air on the blank bonding surface will not hinder the elemental diffusion bonding between the steel plates. Welding and blank assembling are carried out on the edges of the billets, and the airtightness of the weld seam is emphasized during the welding process. During the subsequent high-temperature heating and rolling process with a large reduction ratio, the limited residual air is absorbed by the steel plates themselves.

[0040] 3. Heating and rolling of composite billets

[0041] In the heating and rolling composite process of the present invention, the heating temperature is 1000°C - 1200°C, and a large total reduction ratio is adopted during the rolling process, that is, under the condition that the total reduction ratio is greater than 6.0, the steel plates are rolled to a thinner range. Under the condition that the total reduction ratio is greater than 6.0, the residual plastic scale on the steel plate surface is further broken into extremely fine particles and dispersed on the composite surface. The size of these particles is less than 1μm in the thickness direction of the steel plate, and in the length and width directions, they are broken from the initial continuous distribution state into a dispersed distribution state, with the size in the length and thickness directions less than 3μm, and the spacing ranging from several μm to hundreds of μm. The fresh metal inside breaks through the obstruction of these scale, and the metal elements are fully bonded through thermal diffusion, thus realizing the bonding of the composite surface, and the composite quality reaches ultrasonic flaw detection grade I.

[0042] Advantages of the present invention:

[0043] Through the technical route of the present invention, the efficiency of the blank assembling process can be improved, that is, a large amount of machining time and vacuum extraction time are saved, the blank assembling efficiency is increased by 40% compared with the traditional process, and the composite quality of the product reaches ultrasonic flaw detection grade I. Description of the Drawings

[0044] Figure 1 It is a schematic diagram of the mill scale on the slab surface;

[0045] Figure 2 It is a metallographic photograph of the bonding surface of the composite plate in Embodiment 1 of the present invention;

[0046] Figure 3 It is a metallographic photograph of the bonding surface of the composite plate in Embodiment 2 of the present invention;

[0047] Figure 4 It is a SEM photograph of the bonding surface of the composite plate in Embodiment 2 of the present invention;

[0048] Figure 5 It is a metallographic photograph of the bonding surface of the composite plate in Embodiment 3 of the present invention. Detailed Description of the Invention

[0049] The present invention will be further described below in conjunction with the embodiments and the drawings.

[0050] The method for manufacturing the composite plate according to the present invention includes the following steps:

[0051] 1) Cleaning the surface of the slab

[0052] Clean the surfaces of the carbon steel plate and the stainless steel plate to be compounded. Among them,

[0053] Remove the brittle outer mill scale layer on the carbon steel plate surface by shot peening, and only retain a layer of black dense and plastic inner mill scale layer with a thickness less than or equal to 1 μm, which is continuously distributed in the length and width directions, and the surface roughness after shot peening is less than 0.5 mm;

[0054] Completely remove the mill scale on the stainless steel plate surface;

[0055] 2) Assembling the billets

[0056] Keep a gap between the stainless steel plate and the carbon steel plate, and control the gap size within 3 mm; perform edge welding on the steel plates to assemble the billets;

[0057] 3) Heating and rolling

[0058] The heating temperature is 1000 - 1200 °C, and during the rolling process, the total reduction ratio is greater than 6.0.

[0059] Preferably, in step 1), the surface cleaning of the carbon steel is carried out by shot peening twice. The first time, coarse shot peening is used with shot diameter less than 1.5 mm, and the second time, finer shot peening is used with shot diameter less than 0.9 mm to remove the brittle mill scale layer and control the remaining plastic mill scale.

[0060] Preferably, in step 1), the stainless steel plate is polished by a sand belt to break and clean the scale on its surface.

[0061] Preferably, during the rolling process in step 3), the total reduction ratio is controlled to be greater than 10.0.

[0062] Example 1

[0063] Under industrial experimental conditions, a composite plate is produced using a 100 - mm - thick Q235 carbon steel plate and a 20 - mm - thick 304 stainless steel plate. The steps are as follows:

[0064] 1) Preparation of composite slab blank

[0065] Carbon steel Q235, with a thickness of 90 mm, a width of 1300 mm, and a length of 2000 mm;

[0066] Stainless steel plate 304, with a thickness of 30 mm, a width of 1300 mm, and a length of 2000 mm;

[0067] 2) Surface cleaning of slab

[0068] The surfaces of the carbon steel plate and the stainless steel plate to be compounded are cleaned. Among them,

[0069] The brittle scale layer on the surface of the carbon steel plate is removed by shot blasting, and only an inner scale layer with a thickness less than or equal to 1 μm is retained. The surface unevenness after shot blasting is less than 0.2 mm;

[0070] The scale on the surface of the stainless steel plate is completely broken and cleaned;

[0071] 3) Assembling the slab

[0072] A gap is maintained between the stainless steel plate and the carbon steel plate, and the gap size is controlled within 2 mm. Edge welding is performed on the steel plates to assemble the slab, forming a 120 - mm - thick composite slab;

[0073] 4) Heavy plate rolling

[0074] The composite slab is heated to a temperature of 1150 °C and rolled on a heavy and wide plate rolling mill to 12 mm to obtain a composite plate;

[0075] The total reduction ratio of the above rolling process is 10.

[0076] The composite plate is qualified at ultrasonic flaw detection level I.

[0077] See Figure 2 , after analyzing the situation at the bonding surface of the steel plate through the above - mentioned process simulation, it can be seen that the residual plastic inner - layer scale on the interface has been completely broken under the condition of a large reduction ratio, and the fresh metals inside the original metals have fully diffused and combined into a whole.

[0078] Example 2

[0079] Under industrial production conditions, a large-scale production test of the composite process was carried out using a Q235 carbon steel plate and a 304 stainless steel plate. The steps are as follows:

[0080] 1) Preparation of composite slab billet

[0081] Carbon steel plate Q235, with a thickness of 159 mm, a width of 1350 mm, and a length of 5640 mm;

[0082] Stainless steel plate 304, with a thickness of 31 mm, a width of 1350 mm, and a length of 5640 mm;

[0083] 2) Surface cleaning of slab billet

[0084] The surfaces of the carbon steel plate and the stainless steel plate to be compounded were cleaned. Among them,

[0085] The brittle outer scale layer on the surface of the carbon steel plate was removed by shot blasting, and only an inner scale layer with a thickness less than or equal to 1 μm was retained. The surface unevenness after shot blasting was less than 0.2 mm;

[0086] The scale on the surface of the stainless steel plate was completely removed by breaking;

[0087] 3) Assembling of billets

[0088] A gap was maintained between the stainless steel plate and the carbon steel plate, and the size of the gap was controlled within 2.5 mm. Edge welding was carried out on the steel plates to assemble the billets, forming a composite billet with a thickness of 190 mm;

[0089] 4) Blooming rolling of thick plate

[0090] The composite billet was heated to a temperature of 1200 °C and rolled in the first stage on a heavy plate rolling mill to a thickness of 165 mm;

[0091] 5) Hot rolling into coils

[0092] After passing the ultrasonic flaw detection of Grade I, the billet entered the hot rolling production line, was heated to a temperature of 1100 °C, and rolled from a thickness of 165 mm to 3 mm into coils;

[0093] The total reduction ratio of the above two-stage rolling was 66.

[0094] See Figure 3 , which shows the metallography of the bonding interface of the clad layer of the steel plate sample. Under the technical conditions of the present invention, the scale on the surface of the original slab billet could not be observed in the metallographic photograph after being broken under the condition of a large reduction ratio.

[0095] Further observation was carried out by scanning electron microscopy, as shown in Figure 4As shown, inclusions formed by broken mill scale near the bonding surface of the composite plate can be observed. Their size is less than 1 μm, and sufficient diffusion bonding has occurred between the metals.

[0096] Example 3

[0097] Under industrial production conditions, a large-scale production test was carried out using a Q235 carbon steel plate and a 304 stainless steel plate. The steps are as follows:

[0098] 1) Preparation of composite slab billet

[0099] Carbon steel Q235, with a thickness of 300 mm, a width of 1600 mm, and a length of 4600 mm;

[0100] Stainless steel plate 304, with a thickness of 60 mm, a width of 1600 mm, and a length of 4600 mm;

[0101] 2) Surface cleaning of slab billet

[0102] The surfaces of the carbon steel plate and the stainless steel plate to be compounded were cleaned. Among them,

[0103] The brittle outer mill scale layer on the surface of the carbon steel plate was removed by shot blasting, and only an inner mill scale layer with a thickness less than or equal to 1 μm was retained. The surface roughness after shot blasting was less than 0.2 mm;

[0104] The mill scale on the surface of the stainless steel plate was completely removed by breaking it;

[0105] 3) Billet assembling

[0106] A gap was maintained between the stainless steel plate and the carbon steel plate, and the size of the gap was controlled within 3 mm. Edge welding was carried out on the steel plates to assemble the billet, forming a composite billet with a thickness of 360 mm;

[0107] 4) Blooming rolling of thick plate

[0108] The composite billet was heated to a temperature of 1150 °C and subjected to the first-stage rolling on a heavy plate rolling mill until it reached 180 mm;

[0109] 5) Hot rolling into coils

[0110] After passing the ultrasonic flaw detection at Grade I, the billet entered the hot rolling production line, was heated to a temperature of 1100 °C, and rolled from 180 mm to 3 mm into coils;

[0111] The total compression ratio of the above two-stage rolling was 120.

[0112] See Figure 5, Through the above process, analyzing the situation at the bonding surface of the composite plate, it can be seen that the residual plastic inner layer scale on the interface has been completely broken into dot-shaped inclusions under the condition of a large compression ratio, and the fresh metals inside the original metals have fully diffused and bonded into a whole.

[0113] Example 4

[0114] Under industrial production conditions, a large-scale production test was carried out using a Q345 carbon steel plate and a 30Cr13 stainless steel plate. The steps are as follows:

[0115] 1) Preparation of composite slab billets

[0116] Carbon steel Q235, with a thickness of 120 mm, a width of 1300 mm, and a length of 3000 mm;

[0117] Stainless steel plate 30Cr13, with a thickness of 90 mm, a width of 1300 mm, and a length of 3000 mm;

[0118] 2) Surface cleaning of slab billets

[0119] The surfaces of the carbon steel plate and the stainless steel plate to be compounded were cleaned. Among them,

[0120] The brittle outer scale layer on the surface of the carbon steel plate was removed by shot blasting, and only an inner scale layer with a thickness less than or equal to 1 μm was retained. The surface unevenness after shot blasting was less than 0.2 mm;

[0121] The scale on the surface of the stainless steel plate was completely removed by breaking it;

[0122] 3) Billet assembly

[0123] A gap was maintained between the stainless steel plate and the carbon steel plate, and the size of the gap was controlled within 2.6 mm. Edge welding was carried out on the steel plates to assemble the billets, forming a composite billet with a thickness of 210 mm;

[0124] 4) Heavy plate rolling

[0125] The composite billet was heated to a temperature of 1150 °C and rolled on a heavy and wide plate rolling mill until it reached 14 mm to obtain a composite plate;

[0126] The total compression ratio of the above rolling process was 15;

[0127] The above composite plate passed the ultrasonic flaw detection at Grade I.

[0128] Example 5

[0129] Under industrial production conditions, a large-scale production test was carried out using a Q345 carbon steel plate and a 30Cr13 stainless steel plate. The steps are as follows:

[0130] 1) Preparation of composite slab billets

[0131] Carbon steel Q235, thickness 120 mm, width 1300 mm, length 3000 mm;

[0132] Stainless steel plate 30Cr13, thickness 90 mm, width 1300 mm, length 3000 mm;

[0133] 2) Slab surface cleaning

[0134] Regarding the surface cleaning of the composite carbon steel plate and stainless steel plate, among which,

[0135] Use shot blasting on the surface of the carbon steel plate to remove the brittle outer scale layer, only leaving an inner scale layer with a thickness less than or equal to 1 μm, and the surface unevenness after shot blasting is less than 0.2 mm;

[0136] Completely clean the scale on the surface of the stainless steel plate;

[0137] 3) Blank assembling

[0138] Keep a gap between the stainless steel plate and the carbon steel plate, and control the gap size within 2.8 mm. Carry out edge welding and blank assembling on the steel plates to form a composite blank with a thickness of 210 mm;

[0139] 4) Heavy plate rolling

[0140] Heat the composite blank at a heating temperature of 1150 °C and roll it on a wide and heavy plate rolling mill until it reaches 35 mm to obtain a composite plate;

[0141] The total compression ratio of the above rolling process is 6;

[0142] The composite plate is qualified at level I through ultrasonic flaw detection.

Claims

1. A method for manufacturing a composite board, characterized in that, It includes the following steps: 1) Surface cleaning of slab Clean the surfaces of the carbon steel plate and the stainless steel plate to be compounded. Among them, Remove the brittle outer scale layer on the surface of the carbon steel plate by shot blasting, and only retain an inner scale layer with a thickness less than or equal to 1μm. The surface unevenness after shot blasting is less than 0.5mm; Completely remove the scale on the surface of the stainless steel plate; 2) Assembling the slabs Keep a gap between the stainless steel plate and the carbon steel plate, and control the gap size within 3mm; Perform edge welding and assembling on the steel plates; 3) Heating and rolling The heating temperature is 1000°C - 1200°C. During the rolling process, the total reduction ratio is greater than 6.

0.

2. The composite board manufacturing method according to claim 1, characterized in that, In step 1), the surface cleaning of the carbon steel is carried out by shot blasting twice. The first time, coarse shot is used for shot blasting, and the diameter of the shot is less than 1.5mm. The second time, finer shot is used for shot blasting, and the diameter of the shot is less than 0.9mm.

3. The method for manufacturing a composite board according to claim 1 or 2, characterized in that, In step 1), the stainless steel plate is polished with a sand belt to remove the scale on its surface.

4. The method for manufacturing a composite board according to claim 1 or 2, characterized in that, During the rolling process in step 3), the total reduction ratio is greater than 10.

0.

5. The composite board manufacturing method according to claim 3, wherein During the rolling process in step 3), the total reduction ratio is greater than 10.0.

Images