Method of manufacturing a multi-layer stainless steel clad slab

Abstract

The application discloses a kind of methods for manufacturing multilayer stainless steel composite slab, it relates to stainless steel composite slab production technical field, comprising: determine the stainless steel plate for manufacturing composite slab, select the two stainless steel plates of optimal corrosion resistance, mechanical property and welding performance as outermost stainless steel plate;Respectively on two outermost stainless steel plate mechanical processing rectangular groove;Its remaining stainless steel plate is stacked into rectangular groove, and the stacked stainless steel plate is encapsulated using two outermost stainless steel plate to form group slab;After positioning welding to two outermost stainless steel plate, group slab is placed into vacuum chamber, and vacuum degree is extracted;Group slab is welded in vacuum chamber using electron beam;Group slab after electron beam welding is stress relieving heat treatment, and composite slab is obtained.The method for manufacturing multilayer stainless steel composite slab of the application can reduce the number of welds, improve the success rate of slab making, and can efficiently and quickly manufacture small-specification multilayer stainless steel composite slab.

Description

Technical Field

[0001] This invention relates to the field of stainless steel composite slab production technology, and in particular to a method for manufacturing multi-layer stainless steel composite slabs. Background Technology

[0002] Stainless steel refers to iron-based alloys with a chromium content of 11-30% and the addition of various other alloying elements. There are many grades of stainless steel, but based on their microstructure, they can be divided into ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, duplex stainless steel, and precipitation-hardening stainless steel. Each type of stainless steel has similar weldability; except for a few martensitic stainless steels, similar or dissimilar stainless steels can be welded together. As an important corrosion-resistant structural material, stainless steel is currently widely used in energy, chemical, and medical fields. To meet the comprehensive performance requirements of materials under specific working conditions, it is often necessary to composite different types of stainless steel in the thickness direction, and then achieve atomic-level bonding of dissimilar metals through rolling. The manufacturing quality of such composite slabs directly determines the interfacial bonding strength and service performance of the final composite plate.

[0003] There are two main methods for manufacturing traditional stainless steel composite slabs: hot rolling composite method and conventional welding edge sealing method. The hot rolling composite method requires large rolling mills and high temperature and high pressure environment, resulting in large equipment investment, high energy consumption, and poor adaptability to small batches and multiple specifications. The conventional welding edge sealing method uses arc welding (such as tungsten inert gas welding TIG and gas metal arc welding MIG) to seal and fix the edges of the laminated steel plates, but it has the following defects in actual use: shallow penetration and low depth-to-width ratio, making it difficult to achieve complete fusion of the thick plate interface and easily producing incomplete penetration defects; wide heat-affected zone, high heat input leads to sensitization and deformation of stainless steel, especially for martensitic steel, which is prone to cracking; poor compatibility with dissimilar metals, and stainless steels with large differences in composition and thermophysical properties are prone to forming brittle phases when welded. Summary of the Invention

[0004] To address some or all of the technical problems existing in the prior art, the present invention provides a method for manufacturing multilayer stainless steel composite slabs.

[0005] The technical solution of the present invention is as follows:

[0006] A method for manufacturing a multilayer stainless steel composite slab is provided, comprising:

[0007] The stainless steel plates used to manufacture the composite slab were determined, and the two stainless steel plates with the best corrosion resistance, mechanical properties and weldability were selected as the outermost stainless steel plates.

[0008] Rectangular grooves were machined onto the two outermost stainless steel plates respectively.

[0009] The remaining stainless steel plates are stacked in a rectangular groove, and the stacked stainless steel plates are encapsulated by two outermost stainless steel plates to form a preform. The total thickness of the stacked remaining stainless steel plates is not less than 95% of the internal height of the box structure formed after the two outermost stainless steel plates are encapsulated.

[0010] After tack welding the two outermost stainless steel plates, the assembly is placed in a vacuum chamber, and the vacuum chamber is evacuated to a vacuum level of 10. -4 ~10 -1 Torr;

[0011] Electron beam welding was performed on the preform in a vacuum chamber. The electron beam accelerating voltage was 70–80 kV, the electron beam current was 150–200 mA, and the welding speed was 150–180 mm / min.

[0012] The composite slab was obtained by stress-relieving heat treatment at a temperature of 650±10℃ for 2 to 3 hours after electron beam welding.

[0013] In some alternative implementations, the method further includes cleaning the surface of the stainless steel before stacking the stainless steel sheet in the rectangular groove.

[0014] In some alternative embodiments, the method further includes: tack welding the two outermost stainless steel plates using tungsten inert gas welding.

[0015] In some optional embodiments, when performing electron beam welding on the preform, a horizontal welding method is adopted, and the welding is completed in two passes. The electron beam accelerating voltage of the first pass is 70-80kV, the electron beam current is 150-200mA, and the welding speed is 150-180mm / min. The electron beam accelerating voltage of the second pass is 70-80kV, the electron beam current is 50-60mA, and the welding speed is 150-180mm / min.

[0016] In some alternative implementations, the outermost stainless steel plate has one or more rectangular slots, with the remaining stainless steel plates stacked on each rectangular slot.

[0017] In some alternative embodiments, the type of stainless steel sheet includes one or more of the following: ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, duplex stainless steel, and precipitation hardening stainless steel.

[0018] In some alternative embodiments, the stainless steel plate has a length of 399–999 mm, a width of 199–399 mm, and a thickness of ≤99 mm.

[0019] In some optional embodiments, the composite slab has a length ≤999mm, a width ≤399mm, a thickness ≤399mm, and a composite layer count of 3 to 99 layers.

[0020] The main advantages of the technical solution of this invention are as follows:

[0021] The method for manufacturing multi-layer stainless steel composite slabs of the present invention determines the stacking order of each layer of stainless steel plates based on the physical and microstructure characteristics of the stainless steel plates used to manufacture the composite slab. By processing rectangular grooves on the two outermost stainless steel plates, stacking the middle layer of stainless steel plates in the rectangular grooves to form a box structure, and using electron beam welding with set welding parameters to weld the stainless steel plates, the number of welds can be reduced, the success rate of slab preparation can be improved, and small-sized multi-layer stainless steel composite slabs can be manufactured efficiently and quickly, ensuring that the microstructure and specifications of the obtained composite slab meet the application requirements. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0023] Figure 1 A flowchart of a method for manufacturing a multilayer stainless steel composite slab provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the main structure of a stainless steel composite slab provided in an embodiment of the present invention;

[0025] Figure 3 for Figure 2 A schematic diagram of the AA-direction cross-section structure;

[0026] Figure 4 for Figure 2 Schematic diagram of the BB-direction cross-section structure. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] The technical solutions provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] refer to Figure 1-4 This invention provides a method for manufacturing multilayer stainless steel composite slabs, the method comprising the following steps:

[0030] Step 1: Determine the stainless steel plates to be used to manufacture the composite slab, and select the two stainless steel plates with the best corrosion resistance, mechanical properties and weldability as the outermost stainless steel plates.

[0031] Step 2: Machining rectangular grooves on the two outermost stainless steel plates respectively;

[0032] Step 3: Stack the remaining stainless steel plates into the rectangular groove, and use the two outermost stainless steel plates to encapsulate the stacked stainless steel plates to form a preform. The total thickness of the stacked remaining stainless steel plates shall not be less than 95% of the internal height of the box structure formed after the two outermost stainless steel plates are encapsulated.

[0033] Step 4: After tack welding the two outermost stainless steel plates, place the assembly into the vacuum chamber and evacuate the chamber to a vacuum level of 10. -4 ~10 -1 Torr;

[0034] Step 5: Electron beam welding is performed on the preform in a vacuum chamber. The electron beam accelerating voltage is 70-80kV, the electron beam current is 150-200mA, and the welding speed is 150-180mm / min.

[0035] Step 6: Perform stress-relief heat treatment on the electron beam welded billet at a temperature of 650±10℃ for 2 to 3 hours to obtain the composite slab billet.

[0036] In this embodiment of the invention, the size of the stainless steel stacked in the rectangular groove is slightly smaller than the size of the rectangular groove.

[0037] Electron beam welding technology uses a high-energy electron beam as a heat source. The high-energy-density electron beam bombards the metal at the joint of the workpiece, causing it to melt rapidly. This melted metal is then quickly cooled and solidified to achieve the welding purpose. Electron beam welding is widely used in aerospace, nuclear energy and military, automotive, and electrical instrumentation industries due to its advantages such as no need for welding rods, minimal oxidation, good process repeatability, and small thermal deformation. The basic principle of electron beam welding is that the cathode in the electron gun emits electrons due to direct or indirect heating. These electrons are accelerated by a high-voltage electrostatic field and then focused by an electromagnetic field to form an electron beam with extremely high energy density. This electron beam bombards the workpiece, converting its enormous kinetic energy into heat energy, melting the workpiece at the welding point and forming a molten pool, thus achieving welding. Electron beam welding has the following characteristics: it has high energy density, enabling the welding of seams that are difficult to achieve with conventional arc welding; it is performed in a vacuum, resulting in a stable and pure chemical composition of the weld, high joint strength, and high weld quality; it is fast, with a small heat-affected zone and minimal thermal deformation; it is suitable for welding almost all metallic materials, especially dissimilar metals; it can produce welds with a large depth-to-width ratio (20:1 to 50:1), allowing for one-time forming of thick parts without beveling; and combined with computer technology, it enables precise control of process parameters, making the welding process fully automated.

[0038] The method for manufacturing multi-layer stainless steel composite slabs provided in this invention determines the stacking order of each layer of stainless steel plates based on the physical and microstructure characteristics of the stainless steel plates used to manufacture the composite slabs. By processing rectangular grooves on the two outermost stainless steel plates, and stacking the middle layer of stainless steel plates in the rectangular grooves to form a box structure, the stainless steel plates are welded using electron beam welding with set welding parameters. This method can reduce the number of welds, improve the success rate of slab preparation, and efficiently and quickly manufacture small-sized multi-layer stainless steel composite slabs, ensuring that the resulting composite slabs meet the requirements for use in terms of microstructure and specifications.

[0039] Furthermore, in this embodiment of the invention, the method further includes: cleaning the surface of the stainless steel before stacking the stainless steel plate in the rectangular groove.

[0040] In this embodiment of the invention, by cleaning the surface of stainless steel, oil stains and oxide films on the surface of stainless steel plates can be removed, avoiding defects such as porosity and lack of fusion in electron beam welding, improving welding quality, and increasing the interface bonding rate after rolling.

[0041] Furthermore, in this embodiment of the invention, the method further includes: using tungsten inert gas welding to perform tack welding on the two outermost stainless steel plates.

[0042] In this embodiment of the invention, by using tungsten inert gas welding for tack welding, the heat-affected zone of the weld can be controlled to be less than 2mm, preventing deformation of the tack welding from interfering with the accuracy of the electron beam weld.

[0043] Furthermore, in this embodiment of the invention, when performing electron beam welding on the preform, a horizontal welding method is adopted, and the welding is completed in two passes. The electron beam accelerating voltage for the first pass is 70-80kV, the electron beam current is 150-200mA, and the welding speed is 150-180mm / min. The electron beam accelerating voltage for the second pass is 70-80kV, the electron beam current is 50-60mA, and the welding speed is 150-180mm / min.

[0044] In this embodiment of the invention, when performing electron beam welding, a horizontal welding method is adopted and the welding is completed in two passes. The second pass is a finishing weld, which can precisely control the penetration depth and improve the welding quality.

[0045] Furthermore, in this embodiment of the invention, the rectangular groove on the outermost stainless steel plate includes one or more, and the remaining stainless steel plates are stacked on each rectangular groove.

[0046] In this embodiment of the invention, by setting one or more rectangular grooves, each of which independently stacks the stainless steel plate of the middle layer, the actual needs for preparing different composite slabs can be met.

[0047] Furthermore, in this embodiment of the invention, the type of stainless steel plate includes one or more of the following: ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, duplex stainless steel, and precipitation hardening stainless steel.

[0048] The method for manufacturing multilayer stainless steel composite slabs provided in this invention can realize the preparation of various types of stainless steel composite slabs, including ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, duplex stainless steel and precipitation hardening stainless steel.

[0049] Furthermore, in this embodiment of the invention, the stainless steel plate has a length of 399-999 mm, a width of 199-399 mm, and a thickness of ≤99 mm; the composite slab has a length of ≤999 mm, a width of ≤399 mm, a thickness of ≤399 mm, and a composite layer count of 3-99 layers.

[0050] To make the above technical solutions of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0051] Example 1

[0052] In Example 1, a multi-layer stainless steel composite slab of 304-0Cr13-304-440C-304-0Cr13-304 was prepared.

[0053] 440C stainless steel is a high-strength, high-hardness martensitic stainless steel used to manufacture high-end knives and tools. However, due to its high carbon content, strength, and hardness, its production cost is high and its rolling process is difficult. To solve these problems, a multi-layer stainless steel composite slab was designed. The outermost layer is made of ordinary 304 stainless steel, the middle layer is 440C stainless steel, and the outermost and middle layers are 0Cr13 ferritic stainless steel and 304 stainless steel. The resulting composite slab ensures both the corrosion resistance of the materials and the sharpness and hardness of the blade, making it an ideal composite material for making knives.

[0054] In Example 1, when preparing the 304-0Cr13-304-440C-304-0Cr13-304 multilayer stainless steel composite slab, a size of 150×400×500mm was selected. 3 Thick 304 stainless steel plates were used as the outer layer material, one piece on the top and one on the bottom, and were machined to have a volume of 110×310×410mm. 3 The rectangular groove is then filled with intermediate layer stainless steel plates of the corresponding size, which are stacked sequentially. The total thickness of the intermediate layer is approximately 210mm. Before stacking and assembling, the surfaces of each stainless steel plate are cleaned. After the stacking is completed, the two outer 304 stainless steel thick plates are tack welded using tungsten inert gas welding to initially fix the assembly and ensure the smooth progress of electron beam edge sealing welding. After the assembly is placed in the vacuum chamber, a vacuum is drawn until the vacuum degree reaches 10. - 3 The process involves heating the electron beam emitting wire with a heating current of 30A. The electron beam welding method is horizontal welding, performed in two passes. The first pass has an accelerating voltage of 75KV, an electron beam current of 160mA, and a welding speed of 180mm / min. The second pass is a finishing weld with an accelerating voltage of 75KV, an electron beam current of 50mA, and a welding speed of 180mm / min. After welding, the slab is removed and subjected to post-weld stress-relieving heat treatment at 650℃ for 2–3 hours to obtain the final composite slab.

[0055] Composite slabs were hot-rolled on a small hot rolling mill. The billet was held at 1200℃ for 8 hours. After several rolling passes, a hot-rolled plate with a thickness of 3mm was obtained. By observing the microstructure, it was found that the stainless steel between the layers of the hot-rolled plate had achieved atomic bonding, which met the technical requirements.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the terms "front," "back," "left," "right," "upper," and "lower" in this document refer to the placement shown in the accompanying drawings.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing multi-layer stainless steel composite slabs, characterized in that, include: The stainless steel plates used to manufacture the composite slab were determined, and the two stainless steel plates with the best corrosion resistance, mechanical properties and weldability were selected as the outermost stainless steel plates. Rectangular grooves were machined onto the two outermost stainless steel plates respectively. The remaining stainless steel plates are stacked in a rectangular groove, and the stacked stainless steel plates are encapsulated by two outermost stainless steel plates to form a preform. The total thickness of the remaining stacked stainless steel plates is not less than 95% of the internal height of the box structure formed after the two outermost stainless steel plates are encapsulated. After tack welding the two outermost stainless steel plates, the assembly is placed in a vacuum chamber, and the vacuum chamber is evacuated to a vacuum level of 10. -4 ~10 -1 Torr; Electron beam welding of the preform was performed in a vacuum chamber using a horizontal welding method, and was completed in two passes. The electron beam accelerating voltage for the first pass was 70~80kV, the electron beam current was 150~200mA, and the welding speed was 150~180mm / min. The electron beam accelerating voltage for the second pass was 70~80kV, the electron beam current was 50~60mA, and the welding speed was 150~180mm / min. The composite slab was obtained by stress-relieving heat treatment at a temperature of 650±10℃ for 2~3 hours after electron beam welding.

2. The method for manufacturing multi-layer stainless steel composite slabs according to claim 1, characterized in that, The method further includes cleaning the surface of the stainless steel before stacking the stainless steel plate in the rectangular groove.

3. The method for manufacturing multi-layer stainless steel composite slabs according to claim 1, characterized in that, The method also includes: using tungsten inert gas welding to perform tack welding on the two outermost stainless steel plates.

4. The method for manufacturing multi-layer stainless steel composite slabs according to claim 1, characterized in that, The outermost stainless steel plate has one or more rectangular slots, with the remaining stainless steel plates stacked on top of each rectangular slot.

5. The method for manufacturing multi-layer stainless steel composite slabs according to claim 1, characterized in that, Stainless steel plates include one or more of the following: ferritic stainless steel, austenitic stainless steel, martensitic stainless steel, duplex stainless steel, and precipitation hardening stainless steel.

6. The method for manufacturing multi-layer stainless steel composite slabs according to claim 1, characterized in that, The stainless steel sheet has a length of 399~999mm, a width of 199~399mm, and a thickness of ≤99mm.

7. The method for manufacturing multilayer stainless steel composite slabs according to claim 1, characterized in that, The length of the composite slab is ≤999mm, the width is ≤399mm, the thickness is ≤399mm, and the number of composite layers is 3~99 layers.

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