Preparation method of high-nitrogen stainless steel-carbon steel composite plate

Abstract

The invention provides a preparation method of a high-nitrogen stainless steel-carbon steel composite plate, which belongs to the technical field of metal composite plate preparation and comprises the following steps: S1, preparing a high-nitrogen stainless steel ingot and forging the high-nitrogen stainless steel ingot into a high-nitrogen stainless steel bar; s2, the high-nitrogen stainless steel bar is inserted into an inner hole of the rotatable stirring head, and the bottom face of the high-nitrogen stainless steel bar makes close contact with the surface of the base plate; s3, the high-nitrogen stainless steel bar is subjected to one-pass high-nitrogen stainless steel deposition on the surface of the base plate along a preset deposition track in the rotating and axially downward feeding state; and S4, preparing at least one high-nitrogen stainless steel deposition layer on the surface of the substrate. According to the preparation method, the composite layer is prepared through stirring friction, rolling thermal deformation and high-temperature plasticizing of the high-nitrogen stainless steel bar, surface forming of the deposition layer is flattened by controlling bar flow and material transfer rate, the problems of nitrogen escape and air holes in the preparation process of the composite layer can be effectively avoided, and the large-size high-nitrogen stainless steel-carbon steel composite plate is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of metal composite plate preparation, and more particularly, to a method for preparing a high-nitrogen stainless steel-carbon steel composite plate. Background Art

[0002] High-nitrogen stainless steel is considered to be one of the most promising new engineering materials due to its excellent corrosion resistance in various corrosive media, good comprehensive mechanical properties, and excellent processing properties. It has been widely used in many fields such as the bioenergy industry, aerospace, petrochemical industry, ocean engineering, and biomedicine. The definition of high-nitrogen steel is mainly related to the nitrogen content. For ferritic and martensitic stainless steels, when the nitrogen content is higher than 0.08% (mass fraction), it is classified as high-nitrogen steel; for austenitic stainless steels, when the nitrogen content in the austenite is higher than 0.40% (mass fraction), it is called high-nitrogen steel. Stainless steel-carbon steel composite plates combine the advantages of two metal materials, and at the same time can greatly reduce the use of rare and precious metals, reduce production costs, and have extremely high cost performance.

[0003] At present, the preparation of stainless steel-carbon steel composite plates mainly includes explosion method, hot rolling method, and explosion-hot rolling composite method, etc., and has been applied in many industrial fields. However, the above methods are only applicable to the preparation of composite plates with low nitrogen content, and when preparing composite plates with large size specifications, large-size stainless steel raw materials are also required.

[0004] However, due to the limitation of the production of large-size high-nitrogen stainless steel raw materials, the preparation of large-size high-nitrogen stainless steel-carbon steel composite plates has always been an industrial technical problem. The methods for preparing high-nitrogen stainless steel at home and abroad are: nitrogen pressure melting method, powder metallurgy method, and surface nitriding method; the nitrogen pressure melting method is the most commonly used method, and due to the limitation of special high-pressure metallurgical equipment and technology, there are still great limitations in the preparation of large-size steel ingots with uniform structure and composition; the powder metallurgy method mainly prepares bulk high-nitrogen stainless steel through hot pressing sintering and cladding of high-nitrogen alloy powders. Among them, the powder metallurgy method is limited by sintering equipment and cannot prepare large-size blank parts; the disadvantages of using laser, arc and other cladding methods are that the problems of nitrogen escape and porosity are prominent, and it is impossible to prepare a dense high-nitrogen stainless steel structure.

[0005] Therefore, it is necessary to provide a method for preparing a large-size high-nitrogen stainless steel-carbon steel composite plate that can obtain a high-nitrogen stainless steel structure with fine grains and dense structure. Summary of the Invention

[0006] In view of the problems of production restrictions of large-sized high-nitrogen stainless steel raw materials in the preparation of large-sized high-nitrogen stainless steel-carbon steel composite plates proposed above, and the technical problems of nitrogen escape and pores in the existing methods for preparing high-nitrogen stainless steel structures, which affect the nitrogen content and tissue density, a preparation method for large-sized high-nitrogen stainless steel-carbon steel composite plates capable of obtaining a high-nitrogen stainless steel structure with fine grains and dense tissue is provided.

[0007] The technical means adopted in the present invention are as follows: A preparation method for a high-nitrogen stainless steel-carbon steel composite plate, wherein the substrate of the high-nitrogen stainless steel-carbon steel composite plate is carbon steel, and the composite layer is high-nitrogen stainless steel. The composite layer is prepared from a high-nitrogen stainless steel ingot. The preparation method includes the following steps: S1. Prepare a high-nitrogen stainless steel ingot and forge it into a high-nitrogen stainless steel bar with a cross-sectional shape matching the inner hole shape of the stirring head; S2. Insert the high-nitrogen stainless steel bar into the inner hole of the rotatable stirring head, so that the bottom surface of the high-nitrogen stainless steel bar is in close contact with the surface of the substrate; S3. Under the state of rotation and axial downward feeding of the high-nitrogen stainless steel bar, perform a single-pass high-nitrogen stainless steel deposition on the surface of the substrate along a predetermined deposition track. During the deposition process: control the stirring head to drive the high-nitrogen stainless steel bar to rotate, and the rotation speed v 1 is 200-800 r / min; apply a load axially downward along the stirring head to push the high-nitrogen stainless steel bar to feed, and the feeding speed v 2 is 10-50 mm / min; when controlling the stirring head to drive the high-nitrogen stainless steel bar to move along a predetermined deposition track, the moving speed v 3 is 50-100 mm / min; S4. Prepare at least one layer of high-nitrogen stainless steel deposition layer on the surface of the substrate. Each layer of high-nitrogen stainless steel deposition layer is formed by performing multiple passes of high-nitrogen stainless steel deposition by repeating step S3.

[0008] Further, in terms of mass percentage, the chemical components contained in the high-nitrogen stainless steel ingot in step S1 are as follows: the manganese element content is 10-30%, the chromium element content is 10-25%, the molybdenum element content is 1-5%, the nickel element content ≤ 3%, the nitrogen element content ≥ 0.4%, and the rest is iron element.

[0009] Further, in step S3, before performing high-nitrogen stainless steel deposition, the distance between the bottom end face of the stirring head and the substrate is 1-3 mm.

[0010] Further, in step S3, control the high-nitrogen stainless steel bar to stay at the initial position of the predetermined deposition track for 5-10 s, and then move along the predetermined deposition track.

[0011] Further, in each layer of the high-nitrogen stainless steel deposition layer prepared in step S4, there is an overlap between adjacent passes.

[0012] Further, the overlap width is 3 - 5 mm.

[0013] Further, argon is used for protection during the deposition of high-nitrogen stainless steel.

[0014] Further, during the deposition of high-nitrogen stainless steel, online cooling is carried out by means of air cooling or water cooling.

[0015] Further, in step S1, the high-nitrogen stainless steel ingot is forged into the high-nitrogen stainless steel bar after solution treatment at 1100°C.

[0016] Further, the shape of the inner hole of the stirring head is square, and the cross-sectional shape of the high-nitrogen stainless steel bar in step S1 is square, which is matched with the shape of the inner hole of the stirring head.

[0017] Compared with the prior art, the present invention has the following advantages: 1. The preparation method of the high-nitrogen stainless steel-carbon steel composite plate provided by the present invention can flexibly adjust the process parameters according to the types and sizes of the required composite plates. Moreover, the raw material is a small-sized high-nitrogen stainless steel ingot that is easy to obtain, instead of a large-sized high-nitrogen stainless steel plate that is difficult to obtain, as well as explosive means or large rolling equipment. The production cost is low and the efficiency is high.

[0018] 2. The preparation method of the high-nitrogen stainless steel-carbon steel composite plate provided by the present invention plastifies the high-nitrogen stainless steel bar at high temperature through friction stir and rolling thermal deformation, and controls its flow and material transfer rate through the stirring head. Further, the surface of the deposition layer is formed flat, and an ultra-high nitrogen content stainless steel deposition layer with a nitrogen content higher than 0.40% that cannot be obtained by the existing melting method is prepared. Moreover, the entire deposition process is within the solid-state thermal deformation temperature range, and the tissue evolution is completed through the dynamic recrystallization mechanism, which can effectively avoid nitrogen escape and pore problems, making the obtained deposition layer have fine grains, dense tissue, and good comprehensive properties (strength and plasticity). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1Schematic diagram of the process for preparing the high-nitrogen stainless steel-carbon steel composite plate of the present invention.

[0021] Figure 2 Metallographic diagram of the cross-sectional structure of the high-nitrogen stainless steel-carbon steel composite plate in Example 1.

[0022] Figure 3 EBSD analysis diagram of the composite layer of the high-nitrogen stainless steel-carbon steel composite plate in Example 1.

[0023] Figure 4 Tensile curve of the composite layer of the high-nitrogen stainless steel-carbon steel composite plate in Example 1.

[0024] Figure 5 Metallographic diagram of the cross-sectional structure of the high-nitrogen stainless steel-carbon steel composite plate in Example 2.

[0025] Figure 6 EBSD analysis diagram of the composite layer of the high-nitrogen stainless steel-carbon steel composite plate in Example 2.

[0026] Figure 7 Tensile curve of the composite layer of the high-nitrogen stainless steel-carbon steel composite plate in Example 2.

[0027] In the figure: 1. High-nitrogen stainless steel bar; 2. Stirring head; 3. Hydraulic push rod; 4. Carbon steel; 5. First-layer high-nitrogen stainless steel deposition layer; 6. Second-layer high-nitrogen stainless steel deposition layer. Detailed implementation manners

[0028] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] As Figure 1 shown, the present invention provides a method for preparing a high-nitrogen stainless steel-carbon steel composite plate. The base plate of the high-nitrogen stainless steel-carbon steel composite plate is carbon steel, and the composite layer is high-nitrogen stainless steel. The composite layer is prepared from a high-nitrogen stainless steel ingot; The preparation method includes the following steps: S1. Prepare a high-nitrogen stainless steel ingot and forge it into a high-nitrogen stainless steel bar with a cross-sectional shape matching the inner hole shape of the stirring head; S2. Insert the high-nitrogen stainless steel bar into the inner hole of the rotatable stirring head, so that the bottom surface of the high-nitrogen stainless steel bar is in close contact with the surface of the substrate; S3. Under the state of rotation and axial downward feeding of the high-nitrogen stainless steel bar, perform one-pass high-nitrogen stainless steel deposition on the surface of the substrate along a predetermined deposition track; during the deposition process: control the stirring head to drive the high-nitrogen stainless steel bar to rotate, and the rotation speed v 1 is 200 - 800 r / min; apply a load axially downward along the stirring head to push the high-nitrogen stainless steel bar to feed, and the feeding speed v 2 is 10 - 50 mm / min; when controlling the stirring head to drive the high-nitrogen stainless steel bar to move along a predetermined deposition track, the moving speed v 3 is 50 - 100 mm / min; during the high-nitrogen stainless steel deposition process, argon is used for protection, and at the same time, air cooling or water cooling is used for on-line cooling; S4. Prepare at least one layer of high-nitrogen stainless steel deposition layer on the surface of the substrate (that is, the composite layer includes at least one layer of the high-nitrogen stainless steel deposition layer), and each layer of the high-nitrogen stainless steel deposition layer is formed by performing multi-pass high-nitrogen stainless steel deposition by repeating step S3.

[0030] The present invention proposes a preparation method of a high-nitrogen stainless steel-carbon steel composite plate based on friction stir deposition technology, which is used to deposit high-nitrogen stainless steel on the surface of a carbon steel plate. Friction stir deposition technology is a brand-new solid-state additive technology developed in recent years. It realizes material transfer and deposition forming through the friction and rolling between a solid metal bar and a substrate, and its additive efficiency is much higher than that of existing arc and laser additive technologies. In the additive manufacturing of high-nitrogen steel, it shows irreplaceable technical advantages; the present invention forms a high-nitrogen stainless steel deposition layer on the surface of a carbon steel plate through the friction deposition and reciprocating movement of a small-sized high-nitrogen stainless steel bar. The preparation process does not require a large-sized high-nitrogen stainless steel ingot, which simplifies the preparation difficulty of high-nitrogen stainless steel. In addition, the high-nitrogen stainless steel obtained by this solid-state surface additive comes from a strong thermoplastic deformation microstructure evolution mechanism, with fine grains and dense structure, completely avoiding metallurgical problems such as nitrogen escape and nitrogen pores.

[0031] Furthermore, by mass percentage, the chemical components contained in the high-nitrogen stainless steel ingot in step S1 are as follows: the manganese element content is 10 - 30%, the chromium element content is 10 - 25%, the molybdenum element content is 1 - 5%, the nickel element content ≤ 3%, the nitrogen element content ≥ 0.4%, and the rest is iron element.

[0032] Further, in step S3, before depositing the high-nitrogen stainless steel, the distance between the bottom end face of the stirring head and the substrate is 1-3 mm, so as to be able to limit the thickness and width of the high-nitrogen stainless steel deposition layer prepared on the substrate during the subsequent high-nitrogen stainless steel deposition process.

[0033] Further, in step S3, after the high-nitrogen stainless steel bar is controlled to stay at the initial position of the predetermined deposition track for 5-10 s, it moves along the predetermined deposition track, aiming to establish the initial additive layer.

[0034] Further, in each layer of the high-nitrogen stainless steel deposition layer prepared in step S4, there is an overlap between adjacent passes, which helps to form a dense structure between adjacent passes and avoid obvious gaps or interfaces.

[0035] Further, the overlap width is 3-5 mm. Controlling the overlap width not to exceed 5 mm can ensure the working efficiency of the whole preparation process.

[0036] Further, in step S1, the high-nitrogen stainless steel ingot is forged into the high-nitrogen stainless steel bar after solution treatment at 1100 °C.

[0037] Further, the shape of the inner hole of the stirring head is square, and the cross-sectional shape of the high-nitrogen stainless steel bar in step S1 is square and matches the shape of the inner hole of the stirring head.

[0038] The preparation method of the high-nitrogen stainless steel-carbon steel composite plate provided by the present invention plastifies the high-nitrogen stainless steel bar at high temperature through friction stir and rolling thermal deformation, and controls its flow and material transfer rate through the stirring head, and further flattens the surface of the deposition layer to form, and prepares a super-high nitrogen content stainless steel deposition layer with a nitrogen content higher than 0.40%, a grain size in the range of 2-5 μm and no holes inside, which cannot be obtained by the existing melting method; and the whole deposition process is in the solid-state thermal deformation temperature range, and the tissue evolution is completed through the dynamic recrystallization mechanism, which can effectively avoid the problems of nitrogen escape and pores, making the finally obtained high-nitrogen stainless steel deposition layer have fine grains, dense tissue and good comprehensive properties (strength and plasticity).

[0039] At the same time, by using the preparation method of the high-nitrogen stainless steel-carbon steel composite plate provided by the present invention, the process parameters can be flexibly adjusted according to the type and size of the required composite plate. The raw material is a small-size high-nitrogen stainless steel ingot that is easy to obtain, rather than a large-size high-nitrogen stainless steel plate that is difficult to obtain, as well as explosion means or large rolling equipment, with low production cost and high efficiency.

[0040] Example 1 As Figure 1As shown in the figure, this embodiment provides a method for preparing a high-nitrogen stainless steel-carbon steel composite plate. The base plate of the high-nitrogen stainless steel-carbon steel composite plate is carbon steel 4, and the composite layer is high-nitrogen stainless steel. The composite layer is prepared from a high-nitrogen stainless steel ingot. The preparation method includes the following steps: S1. Prepare a high-nitrogen stainless steel ingot and forge it into a high-nitrogen stainless steel bar 1 with a square cross-section of 10×10 mm and a length of 400 mm. The chemical composition of the high-nitrogen stainless steel ingot is as follows: the manganese element content is 20%, the chromium element content is 18%, the molybdenum element content is 2%, the nickel element content is 3%, the nitrogen element content is 0.9%, and the rest is iron element. S2. Insert the high-nitrogen stainless steel bar 1 into the square inner hole of the rotatable stirring head 2, so that the bottom surface of the high-nitrogen stainless steel bar 1 is in close contact with the surface of the base plate. A hydraulic push rod 3 for applying a load downward along the axis of the stirring head 2 to control the feeding rate of the high-nitrogen stainless steel bar 1 is connected above the stirring head 2. S3. Make the high-nitrogen stainless steel bar 1 perform a single-pass high-nitrogen stainless steel deposition on the surface of the base plate along a predetermined deposition track in a rotating and axially downward feeding state. Before performing the high-nitrogen stainless steel deposition, make the distance between the bottom end face of the stirring head 2 and the base plate be 1 - 3 mm. During the deposition process: control the stirring head 2 to drive the high-nitrogen stainless steel bar 1 to rotate, and the rotation speed v 1 is 400 r / min; apply a load downward along the axis of the stirring head 2 through the hydraulic push rod 3 to push the high-nitrogen stainless steel bar 1 to feed, and the feeding speed v 2 is 20 mm / min; when controlling the stirring head 2 to drive the high-nitrogen stainless steel bar 1 to move along the predetermined deposition track, after controlling the high-nitrogen stainless steel bar 1 to remain at the initial position of the predetermined deposition track for 5 s, then move along the predetermined deposition track, and the moving speed v 3 is 50 mm / min; during the high-nitrogen stainless steel deposition process, argon is used for protection, and at the same time, air cooling or water cooling is used for on-line cooling. S4. According to the thickness requirement, in this embodiment, two layers of high-nitrogen stainless steel deposition layers are prepared on the surface of the base plate. Each layer of the high-nitrogen stainless steel deposition layer is formed by performing multiple passes of high-nitrogen stainless steel deposition by repeating step S3, and in each layer of the high-nitrogen stainless steel deposition layer prepared, there is an overlap of 4 mm between adjacent passes. After the entire surface of the base plate is covered by the first layer of high-nitrogen stainless steel deposition layer 5, the preparation of the second layer of high-nitrogen stainless steel deposition layer 6 can be carried out.

[0041] The cross-sectional microstructure metallographic diagram of the high-nitrogen stainless steel-carbon steel composite plate prepared in this embodiment is as Figure 2As shown, the upper layer is a high-nitrogen steel stainless steel composite layer with a nitrogen content of 0.9%, and the combination Figure 2 and Figure 3 From the EBSD analysis results of the composite layer in (where EBSD is the abbreviation of "Electron Back Scatter Diffraction", indicating the backscattered electron diffraction analysis technology), it can be seen that the high-nitrogen stainless steel composite layer prepared in this embodiment has a dense structure, good bonding with the substrate, the average grain size inside the composite layer is 3.1 μm, the grains are fine, and there are no pores inside the composite layer; the tensile properties of the high-nitrogen steel stainless steel composite layer are tested, and the tensile curve is as Figure 4 shown, showing that the composite layer prepared in this embodiment has strong plasticity and good comprehensive performance, Figure 4 The two curves in show the results of repeating the tensile test on the specimens of this embodiment twice respectively, and the results show good repeatability.

[0042] Example 2 The difference between this embodiment and Example 1 is only in step S1. The chemical composition of the high-nitrogen stainless steel ingot is as follows: the manganese element content is 20%, the chromium element content is 18%, the molybdenum element content is 2%, the nickel element content is 3%, the nitrogen element content is 0.7%, and the rest is iron element.

[0043] The metallographic diagram of the cross-section structure of the high-nitrogen stainless steel-carbon steel composite plate prepared in this embodiment is as Figure 5 shown, the upper layer is a high-nitrogen steel stainless steel composite layer with a nitrogen content of 0.7%, and the combination Figure 5 and Figure 6 From the EBSD analysis results of the composite layer in, it can be seen that the high-nitrogen stainless steel composite layer prepared in this embodiment has a dense structure, good bonding with the substrate, the average grain size inside the composite layer is 4.0 μm, the grains are fine, and there are no pores inside the composite layer; the tensile properties of the high-nitrogen steel stainless steel composite layer are tested, and the tensile curve is as Figure 7 shown, showing that the composite layer prepared in this embodiment has strong plasticity and good comprehensive performance, Figure 7 The two curves in show the results of repeating the tensile test on the specimens of this embodiment twice respectively, and the results show good repeatability.

[0044] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high nitrogen stainless steel-carbon steel composite plate, characterized in that: The substrate of the high nitrogen stainless steel-carbon steel composite plate is carbon steel, the composite layer is high nitrogen stainless steel, and the composite layer is prepared by using high nitrogen stainless steel ingots; the preparation method comprises the following steps: S1. preparing a high nitrogen stainless steel ingot and forging it into a high nitrogen stainless steel bar with a cross-sectional shape matching the inner hole shape of the stirring head; S2, inserting the high nitrogen stainless steel rod into the inner hole of the stirring head so that the bottom surface of the high nitrogen stainless steel rod is in close contact with the surface of the substrate; S3, making the high nitrogen stainless steel rod rotate and feed axially downward, and deposit a high nitrogen stainless steel on the surface of the substrate along a predetermined deposition trajectory; during the deposition process: controlling the stirring head to drive the high nitrogen stainless steel rod to rotate, the rotation speed v1 is 200~800r / min; applying a load axially downward along the stirring head to push the high nitrogen stainless steel rod to feed, the feeding speed v2 is 10~50mm / min; controlling the stirring head to drive the high nitrogen stainless steel rod to move along the predetermined deposition trajectory, the moving speed v3 is 50~100mm / min; S4, preparing at least one high nitrogen stainless steel deposition layer on the surface of the substrate, each of the high nitrogen stainless steel deposition layers is formed by repeating step S3 to perform multiple passes of high nitrogen stainless steel deposition.

2. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: In terms of mass percentage, the chemical composition of the high nitrogen stainless steel ingot in step S1 is as follows: a manganese content of 10-30%, a chromium content of 10-25%, a molybdenum content of 1-5%, a nickel content of ≤3%, a nitrogen content of ≥0.4%, and the rest is iron.

3. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: In step S3, before high nitrogen stainless steel deposition is performed, the distance between the bottom end surface of the stirring head and the substrate is set to 1-3 mm.

4. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: In step S3, the high nitrogen stainless steel rod is controlled to maintain an initial position of the predetermined deposition trajectory for 5 to 10 seconds and then move along the predetermined deposition trajectory.

5. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: In each high nitrogen stainless steel deposition layer prepared in step S4, there is overlap between two adjacent passes.

6. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 5, characterized in that: The overlap width is 3~5mm.

7. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: Argon gas is used for protection during the high nitrogen stainless steel deposition process.

8. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: During the high nitrogen stainless steel deposition process, online cooling is performed by air cooling or water cooling.

9. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: In step S1, the high nitrogen stainless steel ingot is forged into the high nitrogen stainless steel bar after being solution treated at 1100°C.

10. The method for preparing a high nitrogen stainless steel-carbon steel composite plate according to claim 1, characterized in that: The inner hole shape of the stirring head is a square, and the cross-sectional shape of the high nitrogen stainless steel rod in step S1 is a square matching the inner hole shape of the stirring head.

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