A method for isothermal rolling composite of aluminum-clad tin bronze / steel

Abstract

The present invention belongs to the technical field of the preparation of metal laminated composites, and particularly relates to a method for preparing an aluminum-clad tin bronze / steel by differential temperature rolling, which comprises the following steps: S1, blank preparation; S2, rolling of a steel / aluminum composite plate; S3, surface treatment of the steel / aluminum composite plate; S4, rolling of a primary aluminum-clad tin bronze / steel composite plate; S5, rolling of a final-state aluminum-clad tin bronze / steel composite plate. By wrapping a thin aluminum strip on a steel plate, the present invention prevents the fresh metal on the surface of the steel plate from being oxidized due to heating, and at the same time, the plasticity of the steel plate in a high-temperature state is greatly improved, thereby reducing the deformation difference between the metal steel and copper; the introduction of the aluminum-clad layer effectively coordinates the deformation amounts of the tin bronze and the steel, making the rolling composite easier to achieve. A three-element mutual micro-scale meshing diffusion layer of steel, aluminum, and copper is formed between the component metals steel and tin bronze of the final-state aluminum-clad tin bronze / steel composite plate, and a structure in which steel-aluminum-copper and steel-copper intersect with each other is formed at the interface, improving the interface bonding performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of metal laminated composites, and particularly relates to a method for preparing an aluminum-clad tin bronze / steel by differential temperature rolling composite method. Background Art

[0002] Tin bronze is widely used in fields such as aerospace, marine vessels, and the automotive industry due to its good wear resistance, such as bushings, bearing shells, etc. However, the cost of wear-resistant parts made of single tin bronze is relatively high, which greatly limits the scope of use of tin bronze wear-resistant parts. In order to obtain wear-resistant materials with low cost and excellent performance, carbon steel is used as the steel backing material to be compounded with copper and its alloys to form steel / copper composite materials, making them have both the wear resistance of copper and the high strength of steel, which greatly promotes the development and application of wear-resistant materials.

[0003] At present, the preparation methods of steel / copper laminated composite plates mainly include explosive cladding method, casting and rolling cladding method, electroplating cladding method, and rolling cladding method, etc. The explosive cladding method has great advantages in preparing laminated composite plates with large differences in the properties of component metals, but the thickness of the products prepared is relatively large, and further rolling is often required, and the thickness of component metals is relatively thick, making it difficult to produce wear-resistant steel / copper composite plates with a relatively thin copper layer thickness. The casting and rolling cladding method is a new method for preparing laminated metal composite plates. This method has the advantages of high efficiency, short process flow, and low energy consumption, etc. However, the thickness specifications of the steel / copper laminated composite plates prepared by this method are relatively small, and interface oxidation is likely to occur, affecting the product quality. The electroplating cladding method can obtain composite coatings dispersed on the metal matrix, but the coating thickness is often relatively thin and cannot meet the requirements. Compared with other cladding methods, the rolling cladding method has the advantages of high efficiency, low cost, stable product performance, and high degree of automation, etc., and has gradually become the trend of producing metal composite materials. When preparing steel / copper composite plates by cold rolling method, a large reduction ratio is required, which has extremely high requirements for the rolling mill, and it is difficult to obtain high bonding strength; when preparing tin bronze / steel composite plates by hot rolling cladding method, the requirements for equipment are relatively low, and it is easier to obtain high bonding performance. However, during the hot rolling process, both steel and copper are prone to oxidation, resulting in poor interface bonding performance or even inability to bond.

[0004] In order to solve the problems existing in the preparation of tin bronze / steel composite materials by the rolling cladding method and obtain composite materials with more excellent comprehensive performance, it is urgent to develop a method for preparing tin bronze / steel laminated composite plates without anti-oxidation measures, high continuity, and excellent product performance. Summary of the Invention

[0005] The present invention provides a method for preparing an aluminum-clad tin bronze / steel by differential temperature rolling composite method for the above problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for isothermal rolling composite of aluminum-clad tin bronze / steel, comprising the following steps:

[0008] S1, blank preparation: Prepare thin aluminum strip, steel plate and copper plate, remove the oil stains and oxide films on the surfaces of the thin aluminum strip, steel plate and copper plate, and polish the composite surfaces of the thin aluminum strip, steel plate and copper plate rough, then leave to stand and dry.

[0009] S2, rolling of steel / aluminum composite plate: After heating the thin aluminum strip processed in step S1 to 400 - 600 °C, form a billet with the processed steel plate, make the composite surfaces of the thin aluminum strip and the steel plate contact, and enter the rolling mill for rolling, with a reduction ratio of 20 - 30%, to prepare a steel / aluminum composite plate.

[0010] S3, surface treatment of steel / aluminum composite plate: Remove the oil stains and oxide films on the aluminum side of the steel / aluminum composite plate obtained in step S2, and polish it rough, then leave to stand and dry.

[0011] S4, rolling of primary aluminum-clad tin bronze / steel composite plate: Heat the steel / aluminum composite plate processed in step S3 to 400 - 600 °C, form a billet with the copper plate processed in S1, make the composite surfaces of the steel / aluminum composite plate and the copper plate contact, and enter the rolling mill for rolling, with a reduction ratio of 20 - 40%, to prepare a primary aluminum-clad tin bronze / steel composite plate.

[0012] S5, rolling of final-state aluminum-clad tin bronze / steel composite plate: Heat the primary aluminum-clad tin bronze / steel composite plate obtained in step S4 to 400 - 650 °C, and roll it with a reduction ratio of 20 - 40%, to form a micro-scale meshing diffusion structure of three elements of steel, aluminum and copper between the steel and copper of the primary aluminum-clad tin bronze / steel composite plate, that is, the intermediate pure aluminum thin layer is cut into uneven multi-segments, so that the interface of the final-state aluminum-clad tin bronze / steel composite plate has a structure where three interfaces of steel-aluminum-copper and two interfaces of steel-copper cross each other. After straightening and trimming, the final-state aluminum-clad tin bronze / steel composite plate is obtained.

[0013] Furthermore, the steel plate in step S1 is any one of plain carbon steel, stainless steel and alloy steel, with a thickness of 6 - 40 mm; the thin aluminum strip is 1-series industrial pure aluminum or 3-series aluminum alloy, with a thickness of 0.05 - 0.2 mm; the copper plate is any one of tin phosphor bronze, tin zinc lead bronze and tin zinc lead bronze, with a thickness of 1 - 10 mm.

[0014] Still further, the surface roughness of the steel plate and the copper plate after polishing in step S1 is Ra6.3 - 200.

[0015] Even further, the surface roughness of the thin aluminum strip after polishing in step S1 is Ra6.3 - 25.

[0016] Further, after removing the oxide film on the aluminum side of the steel / aluminum composite plate in step S3, the thickness of the aluminum layer is 0.02 - 0.1 mm, and the surface roughness after grinding is Ra6.3 - 50.

[0017] Further, in the final state of the aluminum-clad tin bronze / steel composite plate in step S5, in the micro-scale meshing diffusion structure formed by the three elements of steel, aluminum, and copper between the component metals of steel and copper, the maximum thickness of the discontinuous aluminum layer does not exceed 0.05 mm.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] In the present invention, by cladding a thin aluminum strip on the steel plate, the fresh metal on the surface of the steel plate is prevented from being oxidized due to heating. At the same time, the plasticity of the steel plate in the high-temperature state is greatly improved, thereby reducing the deformation difference between the metal steel and copper; the introduction of the aluminum-clad layer effectively coordinates the deformation amounts of the tin bronze and the steel, making the rolling composite easier to be realized;

[0020] The rolling of the steel / aluminum composite plate and the rolling of the primary aluminum-clad tin bronze / steel composite plate in the present invention are both realized by differential temperature rolling, which can significantly reduce the requirements for rolling equipment; for the final state of the aluminum-clad tin bronze / steel composite plate, in the micro-scale meshing diffusion layer formed by the three elements of steel, aluminum, and copper between the component metals of steel and tin bronze, the interface forms a structure in which steel-aluminum-copper and steel-copper intersect, improving the interface bonding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the rolling of the steel / aluminum composite plate of the present invention;

[0022] Figure 2 It is a schematic diagram of the rolling of the primary aluminum-clad tin bronze / steel composite plate of the present invention;

[0023] Figure 3 It is a schematic diagram of the rolling of the final state of the aluminum-clad tin bronze / steel composite plate of the present invention;

[0024] Figure 4 It is a schematic diagram of the bonding interface of the final state of the aluminum-clad tin bronze / steel composite plate of the present invention;

[0025] In the figure, the thin aluminum strip to be compounded is 1, the thin aluminum strip roller path is 2, the first step-type heating furnace is 3, the steel plate to be compounded is 4, the pinch roll is 5, the first flat rolling mill is 6, the steel / aluminum composite plate is 7, the steel plate roller path is 8, the second step-type heating furnace is 9, the tin bronze plate to be compounded is 10, the second flat rolling mill is 11, the primary aluminum-clad tin bronze / steel composite plate is 12, the steel / aluminum composite plate roller path is 13, the third flat rolling mill is 14, the final aluminum-clad tin bronze / steel composite plate is 15, the tin bronze matrix is 16, the aluminum matrix is 17, the steel-copper two-layer interface is 18, the steel matrix is 19, and the steel-aluminum-copper three-layer interface is 20. Detailed implementation mode

[0026] In order to further elaborate the technical solution of the present invention, the present invention will be further described below through embodiments.

[0027] Embodiment 1

[0028] The steel plate used in this embodiment is Q235B steel (length × width × height is 150 mm × 80 mm × 6 mm), the thin aluminum strip used is 1060 aluminum (length × width × height is 170 mm × 100 mm × 0.05 mm), and the tin bronze plate used is QSn6.5-0.1 (length × width × height is 150 mm × 80 mm × 1 mm).

[0029] As Figures 1 to 4 shown, a method for rolling and compounding an aluminum-clad tin bronze / steel with different temperatures includes the following steps:

[0030] S1. Blank preparation: Prepare the Q235B steel plate 4 and remove the oil stain and oxide film on its surface. Grind the surface to be compounded of the Q235B steel plate 4 to be rough, and the surface roughness after grinding is Ra25; prepare the 1060 thin aluminum strip 1, remove the oil stain and oxide film on the surface of the 1060 thin aluminum strip 1, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra12.5. Prepare the QSn6.5-0.1 tin phosphor bronze plate 10, remove the oil stain and oxide film on the surface of the QSn6.5-0.1 tin phosphor bronze plate 10, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra25;

[0031] S2. Rolling of the steel / aluminum composite plate: Place the Q235B steel plate 4 processed in step S1 in a normal temperature environment and move forward under the action of the steel plate roller path 8. The 1060 thin aluminum strip 1 is heated to 400 °C by the first step-type heating furnace 3 without anti-oxidation measures and moves forward under the action of the thin aluminum strip roller path 2. At the outlet of the first step-type heating furnace 3, the surfaces to be compounded of the Q235B steel plate 4 and the 1060 thin aluminum strip 1 are in contact under the action of the pinch roll 5, and then enter the first flat rolling mill 6 for rolling. The overall reduction rate during rolling is 20%, and the Q235B / 1060 composite plate 7 is prepared;

[0032] S3, Surface treatment of the steel / aluminum composite plate: Remove the oil stain and oxide film from the aluminum side of the Q235B / 1060 composite plate 7 obtained in step S2, and grind it rough. The surface roughness after grinding is Ra12.5, the thickness of the aluminum layer is 0.03 mm, and then let it stand for drying;

[0033] S4, Rolling of the primary aluminum-layered tin bronze / steel composite plate: Heat the Q235B / 1060 composite plate 7 processed in step S3 to 400 °C in the second walking-beam reheating furnace 9, and move forward under the action of the steel / aluminum composite plate roller path 13. At the outlet of the second walking-beam reheating furnace 9, the QSn6.5-0.1 tin phosphor bronze plate 10 is stacked above the Q235B / 1060 composite plate 7, making the contact surface to be composite of the QSn6.5-0.1 tin phosphor bronze plate 10 and the rough surface of the aluminum side of the Q235B / 1060 composite plate 7, and then send it into the second four-high rolling mill 11 for rolling. The reduction ratio during the rolling process is 20%, and the primary aluminum-layered QSn6.5-0.1 / Q235B composite plate 12 is prepared;

[0034] S5, Rolling of the final-state aluminum-layered tin bronze / steel composite plate: Heat the primary aluminum-layered QSn6.5-0.1 / Q235B composite plate 12 obtained in step S4 to 400 °C and send it into the third four-high rolling mill 14 for rolling. The reduction ratio during the rolling process is 20%. A micro-scale meshing diffusion structure of three elements of steel, aluminum, and copper is formed between the steel and copper of the aluminum-layered QSn6.5-0.1 / Q235B composite plate. After straightening and trimming, the final-state aluminum-layered QSn6.5-0.1 / Q235B composite plate 15 with a thickness of 3.7 mm is obtained, and the thickness of the discontinuous aluminum layer does not exceed 0.05 mm.

[0035] Example 2

[0036] The steel plate used in this example is 06Cr19Ni10 steel (length × width × height is 10000 mm × 400 mm × 40 mm), the thin aluminum strip used is 3003 aluminum (length × width × height is 10000 mm × 420 mm × 0.2 mm), and the tin bronze plate used is QSn4-4-2.5 tin zinc lead bronze (length × width × height is 11000 mm × 400 mm × 10 mm).

[0037] As Figures 1 to 4 shown, a method for isothermal rolling and compounding of an aluminum-layered tin bronze / steel composite includes the following steps:

[0038] S1, Blank preparation: Prepare 06Cr19Ni10 steel plate 4 and remove the oil stain and oxide film on its surface. Grind the surface to be compounded of 06Cr19Ni10 steel plate 4 to be rough, and the surface roughness after grinding is Ra200; Prepare 3003 thin aluminum strip 1, remove the oil stain and oxide film on the surface of 3003 thin aluminum strip 1, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra25. Prepare QSn4-4-2.5 tin-zinc-lead bronze plate 10, remove the oil stain and oxide film on the surface of QSn4-4-2.5 tin-zinc-lead bronze plate 10, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra200;

[0039] S2, Rolling of steel / aluminum composite plate: Place the 06Cr19Ni10 steel plate 4 processed in step S1 in a normal temperature environment and move forward under the action of the steel plate roller path 8. The 3003 thin aluminum strip 1 is heated to 600°C in the first step-by-step heating furnace 3 without anti-oxidation measures and moves forward under the action of the thin aluminum strip roller path 2. At the outlet of the first step-by-step heating furnace 3, the surfaces to be compounded of the 06Cr19Ni10 steel plate 4 and the 3003 thin aluminum strip 1 come into contact under the action of the pinch roll 5, and then enter the first flat rolling mill 6 for rolling. The overall reduction rate during rolling is 30%, and the 06Cr19Ni10 / 3003 composite plate 7 is prepared;

[0040] S3, Surface treatment of steel / aluminum composite plate: Remove the oil stain and oxide film on the aluminum side of the 06Cr19Ni10 / 3003 composite plate 7 obtained in step S2, and grind it to be rough. The surface roughness after grinding is Ra50, and the thickness of the aluminum layer is 0.1 mm. Then let it stand for drying;

[0041] S4, Rolling of primary aluminum-clad layer tin bronze / steel composite plate: Heat the 06Cr19Ni10 / 3003 composite plate 7 processed in step S3 to 600°C in the second step-by-step heating furnace 9 and move forward under the action of the steel / aluminum composite plate roller path 13. At the outlet of the second step-by-step heating furnace 9, the QSn4-4-2.5 tin-zinc-lead bronze plate 10 is stacked above the 06Cr19Ni10 / 3003 composite plate 7, so that the surface to be compounded of the QSn4-4-2.5 tin-zinc-lead bronze plate 10 contacts the rough surface of the aluminum side of the 06Cr19Ni10 / 3003 composite plate 7, and then send it into the second flat rolling mill 11 for rolling. The reduction rate during rolling is 40%, and the primary 3003 aluminum-clad layer QSn4-4-2.5 / 06Cr19Ni10 composite plate 12 is prepared;

[0042] S5. Rolling of the final state aluminum-clad tin bronze / steel composite plate: Heat the primary aluminum-clad 3003 aluminum layer QSn4-4-2.5 / 06Cr19Ni10 composite plate 12 obtained in step S4 to 650 °C and feed it into the No. 3 flat rolling mill 14 for rolling. The reduction rate during the rolling process is 40%. A micro-scale meshing diffusion structure of three elements, steel, aluminum, and copper, is formed between the steel and copper of the aluminum-clad 3003 aluminum layer QSn4-4-2.5 / 06Cr19Ni10 composite plate. After straightening and trimming, the final state aluminum-clad 3003 aluminum layer QSn4-4-2.5 / 06Cr19Ni10 composite plate 15 with a thickness of 13.7 mm is obtained, and the thickness of the discontinuous aluminum layer does not exceed 0.05 mm.

[0043] Example 3

[0044] The steel plate used in this example is 304 stainless steel (length × width × height: 4000 mm × 600 mm × 20 mm), the thin aluminum strip used is 1050 aluminum (length × width × height: 4000 mm × 600 mm × 0.1 mm), and the tin bronze plate used is QSn4-3 tin-zinc bronze (length × width × height: 4000 mm × 600 mm × 6 mm).

[0045] As Figures 1 to 4 shown, a method for isothermal rolling composite of aluminum-clad tin bronze / steel includes the following steps:

[0046] S1. Blank preparation: Prepare the 304 stainless steel plate 4 and remove the oil stain and oxide film on its surface. Grind the surface to be compounded of the 304 stainless steel plate 4 to be rough, and the surface roughness after grinding is Ra6.3; Prepare the 1050 thin aluminum strip 1, remove the oil stain and oxide film on the surface of the 1050 thin aluminum strip 1, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra6.3. Prepare the QSn4-3 copper plate 10, remove the oil stain and oxide film on the surface of the QSn4-3 copper plate 10, and grind the surface to be compounded to be rough, and the surface roughness after grinding is Ra6.3;

[0047] S2. Rolling of the steel / aluminum composite plate: Place the 304 stainless steel plate 4 processed in step S1 in a normal temperature environment and move forward under the action of the steel plate roller path 8. The 1050 thin aluminum strip 1 is heated to 500 °C by the No. 1 step-by-step heating furnace 3 without anti-oxidation measures and moves forward under the action of the thin aluminum strip roller path 2. At the outlet of the No. 1 step-by-step heating furnace 3, the surfaces to be compounded of the 304 stainless steel plate 4 and the 1050 thin aluminum strip 1 are contacted under the action of the pinch roll 5 and then enter the No. 1 flat rolling mill 6 for rolling. The overall reduction rate during the rolling process is 25%, and the 304 / 1050 composite plate 7 is prepared;

[0048] S3, Surface treatment of the steel / aluminum composite plate: Remove oil stains and oxide films from the aluminum side of the 304 / 1050 composite plate 7 obtained in step S2, and grind it rough. The surface roughness after grinding is Ra6.3, the thickness of the aluminum layer is 0.06 mm, and then let it stand for drying.

[0049] S4, Rolling of the primary aluminum layer-containing tin bronze / steel composite plate: Heat the 304 / 1050 composite plate 7 treated in step S3 to 500 °C in the second walking beam reheating furnace 9, and move forward under the action of the steel / aluminum composite plate roller table 13. At the outlet of the second walking beam reheating furnace 9, the QSn4-3 copper plate 10 is stacked above the 304 / 1050 composite plate 7, so that the surface to be composite of the QSn4-3 copper plate 10 contacts the rough surface of the aluminum side of the 304 / 1050 composite plate 7, and then send it into the second four-high rolling mill 11 for rolling. The reduction ratio during the rolling process is 30%, and the primary aluminum layer-containing QSn4-3 / 304 composite plate 12 is prepared.

[0050] S5, Rolling of the final aluminum layer-containing tin bronze / steel composite plate: Heat the primary aluminum layer-containing QSn4-3 / 304 composite plate 12 obtained in step S4 to 500 °C and send it into the third four-high rolling mill 14 for rolling. The reduction ratio during the rolling process is 30%. A micro-scale meshing diffusion structure of three elements of steel, aluminum, and copper is formed between the steel and copper of the aluminum layer-containing QSn4-3 / 304 composite plate. After straightening and trimming, the final aluminum layer-containing QSn4-3 / 304 composite plate 15 with a thickness of 10.3 mm is obtained, and the thickness of the discontinuous aluminum layer does not exceed 0.05 mm.

[0051] The above shows and describes the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0052] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for isothermal rolling and compounding of aluminum-clad tin bronze / steel, characterized in that, it includes the following steps: S1, blank preparation: Prepare a thin aluminum strip, a steel plate and a copper plate. The thickness of the thin aluminum strip is 0.05~0.2 mm, the thickness of the steel plate is 6~40 mm, and the thickness of the copper plate is 1~10 mm. Remove the oil stains and oxide films on the surfaces of the thin aluminum strip, the steel plate and the copper plate, and polish the bonding surfaces of the thin aluminum strip, the steel plate and the copper plate rough, then leave them standing for drying. The surface roughness of the polished steel plate and copper plate is Ra6.3~200, and the surface roughness of the polished thin aluminum strip is Ra6.3~25; S2, rolling of steel / aluminum composite plate: After heating the thin aluminum strip processed in step S1 to 400~600°C, form a blank with the processed steel plate, make the bonding surfaces of the thin aluminum strip and the steel plate contact, and enter the rolling mill for rolling, with a reduction rate of 20~30%, to prepare a steel / aluminum composite plate; S3, surface treatment of steel / aluminum composite plate: Remove the oil stains and oxide films on the aluminum side of the steel / aluminum composite plate obtained in step S2, and polish it rough, then leave it standing for drying. After removing the oxide film on the aluminum side of the steel / aluminum composite plate, the thickness of the aluminum layer is 0.02~0.1 mm, and the surface roughness after polishing rough is Ra6.3~50; S4, rolling of primary aluminum-clad tin bronze / steel composite plate: Heat the steel / aluminum composite plate processed in step S3 to 400~600°C, form a blank with the copper plate processed in S1, make the bonding surfaces of the steel / aluminum composite plate and the copper plate contact, and enter the rolling mill for rolling, with a reduction rate of 20~40%, to prepare a primary aluminum-clad tin bronze / steel composite plate; S5, rolling of final-state aluminum-clad tin bronze / steel composite plate: Heat the primary aluminum-clad tin bronze / steel composite plate obtained in step S4 to 400~650°C, and roll it with a reduction rate of 20~40% to form a micro-scale meshing and diffusion structure of three elements of steel, aluminum and copper between the steel and copper of the primary aluminum-clad tin bronze / steel composite plate, that is, the intermediate pure aluminum thin layer is cut into uneven multi-segments, so that there is a structure in which three-layer interfaces of steel-aluminum-copper and two-layer interfaces of steel-copper cross each other at the interface of the final-state aluminum-clad tin bronze / steel composite plate. After straightening and trimming, the final-state aluminum-clad tin bronze / steel composite plate is obtained.

2. A method for isothermal rolling and compounding of aluminum-clad tin bronze / steel according to claim 1, characterized in that, the steel plate in step S1 is any one of plain carbon steel, stainless steel, and alloy steel; the thin aluminum strip is 1-series industrial pure aluminum or 3-series aluminum alloy; the copper plate is any one of tin phosphor bronze, tin zinc lead bronze, and tin zinc lead bronze.

3. A method for isothermal rolling and compounding of aluminum-clad tin bronze / steel according to claim 1, characterized in that, in the final-state aluminum-clad tin bronze / steel composite plate in step S5, in the micro-scale meshing and diffusion structure of three elements of steel, aluminum and copper formed between the component metals of steel and copper, the thickness of the discontinuous aluminum layer does not exceed 0.05 mm.

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