A method for preparing thick steel-aluminum structural composite plates by combined rolling and hot pressing

Abstract

The present invention belongs to the technical field of preparation of metal structure composite materials, and specifically relates to a method for preparing a large-thickness steel-aluminum structure composite plate by combined rolling and hot pressing, comprising the following steps: S1, preparing a rolled blank; S2, preparing a steel / aluminum composite plate; S3, preparing an industrial pure aluminum / aluminum composite plate; S4, preparing a hot-pressed blank; S5, preparing the large-thickness steel-aluminum structure composite plate by hot pressing: moving a movable flat-plate induction heating device between the steel / aluminum composite plate and the industrial pure aluminum / aluminum composite plate for heating treatment; then removing the flat-plate induction heating device, starting a press for hot pressing, with a compression amount of 20% to 35%. When the compression amount reaches a predetermined value, using a pulse power supply to pass a pulse current into the steel-aluminum structure composite plate blank, and maintaining the compression state for 3 to 10 minutes, taking out the steel-aluminum structure composite plate blank and performing edge trimming treatment, and finally obtaining a large-thickness steel-aluminum structure composite plate. The present invention can realize the effective preparation of large-thickness steel-aluminum structure composite materials in small batches and multiple specifications.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of metal structure composite materials, and in particular relates to a method for preparing a thick steel-aluminum structure composite plate by combined rolling and hot pressing. Background Art

[0002] Thick steel-aluminum composites are often used for transitional connections between steel and aluminum alloy structures and have found widespread application in shipbuilding, rail transit, power systems, and new energy vehicles. Currently, thick steel-aluminum composites are primarily produced using explosive lamination, which significantly meets the demand for these materials across various industries and achieves excellent economic benefits. However, due to the significant noise pollution and the hazardous nature of explosives during explosive lamination, many developed countries have gradually banned the use of this process for the production of steel-aluminum composites. Japan, for example, has completely banned explosive lamination. Compared to explosive lamination, rolling lamination, with its advantages of high dimensional accuracy, uniform thickness ratio after lamination, and consistent and continuous bonding properties, has become the dominant trend in the production of steel-aluminum composites. Depending on the temperature of the component metals during rolling, rolling lamination can be categorized into cold rolling and hot rolling. Cold rolling is primarily used to produce steel / aluminum composite sheets with a thickness of less than 5 mm. Hot rolling, based on its forming principle, is not restricted by thickness and is more easily metallurgical. However, when the thickness difference between steel and aluminum is small, and the thickness exceeds 5mm, the difference in deformation resistance caused by the temperature rise of steel and aluminum during hot rolling will further increase, and the deformation will be mainly concentrated in the aluminum layer. It is very easy to have problems such as uncoordinated deformation and low interface bonding strength, which makes it extremely difficult to effectively prepare thick-gauge steel-aluminum structural composite materials. At the same time, the rolling composite method has great advantages in large-scale production, but is at a great disadvantage in small-batch, multi-specification production. In addition, with the continuous changes in the use environment and requirements, people's performance requirements for steel-aluminum structural composite materials are further improved. For example, large underwater and surface ships have put forward "higher welding temperature, greater bearing stress, stronger bonding interface and higher structural toughness" requirements for steel-aluminum structural composite materials. For this reason, it is urgent to develop a method for the preparation of large-thickness steel-aluminum structural composite materials that can be used in small batches and multiple specifications to achieve the effective preparation of large-thickness, high-performance steel-aluminum structural composite materials. Summary of the Invention

[0003] In view of the above problems, the present invention provides a method for preparing thick steel-aluminum structural composite plates by combining rolling and hot pressing.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0005] A method for preparing a thick steel-aluminum structural composite plate by combining rolling and hot pressing, comprising the following steps:

[0006] S1, rolling blank preparation: preparing a steel plate to be composited, a No. 1 industrial pure aluminum plate to be composited, a No. 2 industrial pure aluminum plate to be composited, and an aluminum plate to be composited, annealing the steel plate to be composited, the No. 1 industrial pure aluminum plate to be composited, the No. 2 industrial pure aluminum plate to be composited, and the aluminum plate to be composited, removing oil stains and oxide films on the surfaces of the steel plate to be composited, the No. 1 industrial pure aluminum plate to be composited, the No. 2 industrial pure aluminum plate to be composited, and the aluminum plate to be composited, drying and allowing to stand, and roughening the surfaces to be composited;

[0007] S2, Preparation of Steel / Aluminum Composite Plate: The first industrial pure aluminum plate to be composited, processed in step S1, is heated to 500-630°C, then assembled with the steel plate to be composited, and rolled using a conventional two-roll flat rolling mill or a two-roll rolling mill with knurled rollers. The steel / aluminum composite plate is then trimmed, headed, and tailed to produce a steel / aluminum composite plate having a flat or knurled surface on the industrial pure aluminum side.

[0008] S3, Preparation of Industrial Pure Aluminum / Aluminum Composite Plate: The second industrial pure aluminum plate to be composited, processed in step S1, is heated to 500-630°C, then assembled with the aluminum plate to be composited, and rolled using a conventional two-roll flat rolling mill or a two-roll rolling mill with knurled rollers. The plates are then trimmed, headed, and tailed to produce an industrial pure aluminum / aluminum composite plate having a flat or knurled surface on the industrial pure aluminum side.

[0009] S4, hot pressing blank preparation: take the steel / aluminum composite plate prepared in step S2, remove the oil stains and oxide film on the industrial pure aluminum side of the steel / aluminum composite plate, dry it, let it stand, and grind the surface to be composited to be rough; take the industrial pure aluminum / aluminum composite plate prepared in step S3, remove the oil stains and oxide film on the industrial pure aluminum side of the industrial pure aluminum / aluminum composite plate, dry it, let it stand, and grind the surface to be composited to be rough;

[0010] S5, hot pressing preparation of thick steel-aluminum composite panels: fix the steel / aluminum composite panel processed in step S4 on the upper platform of the press with the industrial pure aluminum side facing downward, and place the industrial pure aluminum / aluminum composite panel processed in step S4 on the lower platform of the press with the industrial pure aluminum side facing upward; then move the movable flat-plate induction heating device between the steel / aluminum composite panel and the industrial pure aluminum / aluminum composite panel, heat the industrial pure aluminum side of the steel / aluminum composite panel to 400-600°C, and heat the industrial pure aluminum side of the industrial pure aluminum / aluminum composite panel to 400-600°C. The aluminum surface is heated to 400-600°C; then the flat-plate induction heating device is removed, and the press is turned on to move the steel / aluminum composite plate downward, causing it to contact the industrial pure aluminum / aluminum composite plate and produce compression deformation with a compression amount of 20% to 35%, thereby forming a steel-aluminum structural composite plate blank; when the compression amount reaches a predetermined value, a pulse current is passed through the steel-aluminum structural composite plate blank using a pulse power supply, and the compression state is maintained for 3-10 minutes. The steel-aluminum structural composite plate blank is then removed and trimmed to finally obtain a thick steel-aluminum structural composite plate.

[0011] Furthermore, the steel plate to be composited in step S1 is any one of steel for ships and marine engineering, stainless steel, ordinary steel and alloy steel, with a thickness of 10 to 200 mm; the thickness of the No. 1 industrial pure aluminum plate to be composited and the No. 2 industrial pure aluminum plate to be composited is 3 to 5 mm; the aluminum plate to be composited is any one of industrial pure aluminum, 3 series aluminum alloy, 5 series aluminum alloy, and 6 series aluminum alloy, with a thickness of 10 to 200 mm; the steel plate to be composited, the No. 1 industrial pure aluminum plate to be composited, the No. 2 industrial pure aluminum plate to be composited and the aluminum plate to be composited are all in O state, and the surface roughness after polishing is Ra25 to 200.

[0012] Furthermore, in step S2, the rolling reduction ratio when preparing the steel / aluminum composite plate is 20% to 40%, and the thickness ratio of the steel plate to be composited and the No. 1 industrial pure aluminum plate to be composited is not less than 4:1.

[0013] Furthermore, in step S3, the rolling reduction ratio when preparing the industrial pure aluminum / aluminum composite plate is 20% to 40%, and the thickness ratio of the aluminum plate to be composited and the second industrial pure aluminum plate to be composited is not less than 4:1.

[0014] Furthermore, in step S4, the steel / aluminum composite plate and the industrial pure aluminum / aluminum composite plate have the same length and width.

[0015] Furthermore, the parameters of the pulse current in step S5 are: pulse width 30-100 μs, frequency 500-3000 Hz, current density amplitude 100-1000 A / mm 2 , and the electrical contact points between the press and the pulse power supply are the upper platform and the lower platform, and the upper platform and the lower platform are insulated from other parts of the press.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The present invention effectively solves the problems of uncoordinated component deformation and low bonding strength caused by large differences in component performance and small interface shearing effect when directly bonding thick steel and aluminum interfaces through a rolling-hot pressing process.

[0018] The present invention utilizes a high-temperature No. 1 industrial pure aluminum plate to be composited and a room-temperature steel plate to be composited to form a blank, performs deformation resistance limit asymmetric rolling, achieves coordinated deformation of components, and utilizes a large thickness difference to enhance the deformation of the steel-industrial pure aluminum interface, thereby achieving a strong metallurgical bonding of the steel-industrial pure aluminum interface; utilizes a high-temperature No. 2 industrial pure aluminum plate to be composited and a room-temperature aluminum plate to be composited to form a blank, performs deformation resistance limit asymmetric rolling, achieves coordinated deformation of components, and utilizes a large thickness difference to enhance the deformation of the industrial pure aluminum-aluminum interface, thereby achieving a strong metallurgical bonding of the industrial pure aluminum-aluminum interface; utilizes the characteristic that industrial pure aluminum and industrial pure aluminum are easy to bond at high temperature, and achieves a strong bonding of the industrial pure aluminum-industrial pure aluminum interface under the coupling action of high-temperature hot pressing and pulse current, while improving the bonding performance of the bonded steel-industrial pure aluminum interface and the industrial pure aluminum-aluminum interface, thereby achieving effective preparation of large-thickness steel-aluminum structural composite materials;

[0019] The present invention utilizes the characteristics that industrial pure aluminum can only form a micro-nano-scale oxide film at high temperature for a short time, and the oxide film will be torn and diffused to the composite interface during rolling, which can not only enhance the interface bonding strength but also hinder the diffusion of interface elements;

[0020] Compared with the continuous rolling composite method, the rolling-hot pressing preparation process of the present invention can realize the effective preparation of large-thickness steel-aluminum structural composite materials in small batches and multiple specifications, which can better meet market demand, with low investment, low cost and flexible production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the rolling of the steel / aluminum composite plate and the industrial pure aluminum / aluminum composite plate in Example 1 of the present invention;

[0022] Figure 2 Schematic diagram of the rolling of the steel / aluminum composite plate and the industrial pure aluminum / aluminum composite plate in Examples 2 and 3 of the present invention;

[0023] Figure 3 Schematic diagram of the hot pressing preparation process of the thick steel-aluminum composite plate of the present invention;

[0024] In the figure, industrial pure aluminum plate No. 1 to be composited - 1, steel plate to be composited - 2, knurled roller - 3, flat roller - 4, steel / aluminum composite plate - 5, industrial pure aluminum plate No. 2 to be composited - 6, aluminum plate to be composited - 7, industrial pure aluminum / aluminum composite plate - 8, upper platform - 9, flat-plate induction heating device - 10, lower platform - 11, pulse power supply - 12, and thick steel-aluminum structural composite plate - 13. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical solution of the present invention, the present invention is further described below through examples.

[0026] Example 1

[0027] like Figure 1 、 Figure 3 As shown, a method for preparing a thick steel-aluminum structural composite plate by combined rolling and hot pressing comprises the following steps:

[0028] S1, rolling blank preparation: prepare the steel plate 2 to be composited with the material of Q235 and the length × width × height of 1000mm × 500mm × 100mm; the first industrial pure aluminum plate 1 to be composited and the second industrial pure aluminum plate 6 to be composited with the material of 1060 and the length × width × height of 1100mm × 550mm × 3mm; the aluminum plate 7 to be composited with the material of 3003 and the length × width × height of 1000mm × 500mm × 100mm. The steel plate 2 was annealed at 600°C for 2 hours and then air-cooled. The first and second industrial pure aluminum plates to be composited, 1 and 6, were annealed at 400°C for 2 hours and then air-cooled. The aluminum plate 7 to be composited was annealed at 280°C for 2 hours and then air-cooled. The oil stains and oxide films on the surfaces of the steel plate 2, the first industrial pure aluminum plate to be composited, 1, the second industrial pure aluminum plate to be composited, 6, and the aluminum plate to be composited were removed. The surfaces were dried and allowed to stand, and the composited surfaces were polished to a surface roughness of Ra25.

[0029] S2, Preparation of Steel / Aluminum Composite Plate: The first industrial pure aluminum plate 1 to be composited, processed in step S1, is heated to 500°C, then assembled with the steel plate 2 to be composited, and rolled using a two-roll mill with knurled rollers 3 at a rolling reduction of 20%. The plate is then trimmed, headed, and tailed to produce a steel / aluminum composite plate 5 with a knurled surface on the industrial pure aluminum side.

[0030] S3, Preparation of Industrial Pure Aluminum / Aluminum Composite Plate: The second industrial pure aluminum plate 6 to be composited, processed in step S1, is heated to 500° C. and then assembled with the aluminum plate 7 to be composited. The plate is rolled using a two-roll mill with a knurled roller 3 at a rolling reduction of 20%. The plate is then trimmed, and the ends and ends are removed to produce an industrial pure aluminum / aluminum composite plate 8 having a knurled surface on the industrial pure aluminum side.

[0031] S4, hot pressing blank preparation: take the steel / aluminum composite plate 5 with a length × width × height of 1000 mm × 500 mm × 82.4 mm prepared in step S2, remove the oil stains and oxide film on the industrial pure aluminum side of the steel / aluminum composite plate 5, dry it and let it stand, and polish the surface to be composited to a surface roughness of Ra25; take the industrial pure aluminum / aluminum composite plate 8 with a length × width × height of 1000 mm × 500 mm × 82.4 mm prepared in step S3, remove the oil stains and oxide film on the industrial pure aluminum side of the industrial pure aluminum / aluminum composite plate 8, dry it and let it stand, and polish the surface to be composited to a surface roughness of Ra25;

[0032] S5, hot pressing preparation of large thickness steel-aluminum structural composite plate: the steel / aluminum composite plate 5 processed in step S4 is fixed on the upper platform 9 of the press with the industrial pure aluminum side facing down, and the industrial pure aluminum / aluminum composite plate 8 processed in step S4 is placed on the lower platform 11 of the press with the industrial pure aluminum side facing up, and the length and width of the steel / aluminum composite plate 5 and the industrial pure aluminum / aluminum composite plate 8 are the same; then the movable flat-plate induction heating device 10 is moved between the steel / aluminum composite plate 5 and the industrial pure aluminum / aluminum composite plate 8, and the industrial pure aluminum surface of the steel / aluminum composite plate 5 is heated to 400°C, and the industrial pure aluminum surface of the industrial pure aluminum / aluminum composite plate 8 is heated to 400°C. The steel-aluminum composite plate 5 is heated to 400°C; the flat-plate induction heating device 10 is then removed, and the press is turned on to move the steel / aluminum composite plate 5 downward so that it contacts the industrial pure aluminum / aluminum composite plate 8 and produces a compression deformation with a compression amount of 20%, thereby forming a steel-aluminum composite plate blank; when the compression amount reaches a predetermined value, a pulse current is applied to the steel-aluminum composite plate blank using a pulse power supply 12, and the electrical contact points between the press and the pulse power supply 12 are the upper platform 9 and the lower platform 11, and the upper platform 9 and the lower platform 11 are insulated from other parts of the press. The parameters of the pulse current are: pulse width 30μs, frequency 500Hz, and current density amplitude 100A / mm 2 , keep the compression state for 3 minutes, take out the steel-aluminum structure composite plate blank and perform edge trimming, and finally obtain a large thickness steel-aluminum structure composite plate 13.

[0033] Example 2

[0034] like Figure 2 、 Figure 3 As shown, a method for preparing a thick steel-aluminum structural composite plate by combined rolling and hot pressing comprises the following steps:

[0035] S1, rolling stock preparation: prepare a steel plate 2 to be composited with a length × width × height of 1000mm × 500mm × 200mm and a material of 304; a No. 1 industrial pure aluminum plate 1 to be composited with a length × width × height of 1100mm × 550mm × 5mm and a material of 1060; and a No. 1 aluminum plate 7 to be composited with a length × width × height of 1000mm × 500mm × 200mm and a material of 1060. Anneal the steel plate 2 to be composited at 600°C for 2 hours and then air-cool. Anneal the No. 1 industrial pure aluminum plate 1 to be composited and the aluminum plate 7 to be composited at 400°C for 2 hours and then air-cool. Remove oil stains and oxide films from the surfaces of the steel plate 2 to be composited, the No. 1 industrial pure aluminum plate 1 to be composited, and the aluminum plate 7 to be composited, dry and let stand, and polish the surfaces to be composited to a surface roughness of Ra50.

[0036] S2, Preparation of Steel / Aluminum Composite Plate: The first industrial pure aluminum plate 1 to be composited, processed in step S1, is heated to 550° C., then assembled with the steel plate 2 to be composited, and rolled using a conventional two-roll flat rolling mill at a rolling reduction of 30%. The plate is then trimmed, headed, and tailed to produce a steel / aluminum composite plate 5 with the industrial pure aluminum side being flat.

[0037] S3, preparation of industrial pure aluminum / aluminum composite plate: since the aluminum plate 7 to be composited is industrial pure aluminum, this step is omitted;

[0038] S4, hot pressing blank preparation: take the steel / aluminum composite plate 5 prepared in step S2 with a length × width × height of 1000 mm × 500 mm × 143.5 mm, remove the oil stains and oxide film on the industrial pure aluminum side of the steel / aluminum composite plate 5, dry and let it stand, and polish the surface to be composited to a surface roughness of Ra50;

[0039] S5, hot pressing preparation of large thickness steel-aluminum structural composite plate: the steel / aluminum composite plate 5 processed in step S4 is fixed on the upper platform 9 of the press with the industrial pure aluminum side facing downward, and the aluminum plate 7 to be composited processed in step S1 is placed on the lower platform 11 of the press, and the steel / aluminum composite plate 5 and the aluminum plate 7 to be composited are the same in length and width; then the movable flat-plate induction heating device 10 is moved between the steel / aluminum composite plate 5 and the aluminum plate 7 to be composited, and the industrial pure aluminum surface of the steel / aluminum composite plate 5 is heated to 500°C, and the aluminum surface of the aluminum plate 7 to be composited is heated to 500°C; then the flat plate is removed. The plate-type induction heating device 10 is operated by turning on the press to move the steel / aluminum composite plate 5 downward, so that it contacts the aluminum plate 7 to be composited and produces compression deformation, with a compression amount of 30%, to form a steel-aluminum composite plate blank; when the compression amount reaches a predetermined value, a pulse current is applied to the steel-aluminum composite plate blank using a pulse power supply 12. The electrical contact points between the press and the pulse power supply 12 are the upper platform 9 and the lower platform 11, and the upper platform 9 and the lower platform 11 are insulated from other parts of the press. The parameters of the pulse current are: pulse width 50 μs, frequency 1000 Hz, and current density amplitude 500 A / mm 2 , keep the compression state for 5 minutes, take out the steel-aluminum structure composite plate blank and perform edge trimming, and finally obtain a large thickness steel-aluminum structure composite plate 13.

[0040] Example 3

[0041] like Figure 2 、 Figure 3 As shown, a method for preparing a thick steel-aluminum structural composite plate by combined rolling and hot pressing comprises the following steps:

[0042] S1, rolling blank preparation: prepare the steel plate 2 to be composited with the material of Q235 and the length × width × height of 1000mm × 500mm × 10mm; the first industrial pure aluminum plate 1 to be composited and the second industrial pure aluminum plate 6 to be composited with the material of 1060 and the length × width × height of 1100mm × 550mm × 4mm; the aluminum plate 7 to be composited with the material of 3003 and the length × width × height of 1000mm × 500mm × 10mm. Plate 2 was annealed at 600°C for 2 hours and then air-cooled. The first and second industrial pure aluminum plates to be composited, 1 and 6, were annealed at 400°C for 2 hours and then air-cooled. The aluminum plate 7 to be composited was annealed at 280°C for 2 hours and then air-cooled. The oil stains and oxide films on the surfaces of the steel plate 2, the first industrial pure aluminum plate to be composited, 1, the second industrial pure aluminum plate to be composited, 6, and the aluminum plate to be composited were removed. The surfaces were dried and allowed to stand, and the composited surfaces were polished to a surface roughness of Ra200.

[0043] S2, Preparation of Steel / Aluminum Composite Plate: The first industrial pure aluminum plate 1 to be composited, processed in step S1, is heated to 630° C., then assembled with the steel plate 2 to be composited, and rolled using a conventional two-roll flat rolling mill at a rolling reduction of 40%. The plate is then trimmed, headed, and tailed to produce a steel / aluminum composite plate 5 with the industrial pure aluminum side being flat.

[0044] S3, Preparation of Industrial Pure Aluminum / Aluminum Composite Plate: The second industrial pure aluminum plate 6 to be composited, processed in step S1, is heated to 630° C., then assembled with the aluminum plate 7 to be composited, and rolled using a conventional two-roll flat rolling mill at a rolling reduction of 40%. The plate is then trimmed, headed, and tailed to produce an industrial pure aluminum / aluminum composite plate 8 having a flat industrial pure aluminum side.

[0045] S4, hot pressing blank preparation: take the steel / aluminum composite plate 5 with a length × width × height of 1000 mm × 500 mm × 8.4 mm prepared in step S2, remove the oil stains and oxide film on the industrial pure aluminum side of the steel / aluminum composite plate 5, dry and let it stand, and polish the surface to be composited to a surface roughness of Ra200; take the industrial pure aluminum / aluminum composite plate 8 with a length × width × height of 1000 mm × 500 mm × 8.4 mm prepared in step S3, remove the oil stains and oxide film on the industrial pure aluminum side of the industrial pure aluminum / aluminum composite plate 8, dry and let it stand, and polish the surface to be composited to a surface roughness of Ra200;

[0046] S5, hot pressing preparation of large thickness steel-aluminum structural composite plate: the steel / aluminum composite plate 5 processed in step S4 is fixed on the upper platform 9 of the press with the industrial pure aluminum side facing down, and the industrial pure aluminum / aluminum composite plate 8 processed in step S4 is placed on the lower platform 11 of the press with the industrial pure aluminum side facing up, and the length and width of the steel / aluminum composite plate 5 and the industrial pure aluminum / aluminum composite plate 8 are the same; then the movable flat-plate induction heating device 10 is moved between the steel / aluminum composite plate 5 and the industrial pure aluminum / aluminum composite plate 8, and the industrial pure aluminum surface of the steel / aluminum composite plate 5 is heated to 600°C, and the industrial pure aluminum surface of the industrial pure aluminum / aluminum composite plate 8 is heated to 600°C. to 600°C; then the flat-plate induction heating device 10 is removed, and the press is turned on to move the steel / aluminum composite plate 5 downward so that it contacts the industrial pure aluminum / aluminum composite plate 8 and produces compression deformation, with a compression amount of 35%, to form a steel-aluminum structural composite plate blank; when the compression amount reaches a predetermined value, a pulse current is applied to the steel-aluminum structural composite plate blank using a pulse power supply 12, and the electrical contact points between the press and the pulse power supply 12 are the upper platform 9 and the lower platform 11, and the upper platform 9 and the lower platform 11 are insulated from other parts of the press, and the parameters of the pulse current are: pulse width 100μs, frequency 3000Hz, current density amplitude 1000A / mm 2 , keep the compression state for 10 minutes, take out the steel-aluminum structure composite plate blank and perform edge trimming, and finally obtain a large thickness steel-aluminum structure composite plate 13.

[0047] The foregoing shows and describes the principal features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein.

[0048] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing thick steel-aluminum structural composite plates by combining rolling and hot pressing, characterized in that: The following steps are involved: S1, preparation of rolling blanks: preparing steel plates to be composited (2), No. 1 industrial pure aluminum plates to be composited (1), No. 2 industrial pure aluminum plates to be composited (6) and aluminum plates to be composited (7), annealing the steel plates to be composited (2), No. 1 industrial pure aluminum plates to be composited (1), No. 2 industrial pure aluminum plates to be composited (6) and aluminum plates to be composited (7), removing oil stains and oxide films on the surfaces of the steel plates to be composited (2), No. 1 industrial pure aluminum plates to be composited (1), No. 2 industrial pure aluminum plates to be composited (6) and aluminum plates to be composited (7), drying and standing, and grinding the surfaces to be composited to be rough. The steel plates to be composited (2) are for ships and Any one of marine engineering steel, stainless steel, ordinary steel and alloy steel, with a thickness of 10 to 200 mm; the thickness of the No. 1 industrial pure aluminum plate to be composited (1) and the No. 2 industrial pure aluminum plate to be composited (6) is 3 to 5 mm; the aluminum plate to be composited (7) is any one of industrial pure aluminum, 3 series aluminum alloy, 5 series aluminum alloy and 6 series aluminum alloy, with a thickness of 10 to 200 mm; the steel plate to be composited (2), the No. 1 industrial pure aluminum plate to be composited (1), the No. 2 industrial pure aluminum plate to be composited (6) and the aluminum plate to be composited (7) are all in the O state, and the surface roughness after grinding is Ra25 to 200; S2, preparation of steel / aluminum composite plate: heating the No. 1 industrial pure aluminum plate (1) to be composited processed in step S1 to 500-630°C, and then assembling it with the steel plate (2) to be composited, wherein the thickness ratio of the steel plate (2) to be composited and the No. 1 industrial pure aluminum plate (1) to be composited is not less than 4:1, and rolling is performed using a conventional two-roll flat rolling mill or a two-roll rolling mill with a knurled roller (3), with a rolling reduction rate of 20%-40%, and then trimming, removing the head and tail, to prepare a steel / aluminum composite plate (5) with a flat or knurled surface on the industrial pure aluminum side; S3, preparation of industrial pure aluminum / aluminum composite plate: heating the second industrial pure aluminum plate (6) to be composited processed in step S1 to 500-630°C, and then assembling it with the aluminum plate (7) to be composited, wherein the thickness ratio of the aluminum plate (7) to be composited to the second industrial pure aluminum plate (6) to be composited is not less than 4:1, and rolling is performed using a conventional two-roll flat rolling mill or a two-roll rolling mill with a knurled roller (3), with a rolling reduction rate of 20%-40%, and then trimming, removing the head and tail, to prepare an industrial pure aluminum / aluminum composite plate (8) with a flat or knurled surface on the industrial pure aluminum side; S4, hot pressing blank preparation: take the steel / aluminum composite plate (5) prepared in step S2, remove the oil stains and oxide film on the industrial pure aluminum side surface of the steel / aluminum composite plate (5), dry it and let it stand, and grind the surface to be composited to be rough; take the industrial pure aluminum / aluminum composite plate (8) prepared in step S3, remove the oil stains and oxide film on the industrial pure aluminum side surface of the industrial pure aluminum / aluminum composite plate (8), dry it and let it stand, and grind the surface to be composited to be rough; S5, hot pressing preparation of thick steel-aluminum structural composite plate: the steel / aluminum composite plate (5) processed in step S4 is fixed on the upper platform (9) of the press by a clamp, with the industrial pure aluminum side facing downward, and the industrial pure aluminum / aluminum composite plate (8) processed in step S4 is placed on the lower platform (11) of the press, with the industrial pure aluminum side facing upward; then the movable flat plate induction heating device (10) is moved between the steel / aluminum composite plate (5) and the industrial pure aluminum / aluminum composite plate (8), and the industrial pure aluminum side of the steel / aluminum composite plate (5) is heated to 400~600℃, and the industrial pure aluminum / aluminum composite plate ( The industrial pure aluminum surface of the steel / aluminum composite plate (8) is heated to 400-600°C; then the flat-plate induction heating device (10) is removed, and the press is turned on to move the steel / aluminum composite plate (5) downward so that it contacts the industrial pure aluminum / aluminum composite plate (8) and generates compression deformation, with a compression amount of 20%-35%, thereby forming a steel-aluminum composite plate blank; when the compression amount reaches a predetermined value, a pulse current is applied to the steel-aluminum composite plate blank using a pulse power supply (12), and the compression state is maintained for 3-10 minutes, the steel-aluminum composite plate blank is taken out and trimmed, and finally a thick steel-aluminum composite plate (13) is obtained.

2. The method for preparing thick steel-aluminum structural composite plates by combined rolling and hot pressing according to claim 1, characterized in that: In step S4, the steel / aluminum composite plate (5) and the industrial pure aluminum / aluminum composite plate (8) have the same length and width.

3. The method for preparing thick steel-aluminum structural composite plates by combined rolling and hot pressing according to claim 1, characterized in that: The parameters of the pulse current in step S5 are: pulse width 30-100 μs, frequency 500-3000 Hz, current density amplitude 100-1000 A / mm 2 , and the electrical contact points between the press and the pulse power supply (12) are the upper platform (9) and the lower platform (11), and the upper platform (9) and the lower platform (11) are insulated from other parts of the press.

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