A method for induction heating and rolling of a composite aluminum / steel with a thin aluminum plate as an intermediate layer

Abstract

The present application relates to a kind of methods for induction heating rolling composite aluminum / steel with thin aluminum plate as intermediate layer, comprising the following steps: S1, thin aluminum plate, thick aluminum plate, thick steel plate drilling processing;S2, surface treatment;S3, riveting preloading;S4, induction heating;S5, blank rolling;The present application can overcome the technical problems in the prior art that aluminum / steel needs single pass larger reduction ratio to realize composite, by adding thin aluminum plate between thick aluminum plate and thick steel plate, after blanking composite, it can realize thicker aluminum / steel composite under the condition of small reduction ratio rolling by induction heating, and the obtained aluminum / steel composite plate has higher bonding strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal layered composite material, and particularly relates to a method for induction heating and rolling composite aluminum / steel with thin aluminum plate as an intermediate layer. BACKGROUND

[0002] Aluminum / steel bimetal composite plate is a kind of composite plate material with aluminum alloy plate as the cladding of the composite plate and carbon steel or low alloy steel as the reinforced substrate of the composite plate. The aluminum / steel metal composite plate not only has high strength and good plasticity of steel, but also has corrosion resistance, good heat and electrical conductivity of aluminum, and gradually develops into an important research direction in the field of composite materials. The aluminum / steel bimetal composite plate has broad development space and application prospect in the industries of machinery, electronics, aerospace, automobile and the like.

[0003] At present, the rolling composite method of aluminum / steel composite plate mainly includes cold rolling and hot rolling. The aluminum / steel interface preliminary combination generally needs more than 50% single pass reduction ratio, which has a high requirement on the rolling capacity of the rolling mill for the thick specification aluminum / steel rolling composite, and the composite strength is not high in the cold rolling. In order to reduce the reduction ratio required for the composite, researchers use the hot rolling method to prepare the aluminum / steel composite plate, but the deformation resistance of the thick aluminum plate sharply decreases in the hot rolling composite, and the deformation resistance of the thick steel plate changes little, so that the deformation of the steel is particularly small and there is almost no change compared with the deformation of the aluminum. Since the deformations of the aluminum and the steel are inconsistent in the aluminum / steel rolling composite, when the thickness of each layer is large, a large shear stress is generated at the bonding interface, which is not conducive to the composite, and in addition, the thickness of the aluminum layer of the finished aluminum / steel composite plate is also difficult to control. In summary, the aluminum / steel rolling composite with thick layers is difficult to obtain high bonding strength under the condition of small reduction ratio, whether it is a cold rolling process or a hot rolling process. SUMMARY

[0004] The present application aims to provide a method for induction heating and rolling composite aluminum / steel with thin aluminum plate as an intermediate layer. The method adds a thin aluminum plate between the thick aluminum plate and the thick steel plate, uses the thick steel plate with magnetic aggregation effect to be rapidly heated to the Curie point temperature in the longitudinal magnetic induction heating, uses induction heating to rapidly heat the thick steel plate to the Curie point temperature, uses the heat transfer of the thick steel plate to make the thin aluminum plate approach the molten state, and the thick aluminum plate is still at low temperature. The rolling composite is carried out under the condition of thick aluminum plate / thin aluminum plate / thick steel plate with different temperatures, the deformation is concentrated in the thin aluminum plate in the molten state under the condition of small reduction ratio, the large deformation of the thin aluminum plate breaks the passivation film of the thick aluminum plate and the thick steel plate to be combined, promotes the high strength combination of the thin aluminum plate with the thick aluminum plate and the thick steel plate, and finally obtains the thick specification aluminum / steel composite plate.

[0005] The technical scheme adopted by the present application is as follows:

[0006] The application discloses a method for induction heating and rolling composite aluminum / steel by taking a thin aluminum plate as an intermediate layer, and comprises the following steps.

[0007] In step S1, the thin aluminum plate, the thick aluminum plate and the thick steel plate are prepared and drilled, that is, through holes are drilled in the same position at the end of the rolling mill.

[0008] In step S2, surface treatment is performed on the thin aluminum plate, the thick aluminum plate and the thick steel plate obtained in step S1.

[0009] In step S3, riveting pre-assembly is performed, that is, the plate blanks are sequentially assembled in the order of the thick aluminum plate, the thin aluminum plate and the thick steel plate, and the through holes prepared in step S1 are used to rivet and achieve riveting pre-assembly by using stainless steel rivets, so that the to-be-combined plate blanks are obtained.

[0010] In step S4, induction heating is performed on the to-be-combined plate blanks in step S3, and in the heating process, the thin aluminum plate is rapidly heated to a near-melting state through thermal conduction with the thick steel plate, while the thick aluminum plate cannot be rapidly heated in the induction heating process due to the non-ferromagnetic limitation, so that the to-be-combined plate blanks with different temperatures are obtained, that is, the temperature of the thick steel plate is much higher than that of the thin aluminum plate.

[0011] In step S5, rolling preparation is performed, that is, the to-be-combined plate blanks obtained in step S4 are rapidly pushed into the rolling mill through a guide rail, and the aluminum / steel composite plate is obtained after rolling.

[0012] Further, in step S1, the thin aluminum plate is 1060 aluminum or 5083 aluminum alloy or 6061 aluminum alloy, and the thickness is 0.5-2 mm; the thickness of the thick aluminum plate and the thick steel plate is 5-20 mm; the thick aluminum plate is 5 series or 3 series aluminum alloy; and the thick steel plate is a steel plate with a magnetic aggregation effect.

[0013] Further, step S2 specifically comprises the following steps: the thick steel plate is polished by using sandpaper or a steel wire brush to remove oxides on the surface of the thick steel plate; the thin aluminum plate and the thick aluminum plate are polished by using sandpaper to remove oxides on the surfaces of the thin aluminum plate and the thick aluminum plate, and the surfaces of the thin aluminum plate and the thick aluminum plate are wiped clean by using acetone and alcohol, and then the surfaces are dried by using a fan.

[0014] Further, in step S3, a stainless steel gasket is arranged between the thick aluminum plate and the thin aluminum plate.

[0015] Further, the thin aluminum plate and the thick aluminum plate are separated by using a 1-mm-thick stainless steel gasket with holes, so that the riveting form of the thick aluminum plate-stainless steel gasket-thin aluminum plate-thick steel plate is formed.

[0016] Further, in the step S4, the inductive heating uses a ring-shaped longitudinal magnetic induction heating coil; the inductive heating power is adjusted to a steel plate heating speed of 75-150 DEG C / s, and after heating to 750-770 DEG C, the power is kept unchanged to continue heating for 5-10 s; argon protection gas is introduced during the inductive heating.

[0017] Further, in the step S5, the rolling of the inhomogeneous temperature to-be-composited plate blank is single pass rolling by using a rolling mill; after the step S4, the inhomogeneous temperature to-be-composited plate blank is quickly pushed into the rolling mill through a guide rail, and the rolling speed is 50-200 mm / s, and the single pass reduction rate is 10%-35%.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] Compared with the prior art, the present application has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a flowchart of the method of the present application;

[0021] Figure 2 It is a schematic diagram of the to-be-composited plate blank in the method of the present application;

[0022] Figure 3 It is a schematic diagram of the guide rail of the present application;

[0023] Figure 4 It is a schematic diagram of the longitudinal magnetic induction heating coil of the present application;

[0024] Figure 5 It is a schematic diagram of the inductive heating and inhomogeneous temperature rolling of the present application;

[0025] Figure 6 It is a shear strength-strain relationship diagram of the example in which the reduction rate is 34%;

[0026] Figure 7 It is a SEM diagram of the composited interface in the example.

[0027] Wherein, the reference numerals: 1-thick aluminum plate; 2-thick steel plate; 3-thin aluminum plate. DETAILED DESCRIPTION

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] A method for induction heating rolling composite aluminum / steel with thin aluminum plate as the middle layer is provided in the present application, as shown in Figure 1 The specific implementation process is as follows:

[0030] Step S1, prepare the thick aluminum plate 1, the thick steel plate 2 and the thin aluminum plate 3 corresponding to the shape, and drill the thick aluminum plate 1, the thick steel plate 2 and the thin aluminum plate 3: that is, drill through holes at the same position of the thin aluminum plate 3, the thick aluminum plate 1 and the thick steel plate 2 entering the end of the rolling mill; wherein, the model of the thin aluminum plate 3 is 1060 aluminum or 5083 aluminum alloy or 6061 aluminum alloy, and the thickness is 0.5-2mm; the thickness of the thick aluminum plate 1 and the thick steel plate 2 is 5-20mm; the thick aluminum plate 1 is 5 series or 3 series aluminum alloy; the thick steel plate 2 is a steel plate with magnetic aggregation effect.

[0031] Step S2, surface treatment: clean the oxides and oil stains on the surfaces of the thin aluminum plate 3, the thick aluminum plate 1 and the thick steel plate 2 obtained in step S1; the specific process includes: using sandpaper or steel wire brush to polish the thick steel plate 2 to remove the oxides on the surface to be compounded; using sandpaper to polish the thin aluminum plate 3 and the thick aluminum plate 1 to remove the oxides on the surface to be compounded, and using acetone and alcohol to wipe off the oil stains on the surface, and then using a blower to dry for standby.

[0032] Step S3, riveting pre-assembly: the plate blanks are assembled in the order of thick aluminum plate-thin aluminum plate-thick steel plate; in this embodiment, the thin aluminum plate 3 and the thick aluminum plate 1 are separated by a 1mm thick stainless steel gasket with holes to form a riveting form of thick aluminum plate-stainless steel gasket-thin aluminum plate-thick steel plate; through the through hole prepared in step S1, the riveting pre-assembly of each part is realized by using stainless steel rivets to obtain the plate blank to be compounded;

[0033] Step S4, induction heating: the plate blank to be compounded in step S3 is subjected to induction heating, and the induction heating uses a ring-shaped longitudinal magnetic induction heating coil (such as Figure 3induction heating power is adjusted to the heating speed of the steel plate of 75-150℃ / s, and after the steel plate is heated to 750-770℃, the power is kept unchanged to continue heating for 5-10s; argon protection gas is introduced during the induction heating; during the heating process, the thin aluminum plate 3 can be quickly heated to a near melting state (660℃) through the heat conduction by contacting the thick steel plate 2, while the non-ferromagnetic limitation of the thick aluminum plate 1 cannot be quickly heated in the induction heating, and the low thermal conductivity of the stainless steel gasket cuts off the contact heat transfer between the thin aluminum plate 3 and the thick aluminum plate 1, so that the temperature of the thick steel plate 2 and the thin aluminum plate 3 is much higher than that of the thick aluminum plate 1, and the heterogeneous temperature composite plate blank is obtained;

[0034] Step S5, rolling preparation: the heterogeneous temperature composite plate blank obtained in step S4 is quickly pushed into a rolling mill through a guide rail, and an aluminum / steel composite plate is obtained after rolling; wherein the rolling is carried out by single pass rolling of the rolling mill; after step S4, the heterogeneous temperature composite plate blank is quickly pushed into the rolling mill (such as Figure 4 ) through the guide rail (such as Figure 5 ) shown in the figure, and the rolling speed is 50-200mm / s, and the single pass reduction rate is 10%-35%.

[0035] By preparing a shear test piece, the shear strength of the composite plate is measured to be 85MPa (such as Figure 6 ) under the condition of a reduction rate of 34% by a tensile testing machine, which reduces the requirement of the rolling capacity of the rolling mill equipment, and provides an effective solution for the effective composite of aluminum / steel under the same thickness and reduction rate.

[0036] The application will be further described below through specific examples:

[0037] An example of using 5083 thin aluminum plate to composite roll the to-be-rolled Q235 thick steel plate and the to-be-rolled 5083 thick aluminum plate; the specific process is as follows:

[0038] Step S1, drilling of thin aluminum plate, thick aluminum plate and thick steel plate: using a bench drill to drill 4mm through holes in the same position of the end of the rolling mill of the 5083 thick aluminum plate with a size of 120*40mm and a thickness of 5mm and the Q235 thick steel plate with a size of 120*40mm and a thickness of 0.5mm;

[0039] Step S2, surface treatment: polishing the Q235 thick steel plate to remove the oxides on the composite surface with sandpaper or a steel wire brush, polishing the 5083 thin aluminum plate and the 5083 thick aluminum plate to remove the oxides on the composite surface with sandpaper, and wiping the oil stains on the composite surface clean with acetone and alcohol, and then blowing dry with a blower for standby;

[0040] Step S3, riveting pre-assembly: the blanks are sequentially assembled in the order of 5083 thick aluminum plate-5083 thin aluminum plate-Q235 thick steel plate, wherein the 5083 thin aluminum plate of the to-be-combined blank is closely placed with the Q235 thick steel plate, the 5083 thin aluminum plate is separated from the 5083 thick aluminum plate by using a 1mm stainless steel spacer with holes, and riveting pre-assembly is achieved by using the stainless steel rivets in the pre-prepared through holes in step S1;

[0041] Step S4, induction heating: the to-be-combined blank in step S3 is subjected to induction heating, a longitudinal magnetic induction heating coil is used for heating, the Q235 thick steel plate transmits heat to the 5083 thin aluminum plate during the heating process, the power is adjusted to a steel plate heating speed of 75℃ / s, the power is kept unchanged after heating to 750℃ for 5s, and argon protection gas is introduced during induction heating;

[0042] Step S5, rolling preparation: after step S4 ends, the heterogeneous temperature to-be-combined blank is quickly pushed into the rolling mill through a guide rail, the rolling speed is 57.6mm / s, the reduction is 34%, argon protection gas is introduced during rolling, and the aluminum / steel double-metal composite plate is combined.

[0043] In summary, the aluminum / steel composite plate obtained by the method of the present application can be effectively combined at a lower reduction, which reduces the critical composite deformation rate and greatly reduces the capacity requirement of the rolling mill. The measured bonding strength of the aluminum / steel composite interface is greater than 85MPa. Compared with the existing one-step hot rolling or cold rolling method for preparing an aluminum / steel composite plate, the method of the present application uses a thin aluminum plate as an intermediate layer to induce heating and rolling to combine aluminum / steel, which realizes a high bonding strength of the aluminum / steel bonding interface at a small reduction by using induction heating and heterogeneous rolling to prepare an aluminum / steel composite plate. The addition of the intermediate thin aluminum plate concentrates the deformation on the thin aluminum plate, and finally realizes the production of a finished aluminum / steel composite plate with an increased thickness of the aluminum layer, which provides a feasible technical solution for the production of a multi-specification high-performance composite plate dominated by market demand in industry.

[0044] The details of the present application are well known.

[0045] The above-described embodiments are merely preferred embodiments of the present application, and do not limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the claims of the present application.

Claims

1. A method for induction heating and rolling composite aluminum / steel using a thin aluminum plate as an intermediate layer, characterized in that: Includes the following steps: Step S1: Prepare thin aluminum plates, thick aluminum plates, and thick steel plates and drill holes in them: Drill through holes at the same position at the end of the thin aluminum plates, thick aluminum plates, and thick steel plates as they enter the rolling mill. Step S2, Surface treatment: Clean the oxides and oil stains from the surfaces of the thin aluminum plate, thick aluminum plate and thick steel plate obtained in step S1; Step S3, Riveting Pre-assembly: The slabs are assembled in the order of thick aluminum plate - thin aluminum plate - thick steel plate, and riveting pre-assembly is achieved by using stainless steel rivets through the through holes pre-made in step S1 to obtain the composite slab. Step S4, Induction heating: The slab to be composited in step S3 is induction heated. During the heating process, the thin aluminum plate heats up rapidly to a near-molten state through heat conduction in contact with the thick steel plate. However, the non-ferromagnetic nature of the thick aluminum plate prevents it from heating up rapidly in induction heating. Therefore, a composite slab with different temperatures is obtained, where the temperature of the thick steel plate and the thin aluminum plate is much higher than that of the thick aluminum plate. Step S5, Rolling Preparation: The asymmetrical composite slab obtained in step S4 is quickly pushed into the rolling mill via the guide rail, and the aluminum / steel composite plate is obtained after rolling. In step S1, the thin aluminum plate is of type 1060 aluminum, 5083 aluminum alloy, or 6061 aluminum alloy, and its thickness is 0.5-2mm; the thickness of the thick aluminum plate and the thick steel plate is 5-20mm; the thick aluminum plate is a 5-series or 3-series aluminum alloy; the thick steel plate is a steel plate with a magnetic focusing effect. In step S3, a stainless steel gasket is provided between the thick aluminum plate and the thin aluminum plate.

2. The method for induction heating and rolling composite aluminum / steel with a thin aluminum plate as the intermediate layer according to claim 1, characterized in that: Step S2 specifically includes: using sandpaper or a wire brush to polish the thick steel plate to remove the oxides on its surface; using sandpaper to polish the thin aluminum plate and the thick aluminum plate to remove the oxides on their surfaces, and using acetone and alcohol to wipe the oil stains off their surfaces, and then using a fan to dry them for later use.

3. The method for induction heating and rolling composite aluminum / steel with a thin aluminum plate as the intermediate layer according to claim 1, characterized in that: The thin aluminum plate and the thick aluminum plate are separated by a 1mm thick perforated stainless steel shim, forming a riveting pattern of thick aluminum plate-stainless steel shim-thin aluminum plate-thick steel plate.

4. The method for induction heating and rolling composite aluminum / steel with a thin aluminum plate as the intermediate layer according to claim 1, characterized in that: In step S4, an annular longitudinal magnetic induction heating coil is used for induction heating; the induction heating power is adjusted to the steel plate heating rate of 75-150℃ / s, and after heating to 750-770℃, the power is kept constant and heating continues for 5-10s; argon gas is introduced as a protective gas during induction heating.

5. The method for induction heating and rolling composite aluminum / steel with a thin aluminum plate as the intermediate layer according to claim 1, characterized in that: In step S5, the slab to be composited under different temperatures is rolled using a rolling mill in a single pass. After step S4, the slab to be composited under different temperatures is quickly pushed into the rolling mill via a guide rail. The rolling speed is 50-200 mm / s, and the single pass reduction rate is 10%-35%.

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