Steel-aluminum composite plate strip for high-temperature brazing and its preparation process

Abstract

The object of the present invention is to disclose a steel-aluminum composite strip for high-temperature brazing and its preparation process. The steel-aluminum composite strip includes an aluminum strip and a steel strip. The thickness of the steel-aluminum composite strip is 0.15 mm - 3.0 mm. The proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite strip is 5% - 70%, and the thickness of the aluminum strip > 0.1 mm. The composition of the aluminum strip includes Si: 0.6 wt% - 1.8 wt%, Fe: 0.3 wt% - 1.2 wt% and rare earth: 0.5 wt% - 1 wt%. The composition of the steel strip includes C: 0.05 wt% - 0.4 wt% and Mn: 0.2 wt% - 1.0 wt%. Compared with the prior art, the beneficial effects of this embodiment are: (1) The technical solution of the present invention adjusts the chemical compositions of the aluminum strip and the steel strip to make their interfacial wetting performance more conducive to compounding, solving the key technology of the steel-aluminum composite interface; (2) Creatively pre-heats the steel strip and the aluminum strip, that is, adopts a hot-rolling compounding process of high-temperature semi-liquid steel-aluminum compounding to realize the stable, short-process and high-efficiency production of a steel-aluminum composite strip with a width of 600 mm - 1500 mm and a thickness of 0.15 mm - 3.0 mm, and the proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite strip is 5% - 70%.

Description

Technical Field

[0001] The present invention relates to the technical field of metal composite materials, and particularly relates to a steel-aluminum composite plate strip for high-temperature brazing and a preparation process thereof. Background Art

[0002] With the rapid development of new energy vehicles and the energy storage industry, the weight, volume of battery packs and battery modules are getting heavier and larger, and the charging time is getting shorter. Therefore, higher requirements are put forward for the thermal management of battery packs and battery modules. It has become inevitable to use a liquid cooling plate structure for heat exchange. At present, the liquid cooling plate adopts an aluminum alloy brazing process. When the brazing temperature exceeds 600 °C, the strength and impact resistance of the liquid cooling plate cannot meet the requirements.

[0003] Both steel and aluminum are important basic metal materials, which are widely used in industrial, civil and other fields. Aluminum has good electrical and thermal conductivity, and steel has good heat resistance and relatively high strength; the steel-aluminum composite plate strip combines the thermal conductivity, low-temperature welding and lightweight properties of aluminum, as well as the high chemical stability, good high strength, impact resistance and high-temperature resistance of steel, and has a wide range of uses, such as being applied to automobiles, lithium battery packs, energy storage thermal management, etc.

[0004] At present, the steel-aluminum composite metal plate strip mainly adopts a solid-solid composite method or a liquid-solid composite method. The solid-solid composite method includes an explosive composite method, a cladding welding method, a composite ingot hot rolling method, a rolling pressure connection method, etc.; in the production of steel-aluminum composite plate strips, low-temperature composite or cold rolling composite is mainly adopted, resulting in defects such as low composite strength of the composite plate strip, small width, easy delamination during high-temperature brazing, and poor stamping performance.

[0005] In view of this, it is necessary to develop a steel-aluminum composite plate strip for high-temperature brazing and a preparation process thereof to overcome the above defects. Summary of the Invention

[0006] The purpose of the present invention is to disclose a steel-aluminum composite plate strip for high-temperature brazing and a preparation process thereof.

[0007] The first object of the present invention is to provide a steel-aluminum composite plate strip for high-temperature brazing.

[0008] The second object of the present invention is to provide a preparation process for a steel-aluminum composite plate strip for high-temperature brazing.

[0009] To achieve the above first object of the invention, the present invention provides a steel-aluminum composite plate strip for high-temperature brazing. The steel-aluminum composite plate strip includes an aluminum strip and a steel strip. The thickness of the steel-aluminum composite plate strip is 0.15 mm - 3.0 mm. The proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite plate strip is 5% - 70%, and the thickness of the aluminum strip > 0.1 mm;

[0010] The composition of the aluminum strip includes Si: 0.6wt%-1.8wt%, Fe: 0.3wt%-1.2wt%, and rare earth: 0.5wt%-1wt%.

[0011] The composition of the steel strip includes C: 0.05wt%-0.4wt% and Mn: 0.2wt%-1.0wt%.

[0012] Preferably, the rare earth is at least one of lanthanum, cerium, or neodymium.

[0013] Based on the same inventive principle, to achieve the above second inventive purpose, the present invention provides a preparation process for a steel-aluminum composite plate strip for high-temperature brazing, including the following steps:

[0014] Heat an aluminum strip including Si: 0.6wt%-1.8wt%, Fe: 0.3wt%-1.2wt%, and rare earth: 0.5wt%-1wt% to 100°C - 450°C;

[0015] Heat a steel strip including C: 0.05wt%-0.4wt% and Mn: 0.2wt%-1.0wt% to 300°C - 650°C, and the thickness of the steel strip is 0.3mm - 3.2mm;

[0016] Hot-roll and compound the heated aluminum strip and the heated steel strip to obtain a first steel-aluminum composite plate strip, and the thickness of the first steel-aluminum composite plate strip is 0.2mm - 3.5mm;

[0017] The first steel-aluminum composite plate strip is subjected to intermediate annealing, cold rolling, and final annealing in sequence to obtain a steel-aluminum composite plate strip;

[0018] The thickness of the steel-aluminum composite plate strip is 0.15mm - 3.0mm, and the proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite plate strip is 5% - 70%.

[0019] Preferably, the following steps are further included:

[0020] The aluminum strip is subjected to texturing treatment before heating, and the roughness of the aluminum strip is 30 mesh - 60 mesh;

[0021] The steel strip is subjected to texturing treatment before heating, and the roughness of the steel strip is 30 mesh - 60 mesh.

[0022] Preferably, the intermediate annealing temperature is 350°C - 550°C, the holding time is 1h - 5h; the cold rolling reduction rate is 10% - 30% per pass; the final annealing temperature is 500°C - 550°C.

[0023] Preferably, the speed of the hot-roll compounding is 2m / min - 20m / min.

[0024] Preferably, the thickness reduction rate of the hot-rolled composite is 20% / pass - 50% / pass.

[0025] Preferably, the rolling force of the hot-rolled composite is 1000t - 2700t.

[0026] Preferably, the speed of the cold rolling is 100m / min - 300m / min, and the thickness reduction rate of the first pass of the cold rolling is 10% - 30%.

[0027] Preferably, the surface of the rolling roll used for the hot-rolled composite is coated with lubricating oil.

[0028] Compared with the prior art, the beneficial effects of this embodiment are as follows:

[0029] (1) Through adjusting the chemical compositions of the aluminum strip and the steel strip, the technical solution of the present invention makes the interfacial wetting performance more conducive to composite, and solves the key technology of the steel-aluminum composite interface.

[0030] (2) Creatively pre-heat the steel strip and the aluminum strip, that is, adopt the hot-rolled composite process of high-temperature semi-liquid steel-aluminum composite to realize the stable, short-process and high-efficiency production of steel-aluminum composite plate strips with a width of 600mm - 1500mm and a thickness of 0.15mm - 3.0mm, and the proportion of the aluminum strip thickness in the thickness of the steel-aluminum composite plate strip is 5% - 70%, and the aluminum strip thickness > 0.1mm.

[0031] (3) The steel-aluminum composite plate strip for high-temperature brazing has high strength, stable composite interface, high composite strength, elongation rate ≥ 17%, and good stamping performance. At the brazing temperature of 600°C - 620°C and the brazing time of 5min - 20min, the steel-aluminum composite plate strip does not delaminate, meeting the requirements of the liquid cooling plate for high-temperature brazing, high strength and light weight, and excellent stamping performance of the material, and is widely used in automobiles, lithium battery packs, energy storage thermal management, etc., with remarkable economic benefits.

[0032] (4) In the steel-aluminum composite plate strip for high-temperature brazing of the present invention, the proportion of the aluminum strip thickness reaches 5% - 70%, and it does not delaminate after repeated bending. The elongation rate of the steel-aluminum composite plate strip ≥ 17%, and the composite peel strength ≥ 20N / mm. Description of the Drawings

[0033] Figure 1 It is a cross-sectional view of the steel-aluminum composite plate strip for high-temperature brazing of the present invention.

[0034] Figure 2 It is a schematic preparation principle diagram of the steel-aluminum composite plate strip for high-temperature brazing of the present invention.

[0035] Figure 3 It is a process flow chart of the preparation of the steel-aluminum composite plate strip for high-temperature brazing of the present invention.

[0036] Among them, 1. aluminum strip; 2. steel strip; 3. rolling roll. Specific embodiments

[0037] The present invention will be described in detail below in conjunction with the embodiments shown in the drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Any equivalent transformation or substitution in terms of function, method, or structure made by those of ordinary skill in the art based on these embodiments shall fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0039] Example 1

[0040] See Figure 1 This embodiment provides a steel-aluminum composite plate strip for high-temperature brazing. The steel-aluminum composite plate strip includes an aluminum strip 1 and a steel strip 2. The thickness of the steel-aluminum composite plate strip is 0.15 mm - 3.0 mm. The proportion of the thickness of the aluminum strip 1 in the thickness of the steel-aluminum composite plate strip is 5% - 70%. The thickness of the aluminum strip > 0.1 mm. The composition of the aluminum strip 1 includes Si: 0.6 wt% - 1.8 wt%, Fe: 0.3 wt% - 1.2 wt%, and rare earth. The rare earth is at least one of lanthanum, cerium, or neodymium, and the rare earth content is 0.5 wt% - 1 wt%. The composition of the steel strip 2 includes C: 0.05 wt% - 0.4 wt% and Mn: 0.2 wt% - 1.0 wt%.

[0041] Specifically, referring to Table 1, Table 1 shows the composition and thickness of the steel-aluminum composite plate strip. The role of Si in the aluminum strip is to enhance the interfacial wettability between the aluminum strip and the steel strip. Fe and rare earths together play a role in refining the grains of the aluminum strip alloy, improving the wettability of the steel-aluminum composite, and enhancing the toughness of the aluminum strip. The role of C in the steel strip is to inhibit the formation of brittle phase layers between steel and aluminum during brazing, and the role of Mn is to increase the strength. The performance tests of several embodiments in Table 1 show that the steel-aluminum composite plate strip for high-temperature brazing has high strength, a stable composite interface, high composite strength, an elongation rate ≥ 17%, a composite peel strength ≥ 20 N / mm, and good stamping performance. At a maximum brazing temperature of 620 °C and a brazing time of 5 min - 20 min, the steel-aluminum composite plate strip does not delaminate, meeting the requirements of the liquid cooling plate for high-temperature brazing, high strength and light weight, and excellent stamping performance of the material. It is widely used in automobiles, lithium battery packs, energy storage thermal management, etc., with significant economic benefits.

[0042] Table 1 Composition and Thickness of Steel-Aluminum Composite Plate Strip

[0043]

[0044] Example 2

[0045] Referring to Figure 2 and Figure 3 , this embodiment provides a preparation process for a steel-aluminum composite plate strip for high-temperature brazing, including the following steps:

[0046] Step S1: The aluminum strip is subjected to surface texturing before heating. The surface roughness of the aluminum strip is 30 mesh - 60 mesh. The aluminum strip containing Si: 0.6 wt% - 1.8 wt%, Fe: 0.3 wt% - 1.2 wt%, and rare earth: 0.5 wt% - 1 wt% is heated to 100 °C - 450 °C. Specifically, the aluminum strip is heated to 100 °C - 450 °C to make the aluminum strip itself have a certain amount of heat and be in a high-temperature semi-liquid state. During heating, a nitrogen-hydrogen mixed gas is used for protection to prevent the aluminum strip from being oxidized. The surface texturing helps to increase the bonding force between steel and aluminum, and the surface texturing is carried out by sanding with a sand belt or a wire wheel.

[0047] Step S2: The steel strip is subjected to surface texturing before heating. The surface roughness of the steel strip is 30 mesh - 60 mesh. The steel strip containing C: 0.05 wt% - 0.4 wt% and Mn: 0.2 wt% - 1.0 wt% is heated to 300 °C - 650 °C, and the thickness of the steel strip is 0.3 mm - 3.2 mm. Specifically, the steel strip is heated to 300 °C - 650 °C to make the steel strip itself have a certain amount of heat and be in a high-temperature reducing atmosphere. During heating, a nitrogen-hydrogen mixed gas is used for protection to prevent the aluminum strip from being oxidized. The surface texturing helps to increase the bonding force between steel and aluminum, and the surface texturing is carried out by sanding with a sand belt or a wire wheel.

[0048] Step S3: Hot-roll and compound the heated aluminum strip and the heated steel strip to obtain a first steel-aluminum composite strip, with the thickness of the first steel-aluminum composite strip being 0.2 mm - 3.5 mm; specifically, the surface of the rolling roll 3 used for the hot-roll compounding is coated with lubricating oil to prevent the aluminum strip from adhering to the surface of the rolling roll; the speed of the hot-roll compounding is 2 m / min - 20 m / min, preferably 8 m / min, the reduction rate of the hot-roll compounding is 20% / pass - 50% / pass, preferably 35% / pass, and the rolling force of the hot-roll compounding is 1000 t - 2700 t, preferably 1800 t; in steps S1 - S3, the steel strip and the aluminum strip are creatively pre-heated, that is, a hot-roll compounding process of high-temperature semi-liquid steel-aluminum compounding is adopted, and with the cooperation of the rolling force and the reduction rate, a steel-aluminum composite strip with a width of 600 mm - 1500 mm and a thickness ratio of up to 5% - 70% can be stably produced with a short process and high efficiency.

[0049] Step S4: The first steel-aluminum composite strip is successively subjected to intermediate annealing, cold rolling, and finish annealing to obtain a steel-aluminum composite strip, with the thickness of the steel-aluminum composite strip being 0.15 mm - 3.0 mm, and the thickness ratio of the aluminum strip to the thickness of the steel-aluminum composite strip being 5% - 70%; specifically, the speed of the cold rolling is 100 m / min - 300 m / min, preferably 190 m / min, the reduction rate of the first pass of the cold rolling is 10% - 30%, preferably 17%; the intermediate annealing temperature is 350°C - 550°C, preferably 410°C, and the holding time is 1 h - 5 h; the reduction rate of the cold rolling is 10% / pass - 30% / pass, preferably 21% / pass; the finish annealing temperature is 500°C - 550°C; after step S4, the steel-aluminum composite strip for high-temperature brazing has high strength, a stable composite interface, high composite strength, an elongation rate ≥ 17%, and good stamping performance. At a brazing temperature of 600°C - 620°C and a brazing time of 5 min - 20 min, the steel-aluminum composite strip does not delaminate, meeting the requirements of the liquid cooling plate for high-temperature brazing, high strength and light weight, and excellent stamping performance of the material, and is widely used in automobiles, lithium battery packs, energy storage thermal management, etc., with remarkable economic benefits.

[0050] Refer to Table 2. Table 2 shows the finished product composition and thickness of the steel-aluminum composite strip. In Table 2, the speed of the hot-roll compounding is 5 m / min, the reduction rate of the hot-roll compounding is 25% / pass, and the rolling force of the hot-roll compounding is 1500 t; the speed of the cold rolling is 130 m / min, and the reduction rate of the first pass of the cold rolling is 18%; the intermediate annealing temperature is 450°C, and the holding time is 3 h; the reduction rate of the cold rolling is 20% / pass; the finish annealing temperature is 510°C.

[0051] Table 2 Finished Product Composition and Thickness of the Steel-Aluminum Composite Strip

[0052]

Claims

1. Steel-aluminum composite plate strip for high-temperature brazing, Characterized in that, The steel-aluminum composite plate strip comprises an aluminum strip and a steel strip, the thickness of the steel-aluminum composite plate strip is 0.15 mm - 3.0 mm, the proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite plate strip is 30% - 70%, and the thickness of the aluminum strip > 0.1 mm; The composition of the aluminum strip consists of Si: 1.5 wt% - 1.8 wt%, Fe: 1.0 wt% - 1.2 wt%, rare earth: 0.6 wt% - 1 wt% and aluminum. The role of Si in the aluminum strip is to enhance the interfacial wettability of the composite of the aluminum strip and the steel strip; The composition of the steel strip includes C: 0.05 wt% - 0.4 wt% and Mn: 0.5 wt% - 1.0 wt%; The steel-aluminum composite plate strip is used for a liquid cooling plate, the elongation of the steel-aluminum composite plate is ≥17%, and the composite peeling strength is ≥20 N / mm; The steel-aluminum composite plate does not delaminate at a brazing temperature of 620 °C and a brazing time of 5 min - 20 min.

2. The steel-aluminum composite plate strip for high-temperature brazing according to claim 1, Characterized in that, The rare earth is at least one of lanthanum, cerium or neodymium.

3. Preparation process of steel-aluminum composite plate strip for high-temperature brazing, Characterized in that, It includes the following steps: The aluminum strip is subjected to surface texturing before heating, and the surface roughness of the aluminum strip is 30 mesh - 60 mesh; Heat the aluminum strip composed of Si: 1.5 wt% - 1.8 wt%, Fe: 1.0 wt% - 1.2 wt%, rare earth: 0.6 wt% - 1 wt% and aluminum to 100 °C - 250 °C. The role of Si in the aluminum strip is to enhance the interfacial wettability of the composite of the aluminum strip and the steel strip; The steel strip is subjected to surface texturing before heating, and the surface roughness of the steel strip is 30 mesh - 60 mesh; Heat the steel strip including C: 0.05 wt% - 0.4 wt% and Mn: 0.2 wt% - 1.0 wt% to 300 °C - 400 °C, and the thickness of the steel strip is 0.3 mm - 3.2 mm; Hot-roll and composite the heated aluminum strip and the heated steel strip to obtain a first steel-aluminum composite plate strip. The thickness of the first steel-aluminum composite plate strip is 0.2 mm - 3.5 mm, the speed of the hot-roll composite is 2 m / min - 5 m / min, and the rolling force of the hot-roll composite is 1500 t - 2700 t; The first steel-aluminum composite plate strip is subjected to intermediate annealing, cold rolling and finish annealing in sequence to obtain a steel-aluminum composite plate strip; The thickness of the steel-aluminum composite plate strip is 0.15 mm - 1.0 mm, the proportion of the thickness of the aluminum strip in the thickness of the steel-aluminum composite plate strip is 5% - 70%. The steel-aluminum composite plate strip is used for a liquid cooling plate, the elongation of the steel-aluminum composite plate is ≥17%, the composite peeling strength is ≥20 N / mm, and the steel-aluminum composite plate does not delaminate at a brazing temperature of 620 °C and a brazing time of 5 min - 20 min.

4. The preparation process of the steel-aluminum composite plate strip for high-temperature brazing according to claim 3, Characterized in that, The intermediate annealing temperature is 350 °C - 550 °C, and the holding time is 1 h - 5 h; the cold rolling reduction rate is 10% - 30% / pass; the finish annealing temperature is 500 °C - 550 °C.

5. The preparation process of the steel-aluminum composite plate strip for high-temperature brazing as described in claim 4, characterized in that, the reduction rate of the hot rolling composite is 20% / pass - 50% / pass.

6. The preparation process of the steel-aluminum composite plate strip for high-temperature brazing as described in claim 4, characterized in that, the speed of the cold rolling is 100m / min - 300m / min, and the reduction rate of the first pass of the cold rolling is 10% - 30%.

7. The preparation process of the steel-aluminum composite plate strip for high-temperature brazing as described in claim 4, characterized in that, the surface of the rolling roll used for the hot rolling composite is coated with lubricating oil.

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