Aluminum alloy composite material for brazing and preparation method thereof

Abstract

The invention relates to the field of aluminum alloy material manufacturing, and discloses an aluminum alloy composite material for brazing and a preparation method thereof.The aluminum alloy composite material for brazing is made of a multi-layer composite material and comprises a core material, a first composite layer and a second composite layer, and the alloy of the core material comprises, by mass, 0.8-1.1% of Si, 0.5-0.7% of Cu, 1.5-1.8% of Mn, 1t and the balance Al; 0.3% of Fe, lt; the mass fraction of a single element is smaller than or equal to 0.05%, and the mass fraction of other elements is smaller than or equal to 0.15%. The alloy of the composite layer I comprises the following components in percentage by mass: 9.0-11.0% of Si, lt; 0.3% of Fe, lt; 0.15% of Cu, lt; 0.1% of Zn, less than or equal to 0.05% of a single element, and the balance of aluminum; the alloy of the composite layer II comprises the following components in percentage by mass: 0.3 to 0.5 percent of Si, lt; the aluminum alloy comprises the following components in percentage by weight: 0.3% of Fe, 3.5-4.5% of Zn, 0.9-1.3% of Ni, other elements less than or equal to 0.05% of a single element, and the balance of aluminum. The aluminum alloy composite material is excellent in composite interface, uniform in composite layer distribution and good in corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the field of aluminum alloy material manufacturing, and specifically relates to an aluminum alloy composite material for brazing and a preparation method thereof. Background Art

[0002] As the material becomes thinner, the thickness of the composite layer used for brazing and corrosion protection needs to increase, which requires the composite layer to be designed to be relatively thick. The traditional method of directly combining the ingot with the composite layer results in a very thick composite blank, which brings great difficulties to the composite process. The composited product has many defects, which is not conducive to improving the yield rate. Summary of the invention

[0003] In order to solve the above problems, the present invention provides an aluminum alloy composite material for brazing and a preparation method thereof. The specific technical scheme is as follows:

[0004] A brazing aluminum alloy composite material, the brazing aluminum alloy composite material is made of a multilayer composite material, the multilayer composite material comprises a core material, a composite layer 1 and a composite layer 2, the alloy of the core material comprises (mass fraction ratio): 0.8-1.1% Si, 0.5-0.7% Cu, 1.5-1.8% Mn, <0.3% Fe, <0.1% Ti, the mass fraction of a single element is ≤0.05% and the mass fraction of other elements is ≤0.15%, and the balance is aluminum;

[0005] The alloy of the composite layer 1 comprises (by mass fraction): 9.0-11.0% Si, <0.3% Fe, <0.15% Cu, <0.1% Zn, ≤0.05% of other elements, and the balance is aluminum;

[0006] The alloy of the composite layer 2 comprises (mass fraction ratio): 0.3 to 0.5% Si, <0.3% Fe, 3.5 to 4.5% Zn, 0.9 to 1.3% Ni, ≤0.05% of other elements for a single element, and the balance is aluminum;

[0007] As a further improvement, it is characterized in that: the composite layer 1 is located on the outer surface of the core material, and the composite layer 2 is located on the inner surface of the core material.

[0008] As a further improvement, it is characterized in that the thickness of the composite layer 1 and the composite layer 2 are respectively 12% and 16% of the thickness of the multi-layer composite material.

[0009] A method for preparing the above-mentioned aluminum alloy composite material for brazing, wherein the method comprises the following steps:

[0010] Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape;

[0011] Step 2: Saw the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product with a thickness of 450mm;

[0012] Step 3: The aluminum product in step 2 is hot-rolled to produce a thinner aluminum product with a thickness of 300 mm. This step greatly reduces the thickness of the core material layer, reduces the difficulty of compounding, and is more cost-effective than the traditional method of directly purchasing a crystallizer.

[0013] Step 4: Take the aluminum product in step 3 as the core material and stack two layers of composite plates on top and bottom for composite and hot rolling, and roll them into a hot-rolled coil with a specified specification of 5.0 mm thickness, and continue cold rolling to reach an intermediate thickness of 0.23 mm;

[0014] Step 5: annealing the coil in step 4;

[0015] Step 6: cold rolling the coil in step 5 to a final thickness of 0.2 mm;

[0016] Step 7: Straighten the coiled material in step 5;

[0017] Step 8: Cut and shape the coiled material in step 7.

[0018] As a further improvement, it is characterized in that: in the step 3, the straightness of the aluminum product needs to be controlled to be less than or equal to 0.2 mm / m, and a secondary milling is performed.

[0019] The present invention provides an aluminum alloy composite material for brazing and a preparation method thereof, which solves the process difficulties in the preparation process of high composite ratio materials by hot rolling a primary core material ingot to obtain a thinner core material ingot, which is then composited with upper and lower plates, and then hot rolled, cold rolled, annealed, etc.

[0020] Beneficial effects of the present invention: The aluminum alloy composite material prepared by the method of the present invention has an excellent composite interface, a uniformly distributed composite layer, and good corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a composite rate test diagram of the sample in Example A;

[0022] Figure 2 This is a composite rate test diagram of the sample of Example B;

[0023] Figure 3 This is a composite rate test diagram of the sample in Example C; DETAILED DESCRIPTION

[0024] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the scope of protection.

[0025] An aluminum alloy composite material for brazing, wherein the alloy of the core material contains 0.8 to 1.1 weight % Si, no more than 0.3 weight % Fe, 0.5 to 0.7 weight % Cu, 1.5 to 1.8 weight % Mn, no more than 0.1 weight % Ti, the content of other single elements is ≤0.05 weight %, and the balance is aluminum. The alloy of the composite layer 1 contains: 9.0 to 11.0 weight % Si, <0.3 weight % Fe, <0.15 weight % Cu, <0.1 weight % Zn, the content of other single elements is ≤0.05 weight %, and the balance is aluminum. The alloy of the composite layer 2 contains: 0.3 to 0.5 weight % Si, <0.3 weight % Fe, 3.5 to 4.5 weight % Zn, 0.9 to 1.3 weight % Ni, the content of other single elements is ≤0.05 weight %, and the balance is aluminum. The composite layer i accounts for 12% of the thickness of the composite material, and the composite layer 2 accounts for 16% of the thickness of the entire material.

[0026] The preparation method of the above aluminum alloy composite material comprises the following specific steps:

[0027] Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape;

[0028] Step 2: Saw the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product (450mm thickness);

[0029] Step 3: Take the aluminum product in step 2 and perform hot rolling to roll a thinner aluminum product (300 mm thickness), control the straightness to be less than or equal to 0.2 mm / m, and perform secondary milling, so as to keep the performance of the plate as uniform as possible;

[0030] Step 4: Take the aluminum product in step 3 as the core material and stack two layers of plates on top and bottom, perform compounding and hot rolling, roll into a hot-rolled coil (5.0 mm) of specified specifications, and continue cold rolling to reach the intermediate thickness (0.23 mm);

[0031] Step 5: annealing the coil in step 4;

[0032] Step 6: cold rolling the coil in step 5 to a final thickness (0.2 mm);

[0033] Step 7: Straighten the coiled material in step 5;

[0034] Step 8: Cut and shape the coiled material in step 7.

[0035] The product obtained above was divided into three sections, namely A, B and C, in front, middle and back, and the composite layers were tested, as shown in Table 1.

[0036] Table 1

[0037] Serial number Composite layer ratio (%) Composite layer 2 ratio (%) A 12.86 15.84 B 12.65 16.31 C 12.04 16.96

[0038] Then the composite layer distribution diagrams of the three sections of samples ABC were tested, referring to Figure 1-3 ,It can be seen that the overall material composite layer distribution of samples in sections A, B, and C is also relatively uniform.

[0039] These three materials from the same batch not only meet the performance requirements of automotive heat exchangers, but also have a relatively uniform distribution of the overall material composite layer.

[0040] According to the above test data, it can be understood that the aluminum alloy composite material prepared by the method of this embodiment has a uniform and stable distribution of the composite layer, is easy to weld, and has good corrosion resistance.

Claims

1. An aluminum alloy composite material for brazing, characterized in that: The material of the aluminum alloy composite material for brazing is a multilayer composite material, the multilayer composite material comprises a core material, a composite layer 1 and a composite layer 2, the alloy of the core material comprises (mass fraction ratio): 0.8-1.1% Si, 0.5-0.7% Cu, 1.5-1.8% Mn, <0.3% Fe, <0.1% Ti, the mass fraction of a single element is ≤0.05% and the mass fraction of other elements is ≤0.15%, and the balance is aluminum; The alloy of the composite layer 1 comprises (by mass fraction): 9.0-11.0% Si, <0.3% Fe, <0.15% Cu, <0.1% Zn, ≤0.05% of other elements, and the balance is aluminum; The alloy of the second composite layer comprises (mass fraction ratio): 0.3 to 0.5% Si, <0.3% Fe, 3.5 to 4.5% Zn, 0.9 to 1.3% Ni, ≤0.05% of other elements for a single element, and the balance is aluminum.

2. The aluminum alloy composite material for brazing according to claim 1, characterized in that: The first composite layer is located on the outer surface of the core material, and the second composite layer is located on the inner surface of the core material.

3. The aluminum alloy composite material for brazing according to claim 1 or 2, characterized in that: The thickness of the composite layer 1 and the composite layer 2 are respectively 12% and 16% of the thickness of the multi-layer composite material.

4. A method for preparing the aluminum alloy composite material for brazing according to any one of claims 1 to 3, wherein: The method comprises the following steps: Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape; Step 2: Saw the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product with a thickness of 450mm; Step 3: hot-roll the aluminum product in step 2 to produce a thinner aluminum product with a thickness of 300 mm; Step 4: Take the aluminum product in step 3 as the core material and stack two layers of plates on top and bottom, perform compounding and hot rolling, and roll the hot-rolled coil into a specified specification with a thickness of 5.0 mm, and continue cold rolling to reach an intermediate thickness of 0.23 mm; Step 5: annealing the coil in step 4; Step 6: cold rolling the coil in step 5 to a final thickness of 0.2 mm; Step 7: Straighten the coiled material in step 5; Step 8: Cut and shape the coiled material in step 7.

5. The method for preparing the aluminum alloy composite material according to claim 4, characterized in that: In step 3, the aluminum product needs to control the straightness to be less than or equal to 0.2 mm / m, and undergo secondary milling.

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