6-series vehicle aluminum alloy profile with high energy absorption characteristic and preparation method of 6-series vehicle aluminum alloy profile

Abstract

The invention relates to the technical field of aluminum alloy processes, in particular to a 6-series vehicle aluminum alloy profile with a high energy absorption characteristic and a preparation method of the 6-series vehicle aluminum alloy profile with the high energy absorption characteristic. The content of Fe is 0.1 to 0.18 percent; the content of Cu is 0.02 to 0.05 percent; the content of Mn is 0.06 to 0.11 percent; the content of Mg is 0.85 to 0.92 percent; the content of Cr is 0.07 to 0.15 percent; the content of Zn is less than or equal to 0.1%; the total content of other impurity elements is less than or equal to 0.03%; the balance is Al; the content of Mg2Si in the aluminum alloy profile is 1.34%-1.45%, and the content of excess Si is smaller than or equal to 0.1%. The aluminum alloy profile has excellent mechanical properties and high energy absorption characteristics, and the safety performance of vehicle collision can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy processing, and in particular to an aluminum alloy profile with high energy absorption characteristics for 6 series vehicles and a preparation method thereof. Background Art

[0002] Aluminum alloy profiles are increasingly used in automotive safety components. They are mainly used in front and rear anti-collision beams, energy absorption boxes, door sill beams, longitudinal beams and other parts of the protection system to achieve lightweight and improve safety. Compared with steel protection systems, aluminum alloy products of the same type are lighter in weight, and in simulated collision analysis, aluminum alloys also have advantages in energy absorption. The strength of existing aluminum alloys for automotive protection systems can meet technical indicators, but the energy absorption effect is average (6000-8000J). Compared with ordinary aluminum alloy profiles, this type of aluminum alloy needs to have higher strength and better toughness to meet the energy absorption characteristics of vehicle collisions.

[0003] Therefore, there is an urgent need for an aluminum alloy profile for 6 series vehicles that has both excellent mechanical properties and high energy absorption characteristics. Summary of the invention

[0004] The present invention aims to solve the problem that the aluminum alloy profile for 6 series vehicles is difficult to have both excellent mechanical properties and high energy absorption characteristics.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a 6-series automotive aluminum alloy profile with high energy absorption characteristics, wherein the components and their weight percentages in the aluminum alloy profile are:

[0006] Si content is 0.52-0.58%;

[0007] Fe content is 0.1-0.18%;

[0008] Cu content is 0.02-0.05%;

[0009] Mn content is 0.06-0.11%;

[0010] Mg content is 0.85-0.92%;

[0011] Cr content is 0.07-0.15%;

[0012] Zn content is ≤0.1%;

[0013] The total content of other impurity elements is ≤ 0.03%;

[0014] The balance is Al;

[0015] The content of Mg2Si in the aluminum alloy profile is 1.34-1.45%, and the content of excess Si is ≤0.1%.

[0016] A second aspect of the present invention provides a method for preparing a 6-series automotive aluminum alloy profile with high energy absorption characteristics, characterized in that the preparation method comprises:

[0017] Melting, slagging, degassing and deslagging, filtering, refining, casting, homogenization, extrusion, pre-aging, aging;

[0018] In the extrusion, in the extrusion die of the extrusion equipment, a baffle is set 3-5 mm in front of the working belt, the height of the baffle is 4-5 mm, and the angle between the feed side and the baffle is 40-50 degrees.

[0019] A third aspect of the present invention provides a 6-series automotive aluminum alloy profile with high energy absorption characteristics produced by the above-mentioned preparation method.

[0020] The beneficial effects of the present invention are:

[0021] By optimizing the alloy ratio and specifying the extrusion die setting, the high energy absorption characteristic 6 series automotive aluminum alloy profile provided by the present invention has both excellent mechanical properties and high energy absorption characteristics. Furthermore, in combination with a specific extrusion process and heat treatment method, the performance of the aluminum alloy is even better. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a cross-sectional view of the aluminum alloy profile with high energy absorption characteristics for the 6 Series vehicle. DETAILED DESCRIPTION

[0023] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0024] In the present invention, the high energy absorption property is a crushing energy absorption property with a crushing score of ≥16 points in the DBL4919 standard test. In particular, the 6 series automotive aluminum alloy profile provided by the present invention has an elongation strength (R P0.2 )≥275MPa, tensile strength (R m )≥295MPa, far exceeding the standard performance requirements of GB / T 6892.

[0025] In the present invention, the heat treatment includes pre-aging treatment and aging treatment.

[0026] It is difficult for existing technologies to produce 6 series aluminum alloy profiles with both excellent mechanical properties and high energy absorption characteristics. When used in automobile manufacturing, it cannot effectively improve the safety performance of vehicle collisions.

[0027] In the present invention, the inventors found that by optimizing the alloy composition and adjusting the processing technology, the 6 series aluminum alloy can have both excellent mechanical properties and high energy absorption characteristics.

[0028] To achieve this goal, the inventors tried to optimize the composition and processing technology of each component of the 6 series aluminum alloy. The inventors found that the above purpose can be achieved by optimizing the alloy ratio and specific extrusion die setting limitations. Furthermore, specific extrusion processes and heat treatment methods make the performance of aluminum alloys even better.

[0029] The first aspect of the present invention provides a 6-series automotive aluminum alloy profile with high energy absorption characteristics, wherein the components and their weight percentages in the aluminum alloy profile are:

[0030] Si content is 0.52-0.58%;

[0031] Fe content is 0.1-0.18%;

[0032] Cu content is 0.02-0.05%;

[0033] Mn content is 0.06-0.11%;

[0034] Mg content is 0.85-0.92%;

[0035] Cr content is 0.07-0.15%;

[0036] Zn content is ≤0.1%;

[0037] The total content of other impurity elements is ≤ 0.03%;

[0038] The balance is Al;

[0039] The content of Mg2Si in the aluminum alloy profile is 1.34-1.45%, and the content of excess Si is ≤0.1%.

[0040] In the present invention, the inventors have found that the above-mentioned component design can improve the toughness of the metal to the maximum extent while ensuring that the product has excellent mechanical properties. In the present invention, the toughness is reflected in excellent energy absorption characteristics.

[0041] A second aspect of the present invention provides a method for preparing a 6-series automotive aluminum alloy profile with high energy absorption characteristics, characterized in that the preparation method comprises:

[0042] Melting, slagging, degassing and deslagging, filtering, refining, casting, homogenization, extrusion, pre-aging, aging;

[0043] In the extrusion, in the extrusion die of the extrusion equipment, a baffle is set 3-5 mm in front of the working belt, the height of the baffle is 4-5 mm, and the angle between the feed side and the baffle is 40-50 degrees.

[0044] In the extrusion die of the extruder, the baffle is a trapezoidal protrusion with an angle of 40-50° on the inner wall of the die welding cavity. It is located in the die welding chamber and close to the die working belt outlet.

[0045] In the present invention, the inventors have found through experiments that the friction of the aluminum alloy in the mold is increased by using a die with a baffle, the deformation of the aluminum alloy is increased, and the degree of grain crushing is increased, thereby obtaining finer grains. The average grain size of the aluminum alloy profile is 90-110μm, and the average grain size of the aluminum alloy profile is 110-130μm when the die is extruded without a baffle, and the average grain size is reduced by about 20%. The finer aluminum alloy grain structure will comprehensively improve the performance of the aluminum alloy, including mechanical properties, corrosion resistance, toughness and energy absorption characteristics.

[0046] In the present invention, the angle between the feed side and the baffle is 40-50 degrees, so that the aluminum alloy flows smoothly in the mold welding chamber. There is a sloped trapezoidal protrusion on the inner wall near the working belt outlet to block the smooth flow of the aluminum alloy and increase the resistance.

[0047] According to the present invention, the extrusion conditions include: extrusion breakthrough pressure of 26-28 MPa, cast rod length of 700-800 mm, cast rod heating temperature of 455-475° C., and extrusion speed of 4.5-5.5 m / min.

[0048] In the present invention, the above-mentioned specific low-temperature and medium-speed extrusion process can further optimize the grain size of the aluminum alloy profile. High temperature will increase the ability of the aluminum alloy recrystallization process and accelerate grain growth. Therefore, the use of a low-temperature extrusion process can inhibit the grain growth process and optimize the grain size of the aluminum alloy profile.

[0049] According to the present invention, the conditions of the pre-aging treatment include: (130-140)°C×(35-45)min, and the pre-aging treatment is completed within 12 hours after the extrusion is completed.

[0050] In the present invention, the above-mentioned pre-aging treatment can eliminate the performance fluctuations of the aluminum alloy profiles caused by natural aging, which is beneficial to the later processing. The pre-aging process will increase the number of stable cores of the transition phase β′ (Mg2Si) in the matrix and make them dispersed, reduce the impact of the natural aging process on the product, slow down the growth rate of the mechanical properties of the product in the T4 state, so that the product has better processing performance.

[0051] According to the present invention, the conditions of the aging treatment include: (210-215)°C×(5-6)h.

[0052] In the present invention, the above-mentioned aging treatment can improve the energy absorption effect of the product.

[0053] In the present invention, the pre-aging heat treatment is completed before processing, and the heat treatment is performed after processing. The processing is machining of aluminum profiles, including bending, stamping, punching, cutting, welding, etc.

[0054] According to the present invention, the extrusion conditions also include: a quenching temperature of 500-540°C and a quenching cooling rate of 30-55°C / s.

[0055] In the present invention, the specific quenching cooling rate can control the flatness of the aluminum alloy profile within the range of <3mm / m. This method can ensure high-strength quenching while taking into account the cold deformation of the aluminum alloy profile, improve the shape and position dimensional accuracy, and reduce the scrap rate. In contrast, when using the water mist quenching method, the quenching cooling rate is generally 21℃ / s, and the flatness of the aluminum alloy profile can reach <2.5mm / m, but the cooling intensity cannot meet the performance requirements of the aluminum alloy profile; and when using the water tank immersion cooling method, the quenching cooling rate is generally 68℃ / s. Although it can meet the performance requirements of the aluminum alloy profile, the dimensional tolerance flatness of the aluminum alloy profile is only 3-5mm / m, the deformation is large, and it cannot meet the shape and position dimensional requirements.

[0056] In the present invention, there is no particular limitation on the smelting, degassing and slag removal, refinement, casting and homogenization treatment, and the conventional smelting, degassing and slag removal, refinement, casting and homogenization treatment process of 6 series aluminum alloy can be used.

[0057] A third aspect of the present invention provides a 6-series automotive aluminum alloy profile with high energy absorption characteristics produced by the above-mentioned preparation method.

[0058] Test Method

[0059] The test method for aluminum alloy profile composition is in accordance with GB / T7999-2015 aluminum and aluminum alloy photoelectric direct reading emission spectrum analysis method, and the test equipment is ARL-3460 direct reading spectrometer.

[0060] The mechanical properties test method is in accordance with GB / T16865-2013 Specimens and methods for tensile testing of deformed aluminum, magnesium and their alloy products, and the test equipment is AG-X 100KN electronic universal testing machine.

[0061] The crush energy absorption characteristics test method is in accordance with the DBL4919 crush scoring standard, and the test equipment is AG-X 100KN electronic universal testing machine.

[0062] The high-magnification grain size test method is in accordance with GB / T3246.1-2012 Deformed aluminum and aluminum alloy product organization inspection method Part 1: Microstructure inspection method, test equipment: AXIO universal research-grade inverted material microscope.

[0063] The technical scheme of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described herein are only some embodiments of the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments implemented by ordinary technicians in this field without making creative improvements belong to the protection scope of the present invention.

[0064] Example 1

[0065] A. Melting: Prepare aluminum alloy raw materials according to the following weight ratios: Si: 0.55%; Fe: 0.13%; Cu: 0.03%; Mn: 0.06%; Mg: 0.87%; Cr: 0.09%; Zn: 0.01%; the total content of other impurity elements is ≤ 0.03%; the content of the balance Al, Mg2Si is 1.37%, the content of excess Si is 0.048%, and the smelting process is carried out according to conventional smelting operations;

[0066] B. Casting: The casting process is carried out according to conventional casting operations;

[0067] C. Homogenization treatment: After casting, the ingot is homogenized, and the homogenization process parameters are set to: 570℃×5h;

[0068] D. Extrusion: Add a baffle at 3.5mm from the front end of the working belt. The baffle is 4.5mm high. The angle between the feed side and the baffle is 45 degrees. The length of the cast rod is 780mm, the diameter of the cast rod is 310mm, the heating temperature of the cast rod is 470℃, the mold temperature is 510℃, the extrusion barrel temperature is 440℃, the extrusion breakthrough pressure is 27MPa, the extrusion speed is 5m / min, the quenching temperature is 510℃, and the quenching cooling rate is 45℃ / s.

[0069] E. Pre-aging treatment: It should be carried out within 12 hours after extrusion, and the pre-aging system is 135℃×40min;

[0070] F. Aging treatment: The aging system is 213℃×5.5h.

[0071] An aluminum alloy profile A1 was obtained.

[0072] Example 2

[0073] An aluminum alloy profile is prepared according to the preparation method of Example 1, except that the aluminum alloy components are Si: 0.52%; Fe: 0.1%; Cu: 0.02%; Mn: 0.06%; Mg: 0.85%; Cr: 0.07%; Zn: 0.05%, the content of Mg2Si is 1.34%, and the content of excess Si is 0.029%.

[0074] An aluminum alloy profile A2 is obtained.

[0075] Example 3

[0076] An aluminum alloy profile is prepared according to the preparation method of Example 1, except that the aluminum alloy components are Si: 0.58%; Fe: 0.18%; Cu: 0.05%; Mn: 0.06%; Mg: 0.85%; Cr: 0.07%; Zn: 0.05%, the Mg2Si content is 1.34%, and the excess Si content is 0.089%.

[0077] Aluminum alloy profile A3 is obtained.

[0078] Example 4

[0079] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that a baffle was added 5 mm from the front end of the working belt, the baffle was 5 mm high, and the angle between the feed side and the baffle was 50 degrees.

[0080] Aluminum alloy profile A4 is obtained.

[0081] Example 5

[0082] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that a baffle was added 3 mm from the front end of the working belt, the baffle was 4 mm high, and the angle between the feed side and the baffle was 40 degrees.

[0083] Aluminum alloy profile A5 was obtained.

[0084] Example 6

[0085] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the extrusion breakthrough pressure was 26 MPa, the casting rod heating temperature was 455° C., and the extrusion speed was 4.5 m / min.

[0086] Aluminum alloy profile A6 was obtained.

[0087] Example 7

[0088] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the extrusion breakthrough pressure was 28 MPa, the casting rod heating temperature was 475° C., and the extrusion speed was 5.5 m / min.

[0089] Aluminum alloy profile A7 was obtained.

[0090] Example 8

[0091] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the pre-aging treatment was 140° C.×45 min and the aging system was 215° C.×6 h.

[0092] Aluminum alloy profile A8 was obtained.

[0093] Example 9

[0094] The aluminum alloy profile was prepared according to the preparation method of Example 1, except that the pre-aging treatment was 130° C.×35 min and the aging system was 210° C.×5 h.

[0095] Aluminum alloy profile A9 was obtained.

[0096] Comparative Example 1

[0097] An aluminum alloy profile is prepared according to the method of Example 1, except that the components of the aluminum alloy are Si: 0.62%; Fe: 0.06%; Cu: 0.01%; Mn: 0.05%; Mg: 0.65%; Cr: 0.02%; Zn: 0.02%, the content of Mg2Si is 1.00%, and the content of excess Si is 0.245%.

[0098] An aluminum alloy profile DA1 was obtained.

[0099] Comparative Example 2

[0100] The aluminum alloy profile is prepared according to the method of Example 1, except that a common extrusion die without a baffle is used.

[0101] Aluminum alloy profile DA2 was obtained.

[0102] Comparative Example 3

[0103] The aluminum alloy profile was prepared according to the method of Example 1, except that the extrusion breakthrough pressure was 25.5 MPa, the casting heating temperature was 510° C., and the extrusion speed was 6.5 m / min.

[0104] Aluminum alloy profile DA3 was obtained.

[0105] Comparative Example 4

[0106] The aluminum alloy profile is prepared according to the method of Example 1, except that the quenching cooling rate is 68° C. / s.

[0107] Aluminum alloy profile DA4 was obtained.

[0108] Comparative Example 5

[0109] The aluminum alloy profile was prepared according to the method of Example 1, except that the pre-aging treatment was 165°C × 1h and the aging system was 175°C × 8h

[0110] Aluminum alloy profile DA5 was obtained.

[0111] The performance of A1-A9 and DA1-DA5 is tested as shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115]

[0116] By comparing the embodiments with the comparative examples, it can be seen that the aluminum alloy profiles provided by the present invention have both excellent mechanical properties and high energy absorption characteristics. Specifically, the mechanical properties of comparative example 1 are slightly lower. The reason for the poor energy absorption characteristics is that the content of Mg2Si strengthening phase in the alloy ratio is relatively low, resulting in low performance, and other grain refining elements are relatively small, resulting in a larger average grain size of the product, resulting in poor energy absorption characteristics. The reason for the poor energy absorption characteristics of comparative example 2 is that ordinary mold extrusion is used, and there is no grain refining effect of the baffle, which makes the product grain size larger and the energy absorption effect is reduced.

[0117] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A 6-series automotive aluminum alloy profile with high energy absorption characteristics, characterized in that: The components and their weight percentages in the aluminum alloy profile are: Si content is 0.52-0.58%; Fe content is 0.1-0.18%; Cu content is 0.02-0.05%; Mn content is 0.06-0.11%; Mg content is 0.85-0.92%; Cr content is 0.07-0.15%; Zn content is ≤0.1%; The total content of other impurity elements is ≤ 0.03%; The balance is Al; The content of Mg2Si in the aluminum alloy profile is 1.34-1.45%, and the content of excess Si is ≤0.1%.

2. A method for preparing the 6-series automotive aluminum alloy profile with high energy absorption characteristics as claimed in claim 1, characterized in that: The preparation method comprises: Melting, degassing and slag removal, filtering, refining, casting, homogenization, extrusion, pre-aging treatment, aging treatment; In the extrusion, in the extrusion die of the extrusion equipment, a baffle is set 3-5 mm in front of the working belt, the height of the baffle is 4-5 mm, and the angle between the feed side and the baffle is 40-50 degrees.

3. The preparation method according to claim 2, characterized in that: The extrusion conditions include: extrusion breakthrough pressure of 26-28 MPa, cast rod length of 700-800 mm, cast rod heating temperature of 455-475° C., and extrusion speed of 4.5-5.5 m / min.

4. The preparation method according to claim 2, characterized in that: The pre-aging treatment conditions include: (130-140)°C×(35-45)min, and is carried out within 12 hours after extrusion is completed.

5. The preparation method according to claim 2, characterized in that: The aging treatment conditions include: (210-215)°C×(5-6)h.

6. The preparation method according to claim 2, characterized in that: The extrusion conditions also include: a quenching temperature of 500-540° C. and a quenching cooling rate of 30-55° C. / s.

7. A 6 series automotive aluminum alloy profile with high energy absorption characteristics obtained by the preparation method described in any one of claims 2 to 6.

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