High-performance aluminum alloy profile for left and right side wall thresholds of automobile and preparation method of high-performance aluminum alloy profile

Abstract

The invention discloses a high-performance aluminum alloy profile for left and right side wall thresholds of an automobile and a preparation method of the high-performance aluminum alloy profile, and belongs to the technical field of aluminum alloy preparation. The invention relates to a high-performance aluminum alloy profile for automobile left and right side wall thresholds. The high-performance aluminum alloy profile comprises the following metal element components in percentage by mass: 0.88-1.1% of Si, 0.65-0.8% of Mg, less than or equal to 0.05% of Cu, 0.45-0.55% of Mn, less than or equal to 0.05% of Cr, less than or equal to 0.13% of Fe, less than or equal to 0.04% of Ti, less than or equal to 0.1% of Zn and the balance of Al and inevitable impurities. In the preparation process, after extrusion, online water mist quenching is adopted, and the aging system that the aging temperature ranges from 190 DEG C to 200 DEG C and the aging time ranges from 4 h to 4.5 h is adopted. Alloy components are matched with a preparation process, and the aluminum alloy profile suitable for the left and right side wall thresholds of the automobile with the strength and plasticity meeting the requirements is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy profiles, and in particular to a high-performance aluminum alloy profile for left and right side sills of an automobile and a preparation method thereof. Background Art

[0002] The development trend of automobiles is lightweight, safe, reliable, comfortable, and low fuel consumption. Lightweighting of automobiles is to reduce the weight of the automobile body as much as possible, improve the power of the automobile, reduce energy consumption, and reduce emissions under the premise of ensuring the strength and safety of the automobile. At present, aluminum alloy has become the main material for automobile manufacturing for lightweight automobiles. In the automobile body structure, the side sill beam of the automobile not only needs to withstand the strength of stepping on, but also needs to transmit and absorb external impact force through its own elastic-plastic deformation to protect the safety of passengers during the collision of the automobile. However, due to the high brittleness and easy breakage of aluminum alloy materials themselves, they cannot meet the use requirements of automobile sill beams. Therefore, it is urgent to study a high-performance aluminum alloy profile to meet the use requirements of automobile side sill beams and ensure the safety of automobile structures. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a high-performance aluminum alloy profile for automobile left and right side sills and a preparation method thereof, and combines the alloy composition with the preparation process to obtain an aluminum alloy profile suitable for automobile left and right side sills with strength and plasticity that meet the requirements.

[0004] The technical solution adopted by the present invention is: A high-performance aluminum alloy profile for left and right side sills of an automobile comprises the following metal element components in mass percentage: Si 0.88-1.1%, Mg 0.65-0.8%, Cu≤0.05%, Mn 0.45-0.55%, Cr≤0.05%, Fe≤0.13%, Ti≤0.04%, Zn≤0.1%, and the balance is Al and unavoidable impurities.

[0005] Furthermore, the aluminum alloy profile has a tensile strength of ≥305 MPa, a yield strength of 285-320 MPa, and an elongation of ≥10%.

[0006] Furthermore, the present invention comprises the following elemental components in mass percentage: Si 0.9-1.0%, Mg 0.70-0.75%, Cu 0.028-0.035%, Mn 0.50-0.51%, Cr≤0.04%, Fe≤0.05%, Ti≤0.03%, Zn≤0.02%, and the balance is Al and unavoidable impurities.

[0007] Furthermore, the aluminum alloy profile has a tensile strength of ≥305 MPa, a yield strength of 295-310 MPa, and an elongation of ≥10%.

[0008] A preparation method of a high-performance aluminum alloy profile for left and right side sills of an automobile comprises the following steps: batch feeding and melting according to alloy composition → casting aluminum rods → homogenization treatment → extrusion molding → online quenching → stretching → sawing → artificial aging → mechanical property testing to see if it meets the requirements.

[0009] Furthermore, in the batch feeding smelting process, the purity of each added metal element is ≥98%, and the interval time for each addition of metal elements in the batch feeding process is at least 10 minutes; and when adding Si and Mn elements, the metal Si and Mn are first melted in a crucible respectively, and then added to the smelting furnace.

[0010] Furthermore, the homogenization process is as follows: the homogenization temperature is 590-600° C., the heat preservation time is 8-12 hours, and air cooling to room temperature is performed after the homogenization is completed.

[0011] Furthermore, the extrusion molding process is specifically as follows: the aluminum rod is extruded after being peeled, the extrusion barrel temperature is 440±20°C, the mold temperature is 480±15°C, the mold heating time is 5~24h, the aluminum rod temperature is 510±15°C, the extrusion rod speed is 1.0~1.5mm / s, and the outlet temperature is 520~540°C.

[0012] Furthermore, in the online quenching process, 60% water mist is used for online quenching, and the temperature after quenching is ≤50°C.

[0013] Furthermore, in the artificial aging process, the aging temperature is 190-200° C., and the aging time is 4-4.5 hours.

[0014] The beneficial effects of the present invention are: The present invention provides a high-performance aluminum alloy profile for automobile left and right side sills and a preparation method thereof. By reasonably adjusting the contents of main alloying elements Mg, Si, Mn and trace elements in 6XXX series aluminum alloys and controlling the quenching method and aging system, it is ensured that the aluminum alloy profile has high strength and meets the mechanical property requirements of the automobile left and right side sills. DETAILED DESCRIPTION

[0015] The present invention provides a high-performance aluminum alloy profile for left and right side sills of an automobile and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] A high-performance aluminum alloy profile for left and right side sills of an automobile comprises the following metal element components in mass percentage: Si 0.88-1.1%, Mg 0.65-0.8%, Cu≤0.05%, Mn 0.45-0.55%, Cr≤0.05%, Fe≤0.13%, Ti≤0.04%, Zn≤0.1%, and the balance is Al and inevitable impurities; preferably, each element component is: Si 0.9-1.0%, Mg 0.70-0.75%, Cu 0.028-0.035%, Mn 0.50-0.51%, Cr≤0.04%, Fe≤0.05%, Ti≤0.03%, Zn≤0.02%, and the balance is Al and inevitable impurities.

[0017] In this embodiment, by limiting and optimizing the chemical composition of the aluminum alloy profiles for the left and right side sills of the automobile, the Si, Mg and Mn elements are mainly optimized, and Si is limited to 0.88-1.1%, Mg to 0.65-0.8%, and Mn to 0.45-0.55%. More preferably, Si is limited to 0.9-1.0%, Mg to 0.70-0.75%, and Mn to 0.50-0.51%. Among them, Mg and Si are mainly used to form the strengthening phase Mg2Si, and promote strengthening through an appropriate amount of excess Si; adding a high content of Mn to the 6 series aluminum alloy can form a large amount of thermally stable AlMnFeSi dispersed phase. At the same time, in addition to binding the free Si to the second phase particles, Mn can also hinder the occurrence of recrystallization by forming a dispersed phase, making the plasticity of the profile better, thereby significantly improving the mechanical properties of the alloy at high temperatures. Moreover, after T6 aging treatment, there are a large number of needle-shaped pre-β" phases and disc-shaped Q' phases in the microstructure of the Al-Mg-Si-Cu alloy with a high Mn content, and there is also a strengthening effect of the Mn-containing phase, which can ultimately increase the tensile strength by 50% to 60%, and the mechanical properties of the alloy are greatly improved.

[0018] The preparation method of the high-performance aluminum alloy profile for the left and right side sills of the above-mentioned automobile includes the following steps: batch feeding and melting according to the alloy composition → casting aluminum rods → homogenization treatment → extrusion molding → online quenching → stretching → sawing → artificial aging → mechanical property testing to see if it meets the requirements.

[0019] Among them, in the batch feeding smelting process, the purity of each added metal element is ≥98%, and the interval time of each addition of metal elements in the batch feeding process is at least 10 minutes; and when adding Si and Mn elements, the metal Si and Mn are first melted in the crucible separately, and then added into the smelting furnace.

[0020] In the homogenization process, the homogenization temperature is 590-600°C, the heat preservation time is 8-12h, and after the homogenization is completed, it is air-cooled to room temperature.

[0021] In the extrusion molding process, the aluminum rod is peeled and then extruded. The temperature of the extrusion barrel is 440±20℃, the mold temperature is 480±15℃, the mold heating time is 5~24h, the aluminum rod temperature is 510±15℃, the extrusion rod speed is 1.0~1.5mm / s, and the outlet temperature is 520~540℃.

[0022] In the online quenching process, 60% water mist is used for online quenching, and the temperature after quenching is ≤50℃.

[0023] In the artificial aging process, the aging temperature is 190~200℃ and the aging time is 4~4.5h.

[0024] The above-mentioned online quenching and artificial aging system are combined to achieve the control of the performance of aluminum alloy profiles. The online quenching and artificial aging of aluminum alloy profiles are both heat treatment processes for aluminum processing. The purpose of online quenching is to obtain a supersaturated solid solution, and the purpose of aging is to obtain a dispersed strengthening phase. In the present invention, the extrusion outlet is controlled to reach 520~540℃, so that the Mg2Si strengthening phase is basically completely dissolved, and then quenched online by 60% water mist, and the temperature after quenching is ≤50℃, so that it can be quickly cooled to prevent the precipitation of the Mg2Si strengthening phase, that is, the alloy elements are retained in the supersaturated solid solution; on the basis of the above-mentioned relatively high degree of solid solution, high-temperature artificial aging is used to dissolve alloy elements such as Mg and Si to form a dispersed Mg2Si precipitation phase. Under this aging system, it can be ensured that the obtained precipitation phase is large in number, small in size and dispersed, thereby ensuring the high strength of the aluminum alloy profile. If the time is too short, the precipitation phase will not be completely precipitated, and if the time is too long, the precipitation phase will grow, which will lead to reduced performance. In addition, under the premise that the solid solution degree of the present invention is relatively high, if the aging temperature is low, the aging time needs to be increased, resulting in high energy consumption and low efficiency. Moreover, at a lower aging temperature, the precipitation phase will not be completely precipitated, and as the aging time increases, the precipitation phase will also grow to a certain extent, making it difficult to achieve the high strength required by the present invention.

[0025] Example

[0026] The present embodiments 1-9 provide a high-performance aluminum alloy profile for left and right side sills of an automobile, wherein the elemental components of the aluminum alloy profiles of embodiments 1-9 are as shown in Table 1.

[0027] Table 1 Element composition of aluminum alloy profiles

[0028] The high-performance aluminum alloy profiles for the left and right side sills of the automobile of the above-mentioned embodiments 1-9 are prepared according to the following process: batch feeding and melting according to the alloy composition → casting aluminum rods → homogenization treatment → extrusion molding → online quenching → stretching → sawing → artificial aging → testing whether the mechanical properties meet the requirements.

[0029] Specifically, in the above-mentioned feeding and smelting process, batch feeding is adopted, the purity of each added metal element is ≥98%, and the interval time of each addition of metal elements in the batch feeding process is at least 10 minutes; and when adding Si and Mn elements, the metal Si and Mn are first melted in a crucible respectively, and then added to the smelting furnace, which can minimize the situation of sinking to the bottom due to insufficient dissolution, and can quickly mix with Al elements and the like.

[0030] In the above homogenization process, the homogenization temperature is 595° C., the heat preservation time is 10 h, and after the homogenization is completed, the mixture is air-cooled to room temperature.

[0031] In the above extrusion molding process, the aluminum rod is extruded after being peeled, the extrusion barrel temperature is 440°C, the mold temperature is 480°C, the mold heating time is 5h, the aluminum rod temperature is 510°C, the extrusion rod speed is 1.0mm / s, and the outlet temperature is 530-540°C.

[0032] In the above-mentioned online quenching process, 60% water mist is used for online quenching, which can effectively avoid deformation of the profile, and the temperature after quenching is ≤50°C.

[0033] In the artificial aging process, the aging temperature is 195±5°C and the aging time is 4 hours. In addition, the artificial aging needs to be performed within 1 to 10 hours after extrusion molding, preferably within 1 to 5 hours. Specifically, in the present embodiment 1-10, it is performed within 1 hour after extrusion molding.

[0034] Comparative Example 1

[0035] The difference between this comparative example and Example 1 is that in this comparative example, the element components are: Si 0.7%, Mg 0.4%, Mn 0.4%, Cu 0.1%, Cr 0.05%, Fe 0.5%, Ti 0.2%, Zn 0.2%, and the balance is Al and unavoidable impurities.

[0036] Comparative Example 2

[0037] The difference between this comparative example and Example 1 is that in this comparative example, the element components are: Si 1.3%, Mg 0.8%, Mn 0.8%, Cu 0.1%, Cr 0.05%, Fe 0.5%, Ti 0.2%, Zn 0.2%, and the balance is Al and unavoidable impurities.

[0038] The aluminum alloy profiles prepared in the above-mentioned Examples 1-9, Comparative Example 1 and Comparative Example 2 were sampled and subjected to mechanical property testing in an aging furnace, as shown in Table 2.

[0039] Table 2 Mechanical properties test results

[0040] Comparative Example 3

[0041] The difference between this comparative example and Example 8 is that the samples of this comparative example are aged in an aging furnace according to the following system, and their mechanical properties are tested, specifically: A: The aging temperature is 175±5°C, and the aging time is 4h. The yield strength of the sample under this aging system is 269MPa, which is much lower than the yield strength under the aging system of this embodiment. B: The aging temperature is 175±5°C and the aging time is 8h. The yield strength of the sample under this aging system is 290MPa. Although it can reach a relatively high yield strength, it is still lower than the yield strength under the aging system of this embodiment. In addition, this aging system has a long aging time, high energy consumption, and low production efficiency. C: The aging temperature is 210±5°C, and the aging time is 4h. The yield strength of the sample under this aging system is 265MPa, which is much lower than the yield strength under the aging system of this embodiment. Moreover, over-aging is likely to occur at this aging temperature.

[0042] It should be noted that some parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0043] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A high-performance aluminum alloy profile for left and right side sills of a car, characterized in that: The invention comprises the following metal element components in mass percentage: Si 0.88-1.1%, Mg 0.65-0.8%, Cu≤0.05%, Mn 0.45-0.55%, Cr≤0.05%, Fe≤0.13%, Ti≤0.04%, Zn≤0.1%, and the balance is Al and unavoidable impurities.

2. The high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 1, characterized in that: The aluminum alloy profile has a tensile strength of ≥305 MPa, a yield strength of 285-320 MPa, and an elongation of ≥10%.

3. The high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 1, characterized in that: The invention comprises the following element components in mass percentage: Si 0.9-1.0%, Mg 0.70-0.75%, Cu 0.028-0.035%, Mn 0.50-0.51%, Cr≤0.04%, Fe≤0.05%, Ti≤0.03%, Zn≤0.02%, and the balance is Al and unavoidable impurities.

4. A high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 2, characterized in that: The aluminum alloy profile has a tensile strength of ≥305 MPa, a yield strength of 295-310 MPa, and an elongation of ≥10%.

5. A method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile as claimed in any one of claims 1 to 4, characterized in that: The process includes: melting and casting in batches according to alloy composition → casting aluminum bars → homogenization → extrusion molding → online quenching → stretching → sawing → artificial aging → mechanical property testing to see if it meets the requirements.

6. The method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 5, characterized in that: In the batch feeding smelting process, the purity of each added metal element is ≥98%, and the interval time of each addition of metal elements in the batch feeding process is at least 10 minutes; and when adding Si and Mn elements, the metal Si and Mn are first melted in a crucible respectively, and then added into the smelting furnace.

7. The method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 5, characterized in that: The homogenization process is as follows: the homogenization temperature is 590-600° C., the heat preservation time is 8-12 hours, and air cooling to room temperature is performed after the homogenization is completed.

8. The method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 5, characterized in that: The extrusion molding process is specifically as follows: the aluminum rod is extruded after being peeled, the extrusion barrel temperature is 440±20°C, the mold temperature is 480±15°C, the mold heating time is 5~24h, the aluminum rod temperature is 510±15°C, the extrusion rod speed is 1.0~1.5mm / s, and the outlet temperature is 520~540°C.

9. The method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 5, characterized in that: In the online quenching process, 60% water mist is used for online quenching, and the temperature after quenching is ≤50°C.

10. The method for preparing a high-performance aluminum alloy profile for left and right side sills of an automobile according to claim 5, characterized in that: In the artificial aging process, the aging temperature is 190-200° C., and the aging time is 4-4.5 hours.

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