High-strength weldable aluminum alloy for vehicle bodies and preparation method thereof

Abstract

The invention relates to the technical field of non-ferrous metals, in particular to a high-strength weldable aluminum alloy for vehicle bodies and a preparation method thereof. The alloy comprises: 4.8-6.6wt.% of Zn, 1.0-2.0wt.% of Mg, 0.08-0.16wt.% of Zr, 0.03-0.06wt.% of Sc, 0.01-0.03wt.% of Ti, less than 0.15wt.% of Fe, less than 0.15wt.% of other unavoidable impurity elements, each of which is not less than 0.05wt.%, and the balance Al. The preparation method consists of: subjecting a cast ingot obtained by semicontinuous casting to uniform annealing at 200-220DEG C for 2h, then conducting furnace heating to 470-480DEG C and performing thermal insulation for 8h, then conducting hot extrusion and online water-crossing quenching, then performing heat preservation at 480-490DEG C for 1-3h, and conducting solution treatment, performing water quenching, then carrying out heat preservation at 130-160DEG C for 12-24h and conducting aging treatment. By adding elements Zr, SC and Ti, a lot of Al3Zr(Sc, Ti) dispersed phase is generated in the alloy to play a role of inhibiting recrystallized grains from nucleating and growing and obstructing dislocation migration, thereby obtaining excellent strength and toughness. The high-strength weldable aluminum alloy can be suitable for production of high-strength light structural parts for vehicle bodies.

Description

technical field [0001] The invention relates to the technical field of nonferrous metals, and discloses a high-strength weldable aluminum alloy for a vehicle body and a preparation method thereof. Background technique [0002] With the continuous improvement of automobile lightweight requirements, research on aluminum alloy materials for rail vehicles, automobiles and other car bodies has achieved certain results at home and abroad, but research on the preparation of high-strength weldable aluminum , is still blank. [0003] At present, 7005, 7N01, and 6005 aluminum alloys have been developed abroad for rail train body profiles. The above-mentioned alloys have good deformability and weldability, but the above-mentioned alloys are prone to recrystallization during the extrusion process, which leads to a decrease in the strength of the alloy. lower. [0004] High-strength Al-Zn-Mg-Cu alloys, such as 7075 and 7050 aluminum alloys, can meet the needs of structural materials fo...

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Problems solved by technology

[0002] With the continuous improvement of automobile lightweight requirements, research on aluminum alloy materials for rail vehicles, automobiles and other car bodies has achieved certain results at home and abroad, but research on the preparation of high-strength weldable aluminum , still blank

[0003] At present, 7005, 7N01, and 6005 aluminum alloys have been developed abroad for rail train body profiles. The above-mentioned alloys have good deformability and weldability, but the above-mentioned alloys are prone to recrystallization during the extrusion process, which leads to a decrease in the strength of the alloy. lower

[0004] High-strength Al-Zn-Mg-Cu alloys, such as 7075 and 7050 aluminum alloys, can meet the needs of structural materials for car bodies, but their application in the field of aluminum alloys for car bodies is limited due to their poor weldability

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