Aluminum alloy forging material for welded structural member and manufacturing method thereof

Abstract

The invention provides a welding structure component aluminium alloy forging material which maintains strength of extension, and has the characteristics of excellent welding crack performance and stress corrosion crack performance. The welding structure component aluminium alloy forging material comprises 0.4-4.0 mass% of Mg, 3.5-7.0 mass% of Zn, 0.1-0.5 mass% of Cu, and 0.3 mass%-0.8 mass% of Mn, and also comprises at least one selected from 0.001-0.15 mas% of Ti, and 0.1-0.5% of Cr, 0.05-0.25 mass% of Zr. Si is limited to be less than 0.5 mass%; Fe is limited to be less than 0.5 mass%; and the residual is formed by A1 and inevitable impurities. When a grain length in an ST direction is set to be G(ST), and a grain length in an LT direction is set to be G(LT), a formula (1) and a formula (2) or a formula (1) and a formula (3) are satisfied. 50<= G(LT)<=500...(1),(0.35* G(LT)+5)< G(ST)<= (0.35* G(LT)+85)..., G(ST)<=(0.35* G(LT)+5)...(3).

Description

technical field [0001] The invention relates to an aluminum alloy forging material suitable for welding structural components and a manufacturing method thereof. Background technique [0002] 7000-series aluminum alloys, which are high-strength and excellent in corrosion resistance, are widely used as structural members of transportation vehicles such as automobiles, motorcycles, railway vehicles, and airplanes. (Hereafter, "aluminum alloy" is described as "Al alloy".) [0003] Al alloy forgings based on 7N01, which is a representative alloy of 7000-series Al alloys, are produced through the following process: hot forging at a temperature of 350 to 500°C, followed by solution treatment at a temperature of 400 to 500°C, Thereafter, natural aging treatment is not carried out, but artificial aging treatment is carried out. [0004] However, when it is intended to use the 7000-series Al alloy as a weldable forging material, it is known that it is an alloy that is difficult to ...

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Problems solved by technology

[0010] However, in the method disclosed in Patent Document 1, the process of performing solution treatment, quenching treatment, and artificial aging treatment on the welded structure is performed to correct the strength, which is very restrictive in practical use.

[0011] In addition, in the method disclosed in Patent Document 2, only the composition of the aluminum alloy is specified, but the performance of the forged material fluctuates greatly depending on the manufacturing conditions, and the reproducibility of the performance of the forged material is poor.

[0012] In this way, the relationship between cracks during welding and factors such as composition and crystal structure has not been sufficiently verified so far.

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