| 摘要 |
PURPOSE:To obtain an Al alloy member excellent in strength in a base metal and in a weld zone, by subjecting plural pieces of Al-Zn-Mg alloys to solution heat treatment, to hardening, and then to electron beam welding to assemble the above into the shape of a product and by applying ageing to the above under proper conditions. CONSTITUTION:Two or more Al-Zn-Mg alloy forged members are subjected to solution heat treatment and water quenching, which are then subjected to electron beam welding excellent in joint efficiency to undergo assembly into the shape of a product. The above Al alloy member formed into the shape of a product is then aged at 100-150 deg.C for 10-30hr. In the above method, when ageing treatment is exerted before above-mentioned electron beam welding, additional ageing at 100-150 deg.C for 5-20hr of the alloy member after assembly is enough. By the above heat treatment method of Al alloy, forged products assembled by welding having a tensile strength of >=about 40kgf/mm<2> can be obtained.
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