ALUMINUM ALLOY FOR EXTRUDED MATERIAL, EXTRUDED MATERIAL USING SAME, AND EXTRUDED MATERIAL PRODUCTION METHOD

摘要

The purpose of the present invention is to provide: a high strength aluminum alloy extruded material of excellent toughness and stress corrosion cracking resistance as well as high extrudability; an aluminum alloy for an extruded material that is suitable therefor; and an extruded material production method. This aluminum alloy for an extruded material is characterized: in being made, in mass%, of 6.0–7.0% of a Zn component, 1.0–1.6% of a Mg component, 0.15–0.23% of a Zr component, 0.001–0.05% of a Ti component, 0.5% or less of a Cu component, 0.5% or less of an Mn component, 0.02% or less of a Cr component, 0.20% or less of an Fe component, 0.10% or less of an Si component, the balance being made of Al and unavoidable impurities; and in the average crystal grain diameter of the billet cast structure being 250 µm or less.