Patent ID: 7713363

Claim:
A method of manufacturing a high-strength aluminum alloy extruded product excelling in corrosion resistance and stress corrosion cracking resistance, the method comprising continuously extruding a billet of an aluminum alloy comprising, hereinafter, all compositional percentages are by weight, 0.5% to 1.5% of Si, 0.9% to 1.6% of Mg, 1.7% to 2.5% of Cu, while satisfying the following equations (1), (2), (3), and (4), 3≦Si%+Mg%+Cu%≦4 (1) Mg%≦1.7×Si% (2) Mg%+Si%≦2.7 (3) Cu%/2≦Mg%≦(Cu%/2)+0.6 (4) and further comprising 0.5% to 1.2% of Mn, with the balance being Al and unavoidable impurities, into a solid product by using a solid die having a bearing length (L) of 0.5 mm or more and the bearing length (L) and thickness (T) of the solid product to be extruded have a relationship defined by L≦5T, to obtain the solid product in which a fibrous structure accounts for 60% or more in area-fraction of the cross sectional structure of the solid product, wherein a flow guide is provided in front of the solid die, an inner circumferential surface of a guide hole of the flow guide being separated from an outer circumferential surface of an orifice which is continuous with the bearing of the solid die at a distance of 5-15 mm, and the thickness of the flow guide being 5% to 25% of the diameter of the billet.