Patent ID: 7736451

Claim:
A method of manufacturing an aluminum alloy of high strength, comprising the steps of: forming a pipe material by extruding a precipitation-hardening aluminum alloy of high hardness; performing a solution treatment upon the pipe material by heating the pipe material to a temperature within a first range; naturally aging the solution treated pipe material at room temperature; performing a reversion treatment upon the naturally-aged pipe material by heating the pipe material at a temperature within the range of 150° C.-250° C., the reversion treatment being performed by a first spinning work treatment in which a roller is pressed on an outer periphery of the pipe material while the pipe material is rotated; performing a second spinning work treatment as one of plastic working upon the reversion-treated pipe material by pressing the roller on the outer periphery of the pipe material while the pipe material is rotated; and artificially aging the second spinning-work treated pipe material by heating the pipe material to a temperature within a second range lower than the first range.