Patent ID: 11512376

Abstract:
When a T1-tempered aluminum alloy extrusion is subjected to plastic working and thus formed into a product, crack occurrence is prevented during plastic working, and tensile residual stress of the product is reduced to improve stress corrosion cracking resistance. A T1-tempered 7000-series aluminum alloy extrusion is heated to a temperature range of 150° C. or higher, and then subjected to plastic working within the temperature range, and then cooled, and then subjected to artificial temper aging. An integral value (F140) of (T(t)−140)2 is controlled to 5×105 (° C.2·s) or less in a section of t1≤t≤t2, where t is time (s) from heating start, T(t) is temperature (° C.) of the extrusion at time t, t1 is time before the extrusion reaches 140° C. in a heating step, and t2 is time before the extrusion reaches 140° C. again in a cooling step.