Precipitation hardening of an aluminium alloy

摘要

Three-stage heating and cooling pretreatment, finally stabilizing the grain structure under reducing temperature, for at least 420 hrs, preferably for 1000 hrs, produces stabilized grain structure with good mechanical properties: hardness HB up to 65 (2.5/62.5/16); limiting expansion Rp0.2 up to 140 MPa, preferably 130 MPa; tensile strength Rm up to 270 MPa, preferably 240 MPa; and uniform expansion before area reduction exceeding 18%. If appropriate, after extraction of the component from the mold, it is precipitation-hardened at a temperature of 165 degrees C-190 degrees C, over an interval of 12-38 M.