MANUFACTURE OF A MG SI TYPE CORROSION RESISTANT* FREE CUTTING ALUMINUM ALLOY PIPE OR ROD WITH LITTLE RESIDUAL

摘要

PURPOSE:To manufacture an Al alloy pipe or rod with little residual stress by hardening an Al-Mg-Si type corrosion resistant, free cutting alloy, followed by stretch leveling, roll leveling and tempering under specific conditions. CONSTITUTION:An Al-Mg-Si type corrosion resistant, free cutting alloy is hardened and stretch leveled at a stretch ratio of 0.5-1.0%to enhance the dimensional accuracy such as roundness as well as to relieve the residual stress due to the hardening. Next, the alloy is roll leveled and stretch leveled at a stretch ratio of 0.5-1.0% to relieve the residual stress formed by the roll leveling. The alloy is then held at 210-250 deg.C for 1-2 hr to be tempered to further relieve the residual stress. By this method an Al-Mg-Si type corrosion resistant, free cutting Al alloy pipe or rod with little residual stress is obtd. without lowering the strength, and it is used for parts of optical instruments, etc.