Abstract: A process for making an essentially lead-free screw machine stock alloy, comprising the steps of providing a cast aluminum ingot having a composition consisting essentially of about 0.55 to 0.70 wt. % silicon, about 0.15 to 0.45 wt. % iron, about 0.30 to 0.40 wt. % copper, about 0.8 to 0.15 wt. % manganese, about 0.80 to 1.10 wt. % magnesium, about 0.08 to 0.14 wt. % chromium, nor more than about 0.25 wt. % zinc, about 0.007 to 0.07 wt. % titanium, about 0.20 to 0.8 wt. % bismuth, about 0.15 to 0.25 wt. % tin, balance aluminum and unavoidable impurities; homogenizing the alloy at a temperature ranging from about 900.degree. to 1060.degree. F. for a time period of at least 1 hour; cooling to room temperature; cutting the ingot into billets; heating and extruding the billets into a desired shape; and thermomechanically treating the extruded alloy shape.

Abstract: A process for making an essentially lead-free screw machine stock alloy, comprising the steps of providing a cast aluminum ingot having a composition consisting essentially of about 0.55 to 0.70 wt. % silicon, about 0.15 to 0.45 wt. % iron, about 0.30 to 0.40 wt. % copper, about 0.8 to 0.15 wt. % manganese, about 0.80 to 1.10 wt. % magnesium, about 0.08 to 0.14 wt. % chromium, nor more than about 0.25 wt. % zinc, about 0.007 to 0.07 wt. % titanium, about 0.20 to 0.8 wt. % bismuth, about 0.15 to 0.25 wt. % tin, balance aluminum and unavoidable impurities; homogenizing the alloy at a temperature ranging from about 900.degree. to 1060.degree. F. for a time period of at least 1 hour; cooling to room temperature; cutting the ingot into billets; heating and extruding the billets into a desired shape; and thermomechanically treating the extruded alloy shape.