Aluminium alloy forgings - from material cast heat treated and worked under particular conditions to obtain improved mechanical properties

摘要

An alloy containing by wt. 4.8 to 8.5% Zn, 1.7 to 3.5% Mg, 0.8 to 2.5% Cu, =1 gram control element selected from 0.1 to 0.75% Mn, 0.05 to 0.4% Cr, 0.05 to 0.3% Zr, 0.05 to 0.3% V and 0.05 to 0.3% Mo, bal. Al, is cast with a gas content of is not 0.15 ml/100 gm with a minimum chill rate through the solidification zone of 2 degrees F/sec. It may then be homogenised at is not 860 degrees F, worked into forging stock at is not 750 degrees F with a ratio of =8:1, soaked at 900 degrees-970 degrees F for =2 hrs and forged at less than =750 degrees F. The product may be soln. treated at =900 degrees F and aged either at 215 degrees to 250 degrees for =50 hrs, or at that temp. for =6 hrs. and then at 340 degrees to 360 degrees F for a time equivalent to 7 1/2 to 9 1/2 hrs at exactly 350 degrees F.