Optimum outgassing cycles for aluminum and stainless steel

Outgassing rates were measured for a modified 7075T6 aluminum and 304L stainless steel, for two degrees of finish, at temperatures of 285 deg F to 392 deg F, for times of 0.5 to 72 hours. The results were analyzed to determine optimum time and temperature cycles for outgassing. Optimum cycles were determined with and without the limitations of a graph. The graph related allowable time at temperature to a 5 percent or less reduction in room temperature properties of 7075T6 aluminum. For aluminum, within the limits set by reduction in mechanical properties, the optimum cycle tested was 40 hours at 285 deg F. Disregarding the limits, optimum outgassing was achieved at the highest temperatures and longest times tested, for both aluminum and stainless steel.