Injection Molding of 17-4 PH Stainless Steel

17-4 PH stainless steel has been successfully formed by powder metallurgy (P/M) injection molding. Injection molding is a relatively new P/M technique. In this process, metal powder is mixed with a plastic binder, and the part shape is injection molded as in plastics fabrication practice. The binder is extracted, and the part is sintered to 95-96% of full density.

Sintering atmospheres and temperature profiles for optimized material properties were developed. Material mechanical properties were evaluated by tensile, impact, and fatigue tests. Five prototype fin bases for a missile were fabricated. The effect of Hot Isostatic Pressing was determined. The mechanical properties compare favorably to those of investment cast or wrought 17-4 PH steel.