Thermal Processing Optimization of Injection Molded Stainless Steel Powders

Abstract

Stainless steels constitute the largest materials application group for powder injection moulding. Because of the importance of these alloys, much attention has been directed to the optimization of the thermal processing, including carbon contamination control during binder burnout and sintering. Densification in sintering has been mastered such that high final densities and competitive mechanical properties are available. Property optimization and attainment of precise final shapes depend on close control of the sintering temperature, since supersolidus liquid phase sintering is often employed to attain densification. Powder characteristics and processing details are given for obtaining optimal structures in 17-4 PH stainless steel by powder injection moulding. Much progress has occurred in working with lower cost water atomized powders that can be easily densified in spite of oxide surface layers.