Structure and properties of steel produced by metal injection molding

Austenite stainless steel produced by metal injection molding (MIM process) is studied, including its structure, phase composition, and mechanical properties of initial feedstock and sintered material. Prepared feedstock consists of cylindrical granules with the diameter of approximately 3.5 mm. The main feedstock material is a mixture of chrome-nickel and steel powders. Polyacetal is used as a plastic binder. Upon sintering of the feedstock, the material is synthesized with chemical composition, structure, and mechanical properties similar to those of austenite stainless steels. The material density after sintering is higher than 98% of theoretical value. It is established that, upon sintering, a phase transformation occurs: the initial ferrite phase is transformed into the austenite phase. The phase transformation is promoted by nickel contained in initial powder mixture. The microhardness of the sintered material is 1.6 GPa; the elastic modulus is 115 GPa.