No abstract

The effects of different sintering atmospheres (nitrogen and argon) on the densification, microstructure, and mechanical properties of HK30 stainless steel were studied. Compared with those of the samples sintered in Ar, sintered samples in N 2 had a lower density and higher N content. Some of the N atoms dissolved into the austenite matrix, and others were combined with metal atoms to be precipitated along the grain boundaries. Samples sintered in N 2 had a higher hardness than those in Ar. The hardness decreased with the distance from the edge to the center. The highest hardness was 360 HV 1.0 at the edge, the lowest one was 220 HV 1.0 at the center. The samples sintered in N 2 had a higher tensile strength than those sintered in Ar at testing temperatures from room temperature to 1000 °C.

Recently, metal injection molding (MIM) has emerged and rapidly developed as a powder metallurgy net-shaping process. Increasing attention has been paid to this process as a promising technology to produce small parts with complex geometric shapes [1,2]. Although MIM process is a cost-effective technology to precisely fabricate large quantities of small and intricate parts, researchers and manufacturers are highly concerned with the costly raw materials used in the process [3]. Such costly applications of MIM involve fine (< 10-20 µm) powders with spherical particle shape that are typically manufactured by gas atomization (GA) process. However, the cost of applying MIM to stainless steel (SS) powder with irregularly shaped particles using water atomization (WA) process is only one fifth of that