Effects of sintering atmosphere on the microstructure and mechanical property of sintered 31 6L stainless steel

摘要

In the present work, N_2 , N_2 + H_2, Ar and Ar+H_2 , were used as the sintering atmosphere of Metal Injection Molded 316L stainless steel respectively. The influences of the sintering atmospheres on C, O, N contents of the sintered specimens, sintered density, grain morphology and mechanical properties were investigated. The results show that C, O, N contents of the sintered specimens can be controlled in permitted low values. The ultimate tensile strength and elongation of the specimen sintered in N_2 + H_2 atmosphere are 765 MPa and 32% respectively. Using Ar and Ar+H_2 as the sintering atmosphere, the density of the sintered specimens is 98% of the theoretical density; the pores are uniformly distributed as small spherical shape and the grain size is about 50 μm. The mechanical properties of the specimen, i. e. ultimate tensile strength 630 MPa, yield strength 280 MPa, elongation 52%, HRB 71, are much better than those of the American Metal Powder Industries Federation (MPIF) 35 Standard after being sintered in Ar+H_2.