C和Nb添加对金属注射成形420不锈钢组织及性能的影响

摘要

通过添加石墨改变420不锈钢的C含量,研究了C含量变化对金属注射成形420不锈钢致密化过程、显微组织以及力学性能的影响,并将其与含铌420不锈钢进行对比.结果表明:C含量的增加在烧结初期能够促进致密化;但在烧结中后期反而阻碍致密化.金属注射成形420不锈钢的硬度随着C含量的增加而提升,但增加C含量使晶粒粗化从而降低了试样的抗拉强度.添加Nb有利于孔隙消除从而促进致密化,在形成弥散分布的碳化物第二相颗粒的同时能够降低脱碳量,有利于提升金属注射成形420不锈钢的硬度.本文对造成这些性能变化的机理进行了研究和探讨.%Graphite was added into the 420 stainless steel to change the carbon content.The effect of the change of carbon content on the densification process,microstructure and mechanical properties of metal injection model 420 stainless steel was investigated.And it was compared with the 420 stainless steel contain niobium.The results show that the increase of carbon content can promote the densification process at the early stage of sintering,but it hinders the densification process in the middle and late stages of sintering. To MIM420 stainless steel samples, with the increase of carbon content,their microhardness increases.But the increase of C content makes the grain coarsen and then reduces the tensile strength of the sample.The addition of Nb eliminates the pore and promotes the formation of the second phase carbide,which degrades the decarburization and improves the microhardness of MIM420 stainless steel.This paper studied the mechanism that causes the changes in properties.