Environment-conscious Cu Free Sintered Steels (Report 2) Effect of Sintering Temperature

Abstract

Fe-Cu-C sintered steels are widely used for automobile parts. In case of reusing these sintered steels as the raw materials of wrought steels, it becomes to be a problem that Cu contamination deteriorates hot workability of wrought steels. In order to recycle the scrapped sintered steels, Cu free sintered steels are strongly required. We developed new Fe-Mn-Si-C sintered steel as a candidate material to the conventional Fe-Cu-C sintered steels. The developed sintered steel shows superior mechanical properties compared with the conventional sintered steels by adding Mn and Si elements to the Fe-Mn-Si ternary master alloy (FeMS) powder.In this study, the influence of sintering temperature and also particle size of FeMS powders on the mechanical properties of the new Fe-Mn-Si-C sintered steels were investigated. The tensile strength is improved by not only rising sintering temperature and also adding the fine FeMS powder. In particular, this improvement is considered to be resulted from the microstructural changes as follows. The addition of the fine FeMS powder works to increase amount of the fine pearlite phase in whole of the microstructure and also inhibit the precipitation of the martensite phase at the Mn and Si enriched regions.