Mechanical properties of Fe–Mo–Mn–Si–C sintered steels

Abstract

Four Fe–Mn–Si master alloy powders with the compositions Fe–35%Mn–14%Si, Fe–35%Mn–20%Si, Fe–45%Mn–20%Si and Fe–60%Mn–14%Si were made by the cast milling method, and used to produce Fe–Mo–Mn–Si–C sintered steels. The effects of master alloy composition and sintering atmosphere on the mechanical properties and dimensional change of the sintered steels were studied. The steels were sintered either at 1250°C for 30 min in hydrogen–30% nitrogen or at 1120°C for 30 min in hydrogen and nitrogen–10% hydrogen with different dewpoints. After transient liquid phase sintering, the ultimate tensile strength, yield strength and hardness increase and elongation decreases with increasing contents of manganese and carbon. The dewpoint of sintering atmospheres had little effect on the properties, probably as the addition of manganese and silicon was in the form of a master alloy. The highest tensile strength and smallest dimensional change were obtained in a steel with a composition of Fe–0.85%Mo–1.40%Mn–0.8%Si–0.7%C.