Effect of Rare Earth Y on Microstructure and Mechanical Properties of High-Carbon Chromium Bearing Steel

Abstract

The effect of rare earth Y on the microstructure and properties of high-carbon chromium bearing steel in different heat treatment processes has been studied. The microstructure and mechanical properties of the bearing steel under hot rolled, annealed and quenched and tempered conditions were compared and analysed, focusing on the effect of inclusions on fatigue performance. The addition of rare earth Y improves the microstructure, Vickers hardness, tensile strength, impact toughness and fatigue properties of bearing steel. The results show that rare earth Y can refine and spheroidise cementite, make the distribution of cementite more uniform, enhance the strengthening effect of the second phase and reduce the stress concentration caused by the shape of cementite. At the same time, the formation of network cementite is inhibited and the harm to grain boundary is reduced. It also has a refining effect on the grain, and the refined grain can achieve better mechanical properties. In addition, by modifying the oxides and sulphides in the steel, the properties of the steel are also improved, particularly in the quenched and tempered state.

Keywords

• rare earth Y element
• high carbon chromium bearing steel
• inclusions
• fatigue