Bainite Transformation Characteristics of High-Si Hypereutectoid Bearing Steel

In this work, the bainite transformation characteristics of a high-Si hypereutectoid (1.3 wt.% Si, 1 wt.% C) bearing steel was analyzed by means of microstructural observation and dilatometric experiment. The results conclude that bainitic transformation occurs by the displacive mechanism at 250–350 °C. However, suppression of carbide precipitation from austenite, caused by the addition of 1.3 wt.% Si, leads to an increase in the effective carbon available for carbon enrichment in austenite. This reduces the bainite transformation kinetics. The incomplete transformation phenomenon can be explained in terms of the diffusionless growth of bainitic ferrite subunits and the suppression of carbide precipitation from carbon-enriched austenite.