Bainite Transformation Characteristics of High-Si Hypereutectoid Bearing Steel

Zhihui Chen,Jianfeng Gu,Lizhan Han

doi:10.1007/s13632-017-0410-5

Zhihui Chen, Jianfeng Gu + Show 1 more

Open Access

https://doi.org/10.1007/s13632-017-0410-5

Copy DOI

Abstract

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.

Highlights

IntroductionThe hypereutectoid steel grade AISI 52100 (1% C, 1.5% Cr) (all units are given in wt.%) steel has been widely used for manufacturing high-performance bearings for over a century [1]
The hypereutectoid steel grade AISI 52100 (1% C, 1.5% Cr) steel has been widely used for manufacturing high-performance bearings for over a century [1]
The dilatometric amount in length induced by isothermal transformation increased with the decreasing transformation temperature, ensuring the transformation was finished

Summary

Introduction

The hypereutectoid steel grade AISI 52100 (1% C, 1.5% Cr) (all units are given in wt.%) steel has been widely used for manufacturing high-performance bearings for over a century [1]. The addition of silicon (Si), in combination with an increased alloying content, has been recognized as a way to improve bearing performance in particulate contamination environments [2, 3]. This improvement is thought to be related to the presence of stable retained austenite (RA) [3,4,5]. It has been reported in the literature that RA leads to cyclic hardening through martensitic transformation in service processes of bearings [3,4,5]. The former determines the chemical driving force for the transformation of austenite to

Objectives

Methods

Results

Conclusion