Experimental Investigation on Effect Different Machining Processes on Rolling Contact Fatigue Life of D2 Wheel Steel

Abstract

A fine-grain layer is produced in high-speed train wheels after machining. In this article, the influence of the fine-grain layer on rolling contact fatigue (RCF) is studied using a GPM-30 fatigue tester. The results show that there is a 1-μm-thick fine-grain layer after grinding treatment. The fine-grain layer can improve the RCF life of wheel samples. The formation of RCF cracks on the sample with a fine-grain layer is divided into three stages: (1) the initiation of fine fatigue cracks is preferred in the fine-grain layer during RCF; (2) RCF cracks in the fine-grain layer propagate gradually to lead to flaking of the fine-grain layer; (3) when the fine-grain layer is flaked, RCF cracks initiate and propagate at the surface of the original microstructure. However, RCF cracks of the sample without a fine-grain layer directly initiate and propagate at the surface of the original microstructure. Therefore, the fine-grain layer can hinder the formation of RCF cracks at the surface of the original microstructure to improve RCF life.

Keywords:

• D2 wheel steel
• rolling contact fatigue
• crack
• surface microstructure
• fine-grain layer

Additional information

Funding

The authors gratefully acknowledge support from the National Key Basic Research Program of China (973) (2015CB654802) and Liaoning Doctoral Research Start-Up Fund (20170520377).