Rolling Contact Fatigue Performance of a Newly Developed Wheel Steel for 400 km/h High-Speed Trains

Abstract

The progressive escalation of operational velocities in high-speed railways has intensified cyclic contact stresses at wheel–rail interfaces, leading to accelerated fatigue failure. Hence, it is essential to create new wheel–rail materials with superior performance to align with the requirements of high-speed railway systems. This paper introduces a newly developed high-speed wheel steel (CLD400) that demonstrates enhanced rolling contact fatigue (RCF) performance and the influence of running speed on RCF damage in wheel steel. The results reveal that the CLD400 wheel steel exhibits excellent RCF life, which is 5.9 times higher than that of ER8 wheel steel. The performance of wheel steel can be effectively enhanced by decreasing the size of the austenite grain, pearlite colony, and interlamellar spacing, while increasing the pearlite content. In situ observations indicate that under oil-lubricated conditions, cracks gradually develop on the contact surface of the wheel steel and eventually expand into noticeable peeling pits, leading to material failure. As the cycles increases, the area and perimeter of defects on the wheel steel contact surface gradually increase, whereas the shape factor gradually decreases. As running speed increases, the deterioration of the wheel's steel material begins sooner, although with a reduced level of severity. The force driving crack growth decreases with speed increases, resulting in smaller RCF crack sizes. These findings enable the targeted design of wheel materials for 400 km/h high-speed trains.

Graphical abstract