Experimental Investigation on Fatigue Crack Propagation in Surface-Hardened Layer of High-Speed Train Axles

This study examines fatigue crack growth behavior in induction-hardened S38C axle steel with a gradient microstructure. High-frequency three-point bending fatigue tests were conducted to evaluate crack growth rates (d<i>a</i>/d<i>N</i>) across three depth-defined regions: a h...

Full description

Saved in:
Bibliographic Details
Main Authors: Chun Gao, Zhengwei Yu, Yuanyuan Zhang, Tao Fan, Bo Zhang, Huajian Song, Hang Su
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Crystals
Subjects:
Online Access:https://www.mdpi.com/2073-4352/15/7/638
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study examines fatigue crack growth behavior in induction-hardened S38C axle steel with a gradient microstructure. High-frequency three-point bending fatigue tests were conducted to evaluate crack growth rates (d<i>a</i>/d<i>N</i>) across three depth-defined regions: a hardened layer, a heterogeneous transition zone, and a normalized core. Depth-resolved d<i>a</i>/d<i>N</i>–Δ<i>K</i> relationships were established, and Paris Law parameters were extracted. The surface-hardened layer exhibited the lowest crack growth rates and flattest Paris slope, while the transition zone showed notable scatter due to microstructural heterogeneity and residual stress effects. These findings provide experimental insight into the fatigue performance of gradient-structured axle steels and offer guidance for fatigue life prediction and inspection planning.
ISSN:2073-4352