Failure Cases and Cause Analysis of Spring on Rail Transit

This paper summarizes recent failures of springs used in rail transit and analyzes their specific impact, providing a reference for improving spring reliability and preventing future failures. By employing various material characterization techniques and analyzing several failed rail transit springs, the study identifies problems related to raw materials, heat treatment, manufacturing processes, and usage, thereby clarifying the specific causes of these failures. The research results indicate that the failure in Case 1 was due to improper control of the heat treatment process, leading to excessive surface decarburization. Case 2 was caused by grinding cracks resulting from improper grinding; and the failure in Case 3 was attributed to uneven thickness on the inner side of the support ring due to improper spring winding. Based on these failure analyses, the study finds that early spring failures are primarily related to factors such as raw materials, heat treatment, manufacturing processes, and usage.