Failure analysis of an automobile valve spring

This paper presents the failure analysis of an automobile valve spring whic h failed in service. The fractured surfaces as well as the surface of the s pring material close to the fractured surface were examined in a scanning e lectron microscope at suitable magnifications. Optical microscopy was perfo rmed to evaluate the basic microstructure of the as-received material. Deta iled electron microscopic studies have indicated that the failure was due t o the presence of nonmetallic inclusions near the surface of the spring mat erial. (C) 2001 Elsevier Science Ltd. All rights reserved.