Overview of factors contributing to steel spring performance and failure

Leaf springs and coil springs are commonly used in the motor vehicle industry. Premature fatigue failure is a common failure mode. However, the reasons for these failures may be more complex and include: design deficiencies, heat treatment, steel alloy chemistry, intergranular cracking, presence of Fe-S inclusions, and grain boundary embrittlement. This paper will provide an overview of spring steel: chemistry, heat treatment, residual stress, fatigue failure, and failure analysis of leaf and coil springs.