Residual stress evaluation in service exposed shot peened spring by micromagnetic and XRD techniques

Micromagnetic Barkaussen emissions technique is used to determine the surface stress-state of shot peened suspension spring which failed while in service. Different surface stress states along the circumference of the spring are observed which are confirmed by XRD. The presence of high tensile stress at the subsurface is also indicated by XRD. Different surface stress occurrence of high tensile stress at the subsurface and presence of high inclusion ratings in the material are found to be the cause of failure of spring.