Characterization of Residual Stresses on Steel Coil Springs via X-Ray Diffraction Techniques

It is well known that manufacturing operations produce material conditions that can either enhance or debit the fatigue life of production components. One of the most critical aspects of material condition that can have a significant impact on fatigue life is residual stress (RS) [1, 2]. When springs are manufactured, the spring stock may undergo several operations during production. Additional operations may also be introduced for the purpose of imparting the spring with beneficial surface RS to extend its fatigue life and increase its ability to execute the task it was designed to perform. The resultant RS present in production springs as a result of the various fabrication and processing operations applied can be predicted and modeled, however, RS measurements must be performed in order to quantify the RS state with precision. X-ray diffraction (XRD) techniques can be used to determine the RS state of such components precisely, thus enabling manufacturers the ability to accurately and quantitatively characterize and control the effects of their production processes [3].