Anomalies in X-Ray Residual Stress Measurements in Cold-Rolled Steels

摘要

In residual stress measurements with x-rays, the interplanar spacing is assumed to alter monotonically with the tilt psi of the specimen to the x-ray beam; the calculation of the stresses is based on this assumption when either the well-known two-tilt or sin sq psi methods are employed. But in materials with strong texture, large oscillations have sometimes been reported. A method proposed in the literature for evaluating stresses in such a situation as resulting from anisotropy has been tested and shown to provide a reasonable stress system; the texture must be known in detail, so as to calculate the effective elastic constants. More importantly, the theory predicts that the simpler methods and measured x-ray elastic constants can be used, and without knowledge of the texture, if hoo and hhh reflections are employed; this has been verified experimentally in this study. It is recommended that such reflections be employed in the future, rather than the common ones now utilized. (Author)