Characterization of Residual Stresses and Retained Austenite on 416 Stainless Steel via X-Ray Diffraction Techniques

摘要

Residual stress (RS) and retained austenite (RA) measurements performed using x-ray diffraction (XRD) techniques have been useful to assist in evaluating the quality of parts both in the field and in production environments for decades. Single spot checks at critical locations are often performed providing basic information for a given testing requirement at a specific location. Although this is useful information, the highest levels of RS or RA present in the component may be missed when performing single spot checks only if surface RS or RA gradients are present. To achieve a more in depth understanding of the range and distribution of RS and RA in a component, a relatively large area was characterized using the mapping approach on a heated and quenched 416 stainless steel sample. The results found using this characterization technique indicate that RS and RA levels are not uniform over the area examined; thus it has been demonstrated that the one point approach is not adequate in this instance since the lowest and highest levels of RS and RA would be missed without mapping. For this reason, it is recommended that the mapping approach be adopted whenever gradients are present to fully and efficiently characterize RS and RA and subsequently to help correctly assess the quality of the part.