A Screening Approach for Rapid Qualitative Evaluation of Residual-Stress States - Application to Laser-Hardened Microalloyed Steel

摘要

Surface hardening and compressive residual stresses are keys to superior part performance in numerous applications. In this context the development of advanced laser surface treatments for new materials and complex sample shapes is a time consuming process. Eventually, determination of residual stress states by means of X-ray diffraction in the whole surface and subsurface region, respectively, is one of the main time consuming factors in terms of characterization. In many applications the provision of an adequate distribution of compressive residual stresses, however, is needed for approval of parts. In the present work it is shown that micrograph analysis can be used to provide the zero transition zone of residual stresses revealing the relevant penetration depth of the laser treatment conducted. One single surface stress scan employing standard techniques only is needed to verify the sign of residual stresses induced by the treatment. In fact, the screening approach introduced in this study enables time- and cost-efficient development processes for studying new sets of laser hardening parameters.