On the Influence of Laser Cladding and Post-processing Strategies on Residual Stresses in Steel Specimens

Thermal cycles during laser cladding can alter mechanical properties of the original part significantly. In case of cyclically loaded parts residual stresses are suspected to be a property strongly determining fatigue life. Therefore, in this paper the influence of processing and post-processing strategies on resulting residual stresses are determined by neutron-diffraction. A low-alloy as well as a high-alloy steel have been considered within this study, both cladded with the Co-based superalloy Stellite 21. Processing speed and post-treatment by laser annealing and by deep rolling strategies have been tested. Residual stresses in low-alloyed steel show high sensitivity on applied treatment strategies. In the present study only deep rolling induced compressive residual stress close to the part surface. In high-alloy steel compressive stress in this area resulted directly after laser cladding, where its magnitude depends on processing speed. A compressive residual stress statewhich is suspected to be beneficial for fatigue strength could be achieved at the two representative steels.