Residual Stresse tained

Proceedings of ICSB1. Editor: A. Niku-Lari, X-ray diflractometry has been used to examine the variation of residual stress across shot peened surfaces, the transformation of austenite to rnartensite on peening and the decay of surface residual stress during fatigue testing of peened specimens. It is shown that masking gives rise to tensile surface residual stresses adjacent to the peened area. Peening of austenitic stainless steel produces surface martensite in amounts that depend upon the composition of the steel. Transformation of retamed austenite on peening of carburised steel is found to give a substantial improvement in the surface and sub-surface residual stresses. Shot peened austenitic stainless steel is found to lose its compressive surface residual stress on fatigue testing at high levels of applied alternat-ing stress. The fatigue and corrosion fatigue properties of the shot peened stainless steel are then found to be inferior to those of as-polished steel but are superior at lower stress levels. KEYWORDS X-ray diffractometry; shot peening; residual stress; austenite transformation; corrosion-fatigue; steel