Influence of shot-peening on the self-heating behavior and fatigue properties of 300M steel
Pierrick Lepitre, Louis-Maël Merlet, Cédric Doudard, Matthieu Dhondt, Martin Surand, Sylvain Calloch
Abstract
Shot peening is an established cold working process used to introduce residual compressive stresses on a surface and is extensively studied using conventional fatigue tests. However, it has not been widely studied using the self-heating method. Specifically, the heterogeneity of the dissipation field has not been estimated, with only an average approach being used. Previous investigations in the case of 300M steel demonstrated that the effect of shot peening on the high cycle fatigue properties can be either beneficial or detrimental. This study proposes to apply the self-heating method on polished 300M and to investigate the effect of mean stress and shot peening on the dissipation behavior. A modified self-heating model is proposed and calibrated for 300M steel. Combined with residual stress profiles, a method to compute and determine the shot peening effect on self-heating behavior through single point surface measurements is proposed. Application on 300M steel shows excellent results, the over-dissipation being mainly due to the sub-surface compressive residual stresses. The self-heating method has proven useful to quickly estimate fatigue properties of polished 300M steel. Based on the understanding of the self-heating curve of shot peened 300M steel, a quantification of shot-peening effect on fatigue limit is discussed. • Self-heating measurements give accurate estimation of 300M steel fatigue properties • Shot-peened 300M self-heating behavior is mainly due to compressive residual stress • Self-heating measurements are not relevant for shot-peened 300M fatigue properties • Due to the self-balancing stresses, bulk is subjected to tensile residual stresses • Shot-peened fatigue reduction factor is partly due to the tensile residual stresses