Samuel Tesfaye
University of Trento, Italy
Title: Microstructure and residual stresses of shot peened Mo alloyed carburized PM steels
Biography
Biography: Samuel Tesfaye
Abstract
Shot peening increases the fatigue resistance of steels due to the accumulation of compressive residual stresses in the surface layers. In porous sintered steels, an additional effect is due to surface densification. Surface densification is inversely proportional to the resistance of the steel to plastic deformation. In the present work, two sintered steels having different Mo content were gas carburized and shot peened. The effect of shot peening on the surface densification and on the residual stresses was investigated, Surface densification was investigated by image analysis, to measure the residual porosity along the distance from the surface. Through the analysis of the pore morphology, the fraction of the load bearing section profile was calculated using a model that correlates it to the fractional porosity and the parameter fcircle. The effect of the resistance to plastic deformation of the carburized steels on the surface densification and on the residua stress profile was this way investigated and discussed.