Effects of pulsed laser hardening of cylindrical surfaces on fatigue behavior

Abstract

The issues of the of laser hardening of the plain bearing effects on the fatigue strength of the crankshaft neck journal are discussed in this article. The crankshaft destruction of the crankshaft leads to catastrophic consequences, especially for heavy diesel engines. The article substantiates the assertion of a decrease in the fatigue strength of steels after pulsed laser hardening treatment of the friction surface to increase the wear resistance of a plain bearing. The process of formation of a surface hard layer of steel and the formation of dimple-shaped stress concentrators on it after interaction with a laser pulse is studied. Factors affecting the fatigue behavior of materials are analyzed. Particular attention is paid to the formation of a residual stress state in the surface layer and the role of surface defects on the fatigue behavior of steel. The assumption about the possibility of reducing the decrease in fatigue strength by optimizing the technological parameters of laser processing is substantiated. On the basis of the study, it is proposed to limit the energy of the laser pulse, preventing the surface from melting.