: The effects of shot peening on the fatigue life of machine elements

Abstract

For increasing the resistance to fatigue and wear, different methods for improvement of contact layers properties are used. First of all, the improvement of properties is realized by heat treatment (induction and flame hardening), chemical-heat treatment (carburizing and nitriding) and plastic surface forming (surface forming by rolls, disks and balls, as well as shot-peening). The paper gives detailed explanation of the shot peening procedure, which involves the ejection of shots at high speed onto the forming object. The intensity of impact is the function of the kinetic energy and angle at which the shot hits the forming object. Thereat, smaller or larger increase of hardness occurs on surface layers, remaining stresses are made, surface topography is changed, and, in some cases, the structural changes are possible (disintegration of remaining austenite). This all leads to increase of fatigue life of elements subjected to shot-peening. The influence of specified effects on the increase of fatigue life depends on strength of material subjected to shot-peening but also on conditions at which the shot-peening process is performed. This paper will present the influence of shot peening on the increase of fatigue life of different parts.