Influence Of Residual Stress On Fatigue Of Carburized And Shot Peened Notched Specimens

Author:  Ogawa, Yamada, Saruki, Yokoi, Inuzuka
Source:  Conf Proc: ICSP-4, (p.445-454)
Doc ID:  1990037
Year of Publication:  1990
Abstract:  
Bending fatigue tests were carried out on gears and three differently notched specimens simulating gear-tooth root, which were shot-peened under different conditions without machining after heat treatment. The results indicated that the fatigue strengths of shot-peened specimens and gears were strongly affected by the residual stresses beneath the surface, though not so much by the changes in the hardness and surface roughness induced by shot peening. The correlation between the fatigue limits and the residual stresses was also examined using a simple model based on the critical depth criterion. Assuming the critical depth influencing fatigue properties to be 0.05 mm, the fatigue limits of shot-peened specimens with different notch-radiuses correlated well with the residual stresses induced by shot peening. Descriptors: Shot peening; Fatigue strength; Carburizing; Notched specimen; Helical gear; Residual stress; Oxidation layer; Critical depth; Stress gradient