Effect Of Alloying Elements And Shot Peening On Fatigue Strength Of Carburized Steel

Author:  Nakamura, Matsushima, Hasegawa, Kouka
Source:  Conf Proc: ICSP-4, (p.485-494)
Doc ID:  1990021
Year of Publication:  1990
Abstract:  
A new carburizing steel and a manufacturing process with high fatigue strength been in demand because of the needs for higher engine output and smaller machine size. In accordance with these trends, the authors investigated the alloy design of carburized steel from the point of increasing residual compressive stress on surface layer when shot peened. As a result, it was found that raising the Mo content inhibited the formation of non-martensitic layer and increased the retained austenite content on surface layer. Furthermore, it was found that when using high Mo-low Si case hardening steel, raising shot peening intensity made it possible to greatly increase the residual compressive stress, thereby improving the bending fatigue strength by more than 100% in comparison with that of carburized conventional steel. Descriptors: Fatigue strength; Carburizing; Shot peening; Residual stress; Retain austenite; Internal oxidation; Crack propagation