Improvement of Fatigue Strength of Nitrided High-Strength Valve Springs by Application of a New Super Fine Shot-Peening Techn

Author:  Yamada, Teratoko, Saitoh, Sasada, Yanagihara
Source:  SAE: 2001 World Congress, Detroit, MI, March 5-8, 2001, 2001-01-0834
Doc ID:  2001015
Year of Publication:  2001
Abstract:  
ABSTRACT The peening of fine steel beads with diameters less than 80um (referred to as SS Treatment in this paper) on the surface of nitrided and then conventionally shot-peened (with 0.6mm diameter cut steel wires) high-strength helical springs made from developed high strength valve spring wire, was found to effectively improve spring fatigue strength. This improved fatigue strength is mainly the result of very high compressive residual stress caused by work hardening of the spring surface layer without inducing deleterious surface qualities such as harmful surface micro-fissuring or surface roughness.