Improved Fatigue Strength of Valve Springs and Sheet Springs by Applying a New Surface Treatment Technology

Author:  Yamada, Saitoh, Ishida, Uzumaki, Suzuki, Teratoko
Source:  Suncall Corporation
Doc ID:  2001000
Year of Publication:  2001
Abstract:  
Authors: Yoshire Yamada, Tadashi Saitoh, Masaaki Ishida, Kazuhiro Uzumake, Hiroshi Suzuki and Keiichiro Teratoko of the Suncall Corporation The peening of fine steel beads with the diameter less than 80 micrometers onto spring surface (SS Treatment) was found to improve the fatigue limits of the spring effectively since the surface compressive residual stress and surface hardness were improved significantly. As an example, by applying this technology to the non-nitrided valve springs made from the so-called high tensile oil tempered wire, the fatigue limit was increased to the nearly equivalent level as the nitrided and conventionally shot-peened valve springs made from the same high tensile wire. This means that the SS Treatment can be used as a substitute to the nitriding process in order to improve the fatigue property of valve springs. The improved fatigue strength by applying this technology to nitrided valve springs is also described in this article.