Effect of Shot-Peening Duration on the Relaxation & Fatigue Properties of Engine Valve Springs

Author:  Hayes, M.P.
Source:  Impact Surface Treatment, British Impact Treatment Sp. Res. & Man. Eng. p79
Doc ID:  1986029
Year of Publication:  1986
Abstract:  
Shot peening is used to improve the fatigue performance of springs and many engineering components, but the process has a detrimental effect on static stress relaxation. Relaxation performance is vitally inportant aspect of the operation of springs. This paper considers the effect of shot-peening exposure time on the fatigue and relaxation of compression springs made from a typical engine valve spring quality wire. The relaxation levels that can be expected as a consequence of shot-peening are quantified. Hot pre-stressing can be employed to reduce relaxation of springs and the effectiveness of this process is also quantified.