Influence of Surface Finishing and Chemical Composition on Fatigue Strength of Steel Wire for Valve Springs

Environmental concerns have led to the development of automobile engines that are lightweight yet powerful. In consequence, the industry is now demanding an engine valve spring with higher fatigue strength and higher sag resistance.

To meet the demands, the authors studied the influence of surface finishing and chemical compositions in Chromium-Silicon Alloy Steel on fatigue strength of steel wire for valve springs. The authors confirmed that the addition of silicon improves softening resistance while tempering, and electropolishing which eliminates surface flaws on wire are effective.