Development of High-Strength Suspension Coil Springs with Improved Corrosion Fatigue Strength

Abstract

For the weight reduction of suspension coil springs for automobiles, high-strength steel has been developed. Generally, strength and corrosion fatigue shows contradictory behavior, so the technological basis is to improve corrosion fatigue strength in addition to durability and sag resistance. As a solution for the problem, element design which improved the performance against corrosion and optimum condition of shot peening process were studied. Thus the high-strength suspension coil springs in this paper obtained superior corrosion fatigue strength, compared with the spring made of SUP7. Moreover, as a new basic evaluation method, corrosion fatigue test of springs with an artificial pit was proposed.