Development of a New Light-Weight Suspension Coil Spring

Author:  Sakakebara Kusakari Nakano Yasuda Sugimoto Watanab
Source:  p 27-36
Doc ID:  1993114
Year of Publication:  1993
Abstract:  
This newly developed helical spring can be used at a stress level up to 1300 MPa. The material is composed of Fe-C-Si-Mn-Ni-Cr-Mo-V alloy. Its strength-toughness balance was greatly superior to that of other spring steels. To improve the fatigue strength at a higher stress level, decarburization at the surface upon austenitizing was severely controlled, applying induction heating. Then, a special shot peening process, introduced for the first time, was applied to obtain a surface of over 1000 MPa. The spring was first applied to a 1992 TOYOTA model car. Plan are to increase the use since the spring material achieves a weight reduction of at least 30% and, possibly, 35 to 40%.