Effect of Chemical Composition on Sag Resistance of Suspension Spring

This paper summarizes a laboratory study aimed at revealing the effect of chemical elements. Si, Cr, Mo and V, on the sag resistance and developing new steels with all the characteristics required for suspension coil spring in comparison with AISI 9260. It was found that as far as sag resistance is concerned an optimum silicon content exist (1.5 silicon) and chromium deteriorates sag resistance and molybdenum and vanadium improve it. Further studies showed that Si-Cr-V steels are the best spring steels available, particularly 1.5Si-0.5Cr-G.2V steel has all the required characteristics, e.g., good sag resistance, good decarburizing resistance and sufficient hardenability.