Properties of Cold Coiled Automotive Suspension Springs From High Strength Si-Cr-V Wire

Helical suspension springs were cold formed from three different types of material: Si-Cr steel (SAE 9254), Cr-V steel SAE 6150, and a new high strength Si-Cr-V steel. It will be shown by a direct comparison of similar springs with the same working stresses that the springs from the Si-Cr steel have about double the fatigue life and half the sag loss as those from the Cr-V steel. It is demonstrated that, while still maintaining the same fatigue life and even smaller sag losses, as found with the Si-Cr steel springs, the working stresses of Si-Cr-V springs can be increased by the same ratio as the tensile strength was increased.