Evalutation of Torsional Fatigue in Automotive Suspension Coil Spring Steels

Today's automotive suspension coil springs, developed for down-sized, aerodynamic vehicular designs, must accommodate higher levels of operating stresses.

Laboratory tests were conducted on four coil spring steels to determine whether increasing their hardness, or tensile strength, would enhance their endurance limits - the theoretical level below which fatigue failure will not occur.

These exploratory analytical tests provide strong evidence that certain silicon steels show marked improvement in endurance limits when processed to hardness levels greater than typically applied maximums.