Oil-tempered wires and springs were prepared by adding the alloying elements such as C, Si, Mn, Cr, Mo, V and W to the base metal Si-Cr steel widely used for valve springs. The wires and springs were subjected to tension tests and warm clamping tests to examine the effects of chemical compositions on warm relaxation together with the relation between temper softening resistance and warm relation. As a result, it was found out that to improve warm relaxation the addition of Si making the matrix strong carbide-forming elements such as Mo, V and W was effective. Obvious correlation was observed between temper softening resistance and residual shear strains. Further, it was also revealed that the warm relaxation of the 2%Mo-2%Cr steels was far better than that of the Si-Cr steels.