Spring steel of high strength and high corrosion resistance

Abstract

Disclosed is a spring steel for a high corrosion resistant and high strength, which exhibits an excellent drawability without softening heat treatment after hot rolling, and which has a strength of 1900 MPa or more by quenching and tempering and an excellent corrosion resistance. The spring steel contains elements of C, Si, Mn and Cr, and elements of Ni and/or Mo in suitable amounts, the balance being essentially Fe and inevitable impurities, wherein the elements satisfy the following requirement: 2.5.ltoreq.(FP).ltoreq.4.5 2.0.ltoreq.(FP/log D).ltoreq.4.0 where D is a diameter (mm) of the rolled material, and FP=(0.23[C]+0.1).times.(0.7[Si]+1).times.(3.5[Mn]+1).times.(2.2[Cr]+1).tim es.(0.4[Ni]+1).times.(3[Mo]+1) in which [element] represents mass % of the element.

Dependencies are inferred from the claim text.