Valve Spring Wire

Chrome-silicon or chrome-silicon-vanadium alloyed steel wire that has 0.50 to 0.70 percent carbon. Valve springs are typically made by cold coiling of wire that has been subjected to shaving, cold drawing, hardening and tempering. Fatigue strength and sag resistance are two major factors. Tensile strength has increased over the years from 1700 MPa (247 ksi) to as much as 2150 MPa (312 ksi). Nitriding and special designed shot peening can further enhance the fatigue properties. Valve springs in applications working at elevated temperature or corrosive atmosphere are made of a precipitation hardened stainless steel grade 177 PH (AISI 631).