Patent ID: 10752971

Abstract:
A high strength spring containing, by mass %, C: 0.40 to 0.50%, Si: 1.00 to 3.00%, Mn: 0.30 to 1.20%, Ni: 0.05 to 0.50%, Cr: 0.35 to 1.50%, Mo: 0.03 to 0.50%, Cu: 0.05 to 0.50%, Al: 0.005 to 0.100%, V: 0.05 to 0.50%, Nb: 0.005 to 0.150%, N: 0.0100 to 0.0200%, P: limited to be less than or equal to 0.015%, S: limited to be less than or equal to 0.010%, and the balance of Fe and inevitable impurities, wherein a Nb-compound including at least one of Nb-carbide, Nb-nitride and Nb-carbonitride is included, and wherein a V-compound including at least one of V-carbide and V-carbonitride that is precipitated around the Nb-compound is included.