COLD-FORMED SPRING OF HIGH FATIGUE STRENGTH AND HIGH CORROSION AND FATIGUE STRENGTH, AND STEEL FOR THE SPRING

摘要

PROBLEM TO BE SOLVED: To provide a cold-formed spring with both corrosion resistance and durability, and steel for the spring.;SOLUTION: A stock material comprises, by weight, 0.45-0.52% C, 1.80-2.00% Si, 0.30-0.80% Ni, 0.15-0.35% Cr, and 0.15-0.30% V, and the balance substantially Fe. A wire of this composition is induction-heated at 920-1,040°C for 5-20 sec, and tempered at 450-550°C for 5-20 sec after the hardening so as to obtain the hardness of HRC 50.5-53.5. The material is subjected to shot-peening to generate residual stresses of ≥ -600 MPa at the position of 0.2 mm below the surface.;COPYRIGHT: (C)2005,JPO&NCIPI