Method for manufacturing a high-strength spring

摘要

A spring steel containing 0.35 to 0.50% of carbon is refined to the hardness of phi 2.50 to 2.70 mm in Brinell indentation diameter (HBD) by rapid cooling for quenching and tempering. This spring steel is subjected to warm shot peening at a temperature of 150 DEG to 300 DEG C. (423 to 573 K.) by using long-lived practical shots with the normal hardness of phi 2.65 to 2.80 mm in HBD, whereupon a high-strength spring is obtained having a compressive residual stress in its surface and enjoying the maximum shearing stress of 110 to 135 kgf/mm2 (1080 to 1325 MPa).