MANUFACTURE OF STEEL WIRE FOR SPRING WITH SUPERIOR SETTLING RESISTANCE

PURPOSE:To obtain a steel wire for a spring with superior settling resistance used as the material of a cold formed suspended spring for a car by tempering a wire rod while plastically working it with dies at a prescribed reduction rate of area. CONSTITUTION:A wire rod straightened almost perfectly with a straightener is fed to a heater and hardened. The hardened wire rod is immediately fed to a heater and heated to the tempering temp. During the heating for tempering, the rod is plastically worked with dies or roller dies at >=10% reduction rate of area, so the rod is tempered while producing a strain in the rod, and it is cooled to ordinary temp. By this method a steel wire for a spring with superior settling resistance used as the material of a cold formed suspended spring for a car is obtd.