HIGH-STRENGTH SPRING STEEL WIRE, HIGH-STRENGTH SPRINGS AND PROCESSES FOR PRODUCTION OF BOTH

摘要

The invention provides a high-strength spring excellent in corrosion fatigue characteristics; a steel wire for high -strength springs; and processes for the production of both. A steel wire for high-strength springs which contains by mass C: 0.35 to 0.50%, Si: 1.00 to 3.00%, Mn: 0.10 to 2.00%, P: 0.015% or below, and S: 0.015% or below with the balance consisting of Fe and unavoidable impurities, characterized in that in the differential scanning calorimetry accompanied with heating from 50°C to 600°C at a temperature rise rate of 0.25°C/s, an exothermic reaction peak is present only at 450°C or above; high-strength springs; and a process for the production of high-strength springs, characterized by conducting tempering under the conditions satisfying the following relationship (wherein T[K] is tempering temperature; t[s] is tempering time; and Si%[mass%] is content of Si): 16000 (T-40×[Si%]) × (31.7+log t) 23000