| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high-strength spring superior in corrosion fatigue properties, a steel wire for the high-strength spring, and a method for manufacturing them. <P>SOLUTION: The steel wire for the high-strength spring and high-strength spring each have a composition comprising, by mass%, 0.35 to 0.50% C, 1.00 to 3.00% Si and 0.10 to 2.00% Mn, at most 0.015% P and at most 0.015% S which are limited, and the balance Fe with unavoidable impurities; and show the peak of an exothermic reaction only at 450°C or higher when the differential scanning calory of the steel wire has been measured by heating the steel wire in a temperature range from 50°C to 600°C at 0.25°C/s. The method for manufacturing the high-strength spring includes tempering a high-strength spring in such a condition that an annealing temperature (T) [K], a tempering period of time (t) [s] and an Si content [mass%] satisfy the following expression: 16,000≤(T-40×[Si%])×(31.7+logt)≤23,000. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
