| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel for a spring, which prevents super cooling and improves workability in wire drawing, while securing fatigue characteristics by suppressing ferrite decarburization in a steel material. SOLUTION: The method for manufacturing the steel for the spring includes: extracting the steel material which includes 0.35-0.65% C (mass%, hereinafter the same), 1.4-3.0% Si, 0.1-1.0% Mn, 0.1-2.0% Cr, 0.025% or less P (excluding 0), 0.025% or less S (excluding 0) and the balance Fe with unavoidable impurities, from a heating furnace; then hot-rolling the steel material while setting a temperature before finish rolling at lower than 1,000°C; finish-rolling the plate; keeping the plate in the range of 1,000-1,150°C for 5 sec or shorter and winding up the plate; cooling the coil to 750°C or lower at a cooling rate of 2-8°C/s; and then slowly cooling the coil to 600°C while spending 150 sec or longer after the winding-up. COPYRIGHT: (C)2011,JPO&INPIT |
