| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a seamless steel pipe as a raw material for parts excellent in bending-fatigue strength and rolling-fatigue service life under foreign material-mixed environment without impairing the quality by surface flaw and decarbonization. SOLUTION: The method for manufacturing the seamless steel pipe for high-strength carburized parts excellent in the bending fatigue and the rolling fatigue service life in a foreign material-mixed environment comprises the steps of: subjecting a steel material composed of, by mass, 0.10-0.35% C, 0.35-1.00% Si, 0.20-0.60% Mn, ≤0.030% P, ≤0.003% S, 1.50-3.00% Cr, 0.005-0.050% Al, 0.01-0.10% Nb, 0.003-0.025% N and the balance Fe with inevitable impurities to a pierce-rolling at ≥1,240°C heating temperature to form the steel pipe; cooling the steel pipe to the Ar<SB>1</SB>point or lower at ≥0.05°C/s cooling speed; and reheating the steel pipe to 900-1,080°C to apply the finish-rolling to the steel pipe. COPYRIGHT: (C)2010,JPO&INPIT
|
