| 摘要 |
PROBLEM TO BE SOLVED: To provide a method where heat treatment after tube making is simplified for producing a low-C martensitic stainless steel tube having high strength, and excellent toughness and corrosion resistance. SOLUTION: Steel containing, by mass, 0.01 to 0.1% C, 0.05 to 1.0% Si, 0.05 to 1.0% Mn, 9 to 15% Cr, 0.1 to 7.0% Ni, 0 to 5.0% Cu, 0.05 to 5.0% Mo, 0.0005 to 0.05% Al, and≤0.1% N is subjected to hot working into a seamless steel tube. In this case, the heating temperature of a billet is controlled to≤1,260°C, and, directly after finish rolling is performed in the temperature range of 850 to 1,150°C, or after reheating to the steel tube whose temperature is reduced after the finish rolling, cooling is performed at a cooling rate of≥25.0°C/min in the range of 800 to 600°C, and at a cooling rate of≤15°C/min in the range of 400 to 200°C. COPYRIGHT: (C)2003,JPO
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