| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of seamless steel tube for a boiler and its piping, which does not cause a rolling defect on a product, even when a Mannesmann type skew rolling process is adopted. SOLUTION: A material consisting of C:≤0.15 mass%, Mn:0.30-0.60 mass%, Si:0.20-1.0 mass%, Cr:8.0-10.0 mass%, Mo:0.85-1.10 mass%, P:≤0.030 mass%, S:≤0.030 mass% and Fe and inevitable impurities as the balance is formed into a seamless steel tube by a Mannesmann type rolling process composed of various rolling mills. In the process, during rolling at each rolling mill, the material is rolled adjusting a strain rate of the material to a value within a designated range corresponding to a rolling temperature of the rolling mill. COPYRIGHT: (C)2005,JPO&NCIPI
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