| 摘要 |
PROBLEM TO BE SOLVED: To provide a long steel tube having an intermediate joined part excellent in low-temperature toughness and corrosion resistance by heating and joining only a tube material without through any welding material in the intermediate joined part of martensitic stainless steel tube mainly consisting of Cr of a specified weight ratio. SOLUTION: A stainless steel tube has the composition mainly consisting of, by weight, 7-15% Cr. Preferably, the chemical composition of the steel tube material has the composition consisting of 0.0005-0.050% C, <=1.0% Si, <=2.0% Mn, <=0.03% P, <=0.01% S, 7-15% Cr, 2.0-7.0% Ni, <=0.05% N, inevitable impurities, and, as necessary, selectively contains one or two or more kinds of elements of 0-3.0% Mo, 0-3.0% Cu, <=0.10% Al, and <=0.10% Ti, and the balance Fe. More preferably, an intermediate joined part is tempered at the temperature of Ac1 transformation point -100 deg.C to Ac1 transformation point +50 deg.C.
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