| 摘要 |
A stainless steel pipe for oil well use and a method for manufacturing the same are provided. A steel pipe is formed by performing pipe making of a raw material having a composition containing C: 0.05% or less, Si: 0.50% or less, Mn: 0.20% to 1.80%, P: 0.030% or less, S: 0.005% or less, Cr: 14.0% to 18.0%, Ni: 5.0% to 8.0%, Mo: 1.5% to 3.5%, Cu: 0.5% to 3.5%, Al: 0.10% or less, Nb: more than 0.20% and 0.50% or less, V: 0.20% or less, N: 0.15% or less, and O: 0.010% or less, on a percent by mass basis, wherein Cr + 0.65Ni + 0.6Mo + 0.55Cu - 20C ‰¥ 18.5 and Cr + Mo + 0.3Si - 43.3C - 0.4Mn - Ni - 0.3Cu - 9N ‰¤ 11 are satisfied and subjecting the resulting steel pipe to a quenching treatment to heat to a temperature higher than or equal to the A c3 transformation temperature and, subsequently, cool to a temperature of 100°C or lower at a cooling rate higher than or equal to the air cooling rate and a tempering treatment to temper at a temperature lower than or equal to the A c1 transformation temperature. In this regard, at least one selected from the group consisting of Ti, Zr, B, and W and at least one selected from the group consisting of REM, Ca, and Sn may be further contained. Consequently, a martensitic stainless steel pipe having excellent carbon dioxide-corrosion resistance in hot corrosive environments containing CO 2 and Cl - and excellent SSC resistance in environments further containing H 2 S and, in addition, having high strength of yield strength YS: 758 MPa or more can be produced with high producibility. |
