Being the stainless steel metal tubing for the oil well which the tube expander is done the stainless steel metal tubing for the oil well which

摘要

PROBLEM TO BE SOLVED: To provide a stainless steel pipe having superior pipe expandability and resistance to CO₂ for an oil well.;SOLUTION: The stainless steel pipe has a yield strength of 350 MPa or higher and an n-value of 0.08 or more, and has such a relation between the n-value and the uniform elongation u-El as to satisfy a relation: n0.007×(25-u-El), (wherein n represents an n-value; and u-El represents the uniform elongation (%)). Thereby, the steel pipe can secure the superior pipe expandability. The steel pipe has a composition containing, by mass%, 0.25% or less C, 1.0% or less Si and 0.10 to 2.50% Mn, P, S, Al and N in an appropriate amount, and 11.5 to 18.0% Cr; and has a structure including a tempered martensite phase as a main phase, and a 5% or more of austenite phase by a volume fraction as a second phase, or further a 5% or less of ferrite phase. In addition, the steel pipe can contain one or more groups among a group of Cu, a group of Ni, Mo, V and Nb, a group of Ti, Zr, B and W, and a group of Ca, as needed.;COPYRIGHT: (C)2009,JPO&INPIT