| 摘要 |
There is provided a steel pipe for fuel injection pipe that assures prolonged fatigue life and high reliability by securing a high critical internal pressure, at which fatigue fracture does not occur, while the material strength is high. A steel pipe for fuel injection pipe consisting of, by mass percent, C: 0.12 to 0.27%, Si: 0.05 to 0.40%, and Mn: 0.8 to 2.0%, the balance being Fe and impurities, the impurities containing Ca: 0.001% or less, P: 0.02% or less, and S: 0.01% or less, wherein the tensile strength thereof is not lower than 900 N/mm2, and the maximum diameter of a nonmetallic inclusion present during at least 20μm depth from the inner surface of the steel pipe is not larger than 20μm. Further, this steel pipe can contain one or more kinds of Cr: 1% or less, Mo: 1% or less, Ti: 0.04% or less, Nb: 0.04% or less, and V: 0.1% or less.
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