| 摘要 |
<p>A steel pipe as fuel injection pipe of 500 N/mm2 or higher tensile strength composed of, by mass, 0.12 to 0.27% C, 0.05 to 0.40% Si, 0.8 to 2.0% Mn and the balance Fe and impurities, the contents of Ca, P and S in the impurities being 0.001% or less, 0.02% or less and 0.01% or less, respectively, characterized in that the maximum diameter of nonmetallic inclusions present in at least the region extending from the inside surface of the steel pipe to a depth of 20 mum is 20 mum or less. Further, there is provided a steel pipe as fuel injection pipe which is identical with the above except that at least one member selected from among 1% or less Cr, 1% or less Mo, 0.04% or less Ti, 0.04% or less Nb and 0.1% or less V is further added thereto. These steel pipes as fuel injection pipes realize a high material strength, high limit internal pressure free from fatigue breakdown, prolonged fatigue life and high reliability. ® KIPO & WIPO 2009</p> |
