| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hot-rolled steel sheet for an oil well pipe and a method for manufacturing the same, which can manufacture an oil well pipe that exhibits sufficiently low level of defectiveness in the ultrasonic testing (UT). <P>SOLUTION: The hot-rolled steel sheet for an oil well pipe includes, by mass, at least: 0.15% or more and less than 0.30% C; 0.10-0.40% Si; 1.0-2.0% Mn; 0.01-0.10% Al; 0.0015-0.0050% Ca; 0.005% or less S; 0.0050% or less N; mass ratio of Ti to N (Ti/N) satisfying 3.2 or more; and the balance with a steel composition of Fe and inevitable impurities. The hot-rolled steel sheet for an oil well pipe has a sheet thickness of 10 mm or less. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
