| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high strength linepipe which is inexpensively produced with high productivity without degrading collapse resistance and sour resistance, and to provide a method for producing the high strength linepipe. <P>SOLUTION: A high strength sour-resistant linepipe is a welded steel pipe which is obtained by forming a base material composed of a thick steel sheet into a tubular shape and joining the butted parts by welding the butted parts in two or more layers, and which contains, by mass, 0.02-0.08% of C, 0.01-0.50% of Si, 0.5-1.5% of Mn, a certain content of each of P, S, Al, Nb, Ca and O, and a certain amount of at least one selected from Cu, Ni, Cr and Mo, wherein Ceq is 0.30 or more, PHIC is 0.10 or less, ACR is 1.00-6.00, and the remainder comprises Fe and inevitable impurities. In the high strength sour-resistant linepipe, the metal structure and hardness of the surface layer part and the center part of pipe thickness are specified. The method for producing the linepipe is also provided. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
