Steel pipe without sewing thick wall of low -strength low -alloy resilience for tubular petroleum products

摘要

"A seamless, thick, low -resistant steel tube for tubular petroleum products." Is a seamless, thick, low -grade high -resistibility steel tube for tubular petroleum products that has excellentResistance to SSc. The steel tube of the present invention is a steel pipe without low -strength thick wall seam for tubular petroleum products that has a 40 -millimeter or more wall thickness and a 758 -mpa elasticity limit or moreWhere the steel tube includes a composition that contains,In terms of%in mass,C: 0,25 to 0,31%,Si: 0,01 to 0,35%,Mn: 0,55 to 0,70%,P: 0010% or less,S: 0001% or less,0: 00015% or less,AI: 0015 to 0040%,Ass: 0,02 to 0,09%,Cr: 0,8 to 1,5%,Mo: 0,9 to 1,6%,V: 0,04 to 0,10%,NB: 0005 to 0,05%,B: 00015 to 00030%,Ti: 0005 to 0020%,And N: 0005% or less,And which has you /n from 3,0 to 4,0,The balance is faith and unavoidable impurities,Where a cumulative frequency rate at a measuring point at which a degree of Mo segregation by a predetermined expression is 1,5 or more is 1% or less,And the steel tube has 60,7 /o,4 of 1,02 or less in the voltage -deformation curve.