Resistance HIC Characteristic and weld Characteristic with the hot rolling steel sheet and its production manner null for the resistance sour high-strength electric resistance welded steel tube

摘要

PPROBLEM TO BE SOLVED: To provide a hot rolled steel sheet for a sour resistant high strength electric resistance welded pipe having excellent HIC (Hydrogen Induced Cracking) resistance and weld zone toughness, and to provide a method for producing the same. PSOLUTION: The hot rolled steel sheet for a high strength electric resistance welded pipe is composed of prescribed components, and in which C, Si, Mn, Cu, Ni, Mo and V are comprised so as to satisfy the inequality (1), Ca, O and S are comprised so as to satisfy the following inequality (2), and Ca and S are comprised so as to satisfy the following inequality (3): Px=[C]+[Si]/30+[Mn]/20+[V]/10+[Cu]/20+[Ni]/60+[Mo]/7≤0.17 (1), 1.4≤Py=ä[Ca]-(130×[Ca]+0.18)×[O]}/(1.25×[S])≤3.4 (2), and Pz=[Ca]×[S]SP0.28/SP×10SP4/SP≤5.0 (3); wherein, [M] denotes the content (mass%) of the element M, further, the occupancy ratio of pearlite in the steel structure is ≤2 vol% (including 0 vol%), and the balance ferrite with the average crystal grain size of ≤10 μm. PCOPYRIGHT: (C)2007,JPO&INPIT