The line pipe which is produced making use of the steel and its steel which for the line pipe are superior in resistance HIC characteristic

摘要

As for the steel for the line pipe by this invention, constitution being similar mass %, C: 0.03 - 0.15%, Si: 0.05 - 1.0%, Mn: 0.5 - 1.8%, P: 0.015% or less, S: 0.004% or less, O: 0.01% or less, N: 0.007% or less, Sol.Al: 0.01 - 0.1%, Ti: 0.024% or less, Ca: 0.0003 - 0.02% is contained, the remainder consists of Fe and the impurity, in the steel the size of TiN which exists as a debris is 30 millimicrons or less. The steel for the line pipe by this invention is superior in resistance HIC characteristic, can hold down crack area ratio within 3%.