STEEL PRODUCT FOR LINE PIPE EXCELLENT IN RESISTANCE TO HIC AND LINE PIPE PRODUCED BY USING THE STEEL PRODUCT

摘要

A steel product for a line pipe, which has a chemical composition, in mass %, that C: 0.03 to 0.15 %, Si: 0.05 to 1.0 %, Mn; 0.5 to 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 to 0.1 %, Ti: 0.024 % or less, Ca: 0.0003 to 0.02 %, and the balance: Fe and impurities, characterized in that TiN being present in the steel product as an inclusion has a size of 30 mum or less. The above steel product for a line pipe is so excellent in the resistance to HIC that it exhibits a cracked area ratio of 3 % or less in a HIC test specified in the specification.