Manufacturing method of high tensile steel plate for line pipe with excellent cryogenic impact toughness and hydrogen organic cracking characteristics

摘要

The present invention relates to a method for producing a high-tensile steel sheet for large diameter line pipes used as an oil field and natural gas transportation means, the object of the present invention is to provide a method for producing a high-strength thick plate for line pipes having excellent impact toughness and hydrogen-organic cracking characteristics in cryogenic environments. In providing.;The present invention for achieving the above object by weight, C: 0.07-0.11%, Si: 0.20-0.30%, Mn: 1.00-1.30%, P: 0.020% or less, S: 0.003% or less, Cu: 0.10-0.30 %, Ni: 0.10-0.25%, Nb: 0.040-0.060%, V: 0.060-0.080%, Ti: 0.005-0.020%, Sol.-Al: 0.020-0.040%, remaining Fe and other unavoidable impurities, The technical gist of the present invention relates to a method for producing a high-strength thick plate for a line pipe having excellent cryogenic impact toughness and hydrogen organic crack resistance, which is formed by properly controlling and rolling a molten steel having a carbon equivalent (Ceq) of 0.262-0.379%.