MANUFACTURING METHOD OF WIDE AND THICK PLATE HAVING EXCELLENT STRENGTH AND TOUGHNESS FOR MAKING LINEPIPE

摘要

The present invention relates to a method for manufacturing a thick steel sheet for steel pipes used for the use of line pipes, and more particularly, to reduce the plate deformation after production and to be able to increase the manufacturable size of the steel sheet while being less constrained by equipment. It relates to a manufacturing method.;Method for producing a thick thick steel sheet of the present invention, C: 0.02 ~ 0.1%, Si: 0.1 ~ 0.4%, Mn: 1.3 ~ 1.8%, Sol. Al: 0.01 ~ 0.05%, Ti: 0.005 ~ 0.02%, Nb: 0.02 ~ 0.06%, V: 0.1% or less, Mo: 0.1% or less, P: 0.02% or less, S: 0.005% or less, balance Fe and other unavoidable Heating to a range of 1050 to 1150 ° C for steel slabs made of impurities; Manufacturing a steel sheet by finishing rolling at a reduction ratio of 70 to 80% at a temperature below the austenite recrystallization temperature; Cooling the steel sheet in a range of a cooling rate of 5 to 8 ° C./sec; And stopping cooling in a temperature range of 450 to 550 ° C.;Toughness, Strength, Thick Width, Plate Deformation