MANUFACTURING METHOD FOR VERY THICK STEEL PLATE AND CASTING SLAB FOR VERY THICK STEEL PLATE

摘要

The present invention relates to a method for manufacturing an ultra-thick steel sheet and a cast piece for an ultra-thick steel sheet. The method of manufacturing an ultra-thick steel sheet according to an embodiment of the present invention, in weight%, C: 0.02 to 0.2%, Mn: 1.0 to 3.0%, Si: 0.01 to 0.8%, Cu: 0.010 to 1.0%, Ni: 0.01 to 2.0%, Nb: 0.005 to 0.10%, V: 0.005 to 0.3%, Mo: 0.01 to 1.0%, Cr: 0.05 to 1.0%, Ti: 0.005 to 0.1%, Al: 0.005 to 0.2%, P: 0.02% or less , Preparing a steel material containing the balance iron (Fe) and inevitable impurities; Casting a steel material to produce a cast steel; And rough rolling the cast steel with a rolling reduction rate of 10% or more three or more times; including, casting a steel material to produce a cast steel; a rolling reduction rate of 1.5 to 4.5 mm/min during solidification of the steel material First rolling; And performing a second rolling at a reduction speed of 2 to 4.5 mm/min after solidification of the steel material.