METHOD FOR PRODUCING THICK STEEL PLATE HAVING EXCELLENT WELDED ZONE TOUGHNESS AND DUCTILITY AND WELD STRUCTURE USING THE SAME MATHOD

摘要

PURPOSE: A manufacturing method of thick steel plate having the excellent toughness and ductility of welded part and a welded structure using the same are provided to have excellent toughness and ductility of SAW (Submerged Arc Welding) welded part, in which the component of base material is diluted during welding process, by controlling the rolling and cooling condition. CONSTITUTION: A manufacturing method of thick steel plate having the excellent toughness and ductility of welded part comprises the following steps of: heating a steel material at 1000 to 1250°C; completing the finishing rolling of heated steel material over the ferrite transformation initial temperature (Ar3); and cooling the rolled steel material at temperature over the Ar3. The steel material includes carbon of 0.06 to 0.14 wt%, manganese of 1.0 to 1.6 wt%, silicone of 0.1 to 0.5 wt%, niobium of 0.005 to 0.06 wt%, and phosphorus of 0.008 to 0.03 wt%. The steel material cp is satisfied with 0.38 to 0.64, and remaining part consists of iron (Fe) and the other unavoidable impurities. [Reference numerals] (AA) Welded part ductility (J); (BB) Ductility; (CC) Scope of the request for Cp; (DD) Elongation percentage; (EE) Elongation percentage (%)