STEEL PLATE FOR PRESSURE VESSEL WITH EXCELLENT PWHT RESISTANCE AND MANUFACTURING METHOD THEREOF

A steel sheet for a pressure container for low temperature with excellent PWHT resistance and a manufacturing method thereof are provided. The steel sheet for a pressure container for low temperature with excellent PWHT resistance according to the present invention comprises, by weight%: 0.07 to 0.17% of C; 0.15 to 0.40% of Si; 0.3 to 0.7% of Mn; 0.012 or less of P; 0.015 or less of S; 3.0 to 4.0% of Ni; two or more kinds of elements selected from 0.03 to 0.025% of Nb, 0.03 to 0.12% of Mo, and 0.03 to 0.15% of Co; and the remainder including Fe and inevitable impurities, wherein a steel microstructure includes tempered bainite of 20 to 80 area% and the remainder of tempered martensite. PWHT 저항성이 우수한 저온용 압력용기용 강판 및 그 제조 방법이 제공된다. 본 발명은, 중량%로, C: 0.07 ~ 0.17%, Si: 0.15 ~ 0.40%, Mn: 0.3 ~ 0.7%, P: 0.012% 이하, S: 0.015%이하, Ni: 3.0 ~ 4.0%를 포함하고, 여기에 Nb: 0.03~ 0.025%, Mo: 0.03 ~ 0.12% 및 Co: 0.03~0.15% 중 선택된 2종 이상의 원소를 추가로 포함하고, 잔부 Fe 및 불가피한 불순물로 이루어지며, 강 미세조직이 20~80 면적%의 템퍼드 베이나이트와 잔부 템퍼드 마르텐사이트로 이루어진 PWHT 저항성이 우수한 저온용 압력용기 강판에 관한 것이다.