METHOD TO MANUFACTURE STEEL MATERIAL WITH EXCELLENT LOW HEAT INPUT WELDING CRACK RESISTANCE AND HIGH HEAT INPUT HEAT AFFECTED ZONE TOUGHNESS, AND STEEL MATERIAL WITH EXCELLENT LOW HEAT INPUT WELDING CRACK RESISTANCE AND HIGH HEAT INPUT HEAT AFFECTED ZONE TOUGHNESS MANUFACTURED THEREBY

摘要

The present invention relates to a method to manufacture a steel material with excellent low heat input welding crack resistance and high heat input heat affected zone toughness, and a steel material with excellent low heat input welding crack resistance and high heat input heat affected zone toughness manufactured thereby. According to the present invention, the steel material comprises: 0.06 to 0.12 weight percent of C; 1.25 to 1.70 weight percent of Mn; 0.03 to 0.33 weight percent of Si; greater than 0 to 0.012 weight percent or less of P; greater than 0 to 0.005 weight percent or less of S; greater than 0 to 0.20 weight percent or less of Cr; greater than 0 to 0.85 weight percent or less of Ni; 0.015 to 0.05 weight percent of Sol-Al; 0.05 to 0.35 weight percent of Cu; 0.01 to 0.35 weight percent of Nb; greater than 0 to 0.01 weight percent or less of V; 0.007 to 0.023 weight percent of Ti; greater than 0 to 0.006 weight percent or less of N; greater than 0 to 0.0005 weight percent or less of B; and the balance of Fe and inevitable impurities. Moreover, a welding crack sensitivity index (Pcm) satisfies 0.13 to 0.26 and Ceq(IIW) satisfies 0.28 to 0.52, such that excellent low heat input welding crack resistance and high heat input heat affected zone toughness are excellent, thereby providing characteristics suitable for manufacturing an icebreaker used in a cold extreme environment.;COPYRIGHT KIPO 2019