HIGH STRENGTH STEEL MATERIAL WITH EXCELLENT LOW-TEMPERATURE IMPACT PROPERTY AND A MANUFACTURING METHOD THEREOF TO REDUCE MANUFACTURING COSTS

摘要

PURPOSE: A high strength steel material with excellent low-temperature impact property and a manufacturing method thereof are provided to obtain a tensile strength of 500MPa or greater and a yield strength less than 80% by controlling chemical components and rolling conditions.;CONSTITUTION: A high strength steel material with excellent low-temperature impact property comprises 0.14-0.17 weight% of C, 0.30-0.40 weight% of Si, 1.25-1.35 weight% of Mn, 0.03 weight% or less of P, 0.015 weight% or less of S, 0.05-0.15 weight% of Ni, 0.15 weight% or less of Cr, 0.20 weight% or less of Cu, 0.04-0.06 weight% of V, 0 weight% of Ti, 0.012-0.017weight% of Al, 0 weight% of Nb, 0.008-0.012 weight% of N, and the remaining amount of Fe. The steel material has a tensile strength of 500MPa or greater, a yield strength less than 80%, and an impact value of 90J or greater at -5°C.;COPYRIGHT KIPO 2013;[Reference numerals] (AA) Temperature; (BB) Reheating; (CC) Rolling; (DD) Time