STEEL MATERIAL FOR WELDING STEEL PIPE HAVING EXCELLENT LOW-TEMPERATURE TOUGHNESS, STEEL MATERIAL THAT HAS UNDERGONE WELD HEAT TREATMENT, AND METHOD FOR MANUFACTURING SAME

摘要

The present invention relates to a steel material to which post weld heat treatment (PWHT) is applied after pipe making and, more specifically, to a steel material that maintains excellent low-temperature toughness even after undergoing a PWHT process, a steel material which is obtained therefrom, and which has undergone PWHT, and a method for manufacturing the same.