A Comparison of Hot Cracking in GTAW and FCAW by Applying Alloy 625 Filler Materials of 9% Ni Steel

Recently, demand for LNG storage and fuel tanks has been increasing due to the International Maritime Organization(IMO) regulations on sulfur oxides and greenhouse gas emission. In the production of LNG tanks, 9% Ni steel is used and Alloy 625 or Hastelloy wire are used as the filler materials. In the FCAW welding process using Alloy 625 consumables, when using high current to increase productivity, hot cracking frequently occurs as well as welding defects such as lack of fusion due to arc instability. In this study, the hot cracking characteristics of FCAW and GTAW using Alloy 625 consumables in 9% Ni steel welding were compared through the FISCO hot cracking test. Key words: 9% Ni steel, Alloy 625, GTAW, FCAW, Hot crack