A Study on Bead on Plate (BOP) Test for Laser Welding Application of Stainless Steel to Liquified Hydrogen Tank (PART I: STS 304)

Abstract

Liquified hydrogen is considered a new energy resource to replace conventional fossil fuels due to environmental regulations by the IMO. When building tank for the storage and transportation of liquified hydrogen, materials need to withstand temperatures of -253°C, which is even lower than that of LNG (-163°C). These materials mainly include austenitic stainless steel and high-manganese steel, especially STS 304 steel mainly used to build liquified hydrogen tank. When building the tanks, both the base material and welding zone need to have excellent strength in cryogenic condition, however, manual arc welding has several issues due to prolonged exposure of the base material to high temperatures. Laser welding, which has some benefits like short period of exposure time and decrease of thermal affected zone, is used many industries. In this study, to determine the laser butt welding condition for STS 304 steel, laser bead on plate welding was conducted. After the BOP test, cross-section observation was conducted to analyze the penetration characteristics. After observation, four bead parameters were measured, and these tendency result of laser welding for STS 304 steel can be used as conditions laser butt welding of STS 304 steel.