The Korea Institute of Industrial Technology (KITECH) has developed smart welding technology that can manufacture fuel tanks, a key component of liquefied natural gas (LNG) ships, faster and more affordably.
The research team led by Ji Chang-wook at KITECH's smart process group noted that they developed the 'hybrid laser-arc welding' (HLAW) optimized for cryogenic special materials on the 25th.
LNG fuel tanks account for about 30-40% of the total construction expense of a vessel and require high-quality precision welding, leading to longer production times than other components. The arc welding method is mainly used in the production of LNG fuel tanks, which requires multiple repetitive welds for thick cryogenic special materials. This results in increased vessel production times and expenses.
The research team optimized HLAW, which combines the advantages of laser welding for precise joints and arc welding that can fill gaps or steps, for special materials such as 9% nickel steel. This success enabled the implementation of a single-pass welding method that quickly bonds without additional joint processing.
In particular, they successfully optimized the conditions for forming keyholes that deeply penetrate the material during welding, allowing curved or complex-shaped components to be robustly bonded with just single-pass welding. A keyhole serves as a passage for heat to be deeply transmitted into the material, enabling thick materials to be strongly joined with a single weld.
The research team also developed an AI-based process monitoring system capable of real-time quality detection and immediate response, implementing smart welding technology. The AI algorithm analyzes and differentiates ultraviolet (UV) and infrared (IR) signals occurring during welding, allowing operators to respond in real-time if defects are detected.
Ji Chang-wook, the lead researcher, said, 'We have established a smart welding process base that can shorten the time, expense, and defects of the cryogenic fuel tank welding process,' adding that 'we are currently promoting research to expand the developed technology to the production of tanks for eco-friendly ships that use hydrogen and ammonia as fuel.'