A review on the hull structural steels for ships carrying liquefied gas: Materials performance subjected to low temperatures

Ensuring a higher level of safety during the transportation and handling of LNG (liquefied natural gas) fuel is critical. At a cryogenic temperature that can reach -163°C, LNG is stored in specialized Type-C independent tanks, and any accidental gas leak may cause damage to the ship's structure. Prolonged exposure to LNG flow may cause steel to become more brittle, and an accidental load on the ship's structure may result in structural collapse due to brittle fracture, leading to significant losses. As a mitigation measure against the risk of accidental LNG release on LNG-fueled ships, the use of higher strength and cryogenic temperature-resistant steel is necessary. This paper presents a discussion on the use of steel for shipbuilding, with a focus on the potential risks associated with accidental LNG release during transportation and the performance of steels subjected to low temperatures. Based on existing research, the discussion is organized into three topics, namely experiments conducted at cryogenic temperatures, including tensile tests and Charpy V-notch impact tests, and material modeling using finite element analysis. The paper provides a procedure and method regarding to these topics.