Investigation of Low-Cycle Fatigue Properties of 316l Type Stainless Steel in a Full-Scale Large Liquefied Hydrogen Storage Tank

Abstract To achieve carbon neutrality by 2050, significant progress is being made in developing 50,000 m3 liquefied hydrogen storage tanks. One of the primary design challenges for these tanks is fatigue caused by repeated refilling cycles and seismic events. The influence of welding residual stress on fatigue performance is a critical factor that cannot be overlooked. Given the cryogenic conditions under which these tanks operate, full-scale testing is essential to ensure their safety and reliability. In this study, low-cycle fatigue (LCF) tests were conducted at an extremely low temperature of 20 K on 316L stainless steel specimens. These specimens were specifically designed to replicate the corner configurations of liquefied hydrogen (LH2) storage tanks and included two types of welds for comparison. The test amplitude was determined based on a Level 2 earthquake, representing a significant earthquake that could compromise the structural integrity of the tank. Following the LCF tests, fracture surfaces were analyzed in detail using a scanning electron microscope (SEM) to estimate crack lengths and propagation rates. The results of these observations provided critical insights into the safety of the storage tanks, demonstrating their ability to withstand the operational stresses and environmental conditions they are expected to face during their service life.