2025 年 65 巻 2 号 p. 234-245
In this study, the solidification path and crack sensitivity of high‑manganese austenitic cryogenic steel (HMACS) were studied based on DSC and directional solidification experiments. DSC experiment explored the solidification mode with the result that the solidus of the steel is 1342°C and the liquidus is 1400°C. Subsequently, the relationship between solid fraction and temperature of HMACS was analyzed by DSC and directional solidification experiment with a pulling velocity of 5 µm/s. Based on this relationship, the brittleness temperature range of HMACS and its crack sensitivity were analyzed. The results suggest that the high crack sensitivity of HMACS is primarily due to its broad brittleness temperature range. Furthermore, according to the directional solidification experiments with different pulling velocities, the solidification cracks and microporosities of HMACS during the brittleness temperature range were also characterized and analyzed by using thermal stress calculations. All results express that the high crack sensitivity of HMACS is primarily due to its broad brittleness temperature range. This leads to the solidification structure experiencing a longer brittle period, resulting solidification cracks and microporosities defects during the liquid-to-solid transition.
