5th International High Manganese Steel Conference - HMNS 2022

Hydrogen embrittlement of high strength steel is one of the critical issue when attempting to prolong the material life for a practical use. Because of this reason, macro/microstructural design for a prevention of hydrogen invasion is important to enhance hydrogen embrittlement resistance of materials. In is study, ultrasonic nanocrystalline surface modification (UNSM) treatment at elevated temperature was conducted to the high-Mn steel. Both ultrafine-grained layer and compressive residual stress at the surface region of the UNSM treated high-Mn steel not only provide an additional strength, but also prevent hydrogen invasion on the surface that reduces hydrogen localization. These beneficial effects enhance the mechanical property in a hydrogen-containing environment of the UNSM-treated high-Mn steel. Therefore, designing heterogeneous microstructure in high-strength steel can be a good strategy to improve both strength-ductility combination and prolonged life time in a hydrogen-rich environment.