This article investigates the fracture behaviour of high-manganese austenitic steel subjected to welding thermal cycles, with emphasis on welding-induced microstructural changes and their influence on fatigue performance. The aim of this research was to identify the mechanisms responsible for microstructural degradation caused by welding thermal cycles and to assess their effect on fatigue crack initiation and propagation. Combined metallographic and fractographic analyses were applied to two variants of high-strength austenitic steel: laser-deposited cast weld metal and a wrought profile developed for lightweight structural applications. The comparative analysis provides insight into how processing history and welding-induced microstructural changes influence fracture mechanisms, strain hardening, and fatigue crack growth in high-Mn austenitic steels.

High-Mn austenitic steel, High-strength steel, Welding thermal cycle, Fatigue crack propagation, Strain hardening

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