MACHINE-INDUCED PHASE-TRANSFORMATION IN A MARAGING-STEEL

Phase transformation, i.e. martensite to austenite (alpha-gamma) reversion, is detected in grade 350 maraging steel as a result of machining processes. The thermal stability of machine-induced austenite is found to be higher than that of the thermally produced austenite. The machined samples, when ausaged with and without prior solution annealing, exhibit different amounts of austenite formation at same ausaging temperatures. The austenite start temperature for machined samples is found to be lower than for the unmachined samples. Texture measurements of machine-induced and thermally produced austenites are also reported.