Influence of Austenitization Parameters on the Precipitation Sequence and the Chemical Homogenization of Austenite in a High-Performance Fe–Ni–Cr–Al–Ti–Mo Stainless Maraging Steel

MLX19 stainless maraging steel grade exhibits a mechanical strength/fracture toughness balance within the required range for landing gear applications. However, microstructure after heat treatment still needs to be precisely controlled obtain better repeatability of properties. This work shows that austenitizing is critical stage. The influence austenitization parameters on obtained quenching was thus quantified. It first revealed that, standard at 850 °C and specific heating rates holding times, undissolved β-NiAl precipitates, reaching sizes up 500 nm, remain in as-quenched state, addition high retained austenite fraction. also found large amounts are result local heterogeneities chemical composition austenitic phase prior quenching, while precipitates change overall matrix. New conditions were proposed, leading homogeneity martensitic matrix quenching.