Maraging-350 steel: Following the aging through diffractometric, magnetic and hyperfine analysis

• We report a fine characterization of aged Maraging-350 steel.
• Martensite shows a crystallographic distortion from the cubic symmetry.
• Reverted austenite is present in amounts that depend on the aging conditions.
• Properties measured are key information for a proper control of the steel aging.

Plates of solution annealed Maraging-350 steel were submitted to aging under an inert atmosphere, varying the time and temperature. The aged samples were characterized by X-ray diffraction and Mössbauer spectroscopy. The results revealed that the aging treatments induced the reversion of austenite, in amounts that vary with the time and the temperature of the heat treatment. The lattice parameters of the martensite and austenite phases, as well as their hyperfine parameters, were obtained at all aging conditions. No intermetallic compounds were identified in any of the aged samples, but a poorly crystallized phase fraction, the consequence of an incomplete martensite ⇒ austenite reversion transformation, was observed for some samples. The tetragonal distortion from cubic symmetry presented by the martensite in the solution annealed steel was not eliminated after aging.

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