Notably improved mechanical properties via introducing a short austempering treatment on low-carbon martensite steel

A novel process, quenching to a low temperature far below Ms followed by a short austempering treatment (Q-A-T), was carried out on a low-carbon martensite steel. Results show that a notably improved toughness without losing strength was obtained on the Q-A-T specimen as compared with the oil-quenched specimen. Microstructure analyses reveal that the Q-A-T specimen consisted of low-carbon martensite, high carbon-low temperature bainite and retained austenite. The fast quenching process effectively refined the martensite plate and the austempering process introduced the high strength phase-low temperature bainite, both of which are responsible for the improved mechanical properties.