Microstructure and Properties of a Low Carbon Bainitic Steel Produced by Conventional and Inverted Two-Step Austempering Processes

The microstructure evolution and strain hardening behaviour of a low-carbon carbide-free bainitic steel prepared by either single-step austempering (420 °C or 365 °C), conventional two-step austempering (420 °C then 365 °C) or inverted two-step austempering (365 °C then 420 °C) treatments were investigated. The results show that when the total isothermal holding time was the same, the inverted two-step austempering treatment (first completing …