Abstract：In order to investigate the changing law of the volume percent of retained austenite in a medium-carbon bainitic steel under different isothermal conditions,X-ray diffraction measurement,thermalmechanical simulation experiment and scanning electron microscope were utilized to analyze the effects of austempering on the volume percent of retained austenite and microstructure. The results indicated that the final volume percent of retained austenite was affected by bainite and martensite transformation. The amount of bainite transformation influenced the amount and chemical stability of untransformed austenite,therefore affecting the amount of subsequent martensite transformation and the final volume percent of retained austenite. Moreover,the volume percent of retained austenite first increased with transformation temperature due to less bainite transformation (300-350 ℃) and then decreased because of more martensite transformation (350-400 ℃).
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2021, Vol. 56 
