1.6 GPa级中碳高强贝氏体钢残余奥氏体调控机理

 为了研究中碳高强贝氏体钢中的残余奥氏体体积分数在不同等温情况下的变化规律,通过X射线衍射试验、热模拟试验和扫描电子显微镜观察等,分析了等温淬火条件对中碳高强贝氏体钢中残余奥氏体体积分数和组织的影响。结果表明,最终残余奥氏体的体积分数受贝氏体相变和马氏体相变的共同影响。贝氏体相变量决定了未转变奥氏体的体积分数及其化学稳定性,从而影响随后的马氏体相变量及最终残余奥氏体体积分数。此外,随着相变温度的升高,开始由于贝氏体相变量逐渐减少,残余奥氏体体积分数先增加(300~350 ℃),随后由于马氏体相变量增加,残余奥氏体体积分数减少(350~400 ℃)。

Controlling mechanism of retained austenite in a 1.6 GPa grade medium-carbon high-strength bainitic steel

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℃).