Abstract

Five quenching temperatures were designed to investigate the relationship between volume fraction of retained austenite and microstructure, mechanical properties of a medium carbon quenching and partitioning (Q&P) steel. It is normally accepted that the optimal mechanical property of Q&P steels is obtained by quenching at optimum temperature, which corresponds to the maximum amount of retained austenite. However, the present work clarified that maximum volume fraction of retained austenite in Q&P steels is indeed unrelated to the optimum mechanical property of steels. The microstructure consisting of coarse martensite laths, dispersive bainite and thin retained austenite films was obtained by quenching at fine martensite start temperature (FM_s), resulting in the optimum comprehensive mechanical property of Q&P steel with the better elongation at the expense of slightly smaller yield strength and tensile strength.

Graphic Abstract

中文翻译：

---

精细马氏体起始温度下的淬火和分区钢的优化性能

摘要

设计了五个淬火温度，以研究残余奥氏体的体积分数与中碳淬火和分隔（Q＆P）钢的显微组织，力学性能之间的关系。通常认为，Q＆P钢的最佳机械性能是通过在最佳温度下淬火来获得的，该温度对应于残余奥氏体的最大量。但是，目前的工作表明，Q＆P钢中残留奥氏体的最大体积分数确实与钢的最佳机械性能无关。通过在良好的马氏体起始温度（FM _s）下淬火，获得了由粗马氏体板条，分散贝氏体和薄薄的残留奥氏体膜组成的组织_。），从而使Q＆P钢具有最佳的综合机械性能，并具有更好的延伸率，但屈服强度和抗拉强度略有降低。

图形摘要