低合金高强钢连续冷却微观组织转变研究

Study on Microstructure Transformation of Low Alloy High Strength Steel in Continuous Cooling

通过热膨胀法测定了低合金高强钢CCT曲线并分析了其微观组织的变化,结果表明,实验钢在3～50℃/s冷却范围内,均可得到贝氏体组织,当冷却速度为30℃/s以上时还会出现部分马氏体组织。随着冷却速度的提高,贝氏体开始相变温度和转变结束温度相应降低,显微组织逐渐由粒状贝氏体向板条贝氏体转变,且相变组织越加细小。

This paper studies the microstructure transformation by thermal expansion method based on the high strength low alloy steel. The results show that the bainite structure can be got when the cooling rate is 3-50 ℃/s. When the cooling rate is above 30 ℃/s,part of martensite can be got. With the increase of cooling rate,the bainite start temperature and finish temperature is correspondingly reduced with cooling rate increase. The microstructure gradually transformed from the granular bainite to lath bainite, and the microstructure is very fine.