利用热模拟实验研究了一种含硼微合金钢未变形和900℃变形40%的奥氏体CCT曲线,利用光学显微镜和电镜研究冷却速度、变形对实验钢显微组织的影响。结果表明：微量硼提高实验钢过冷奥氏体的稳定性;未变形及变形试样分别在冷速2℃/s和5℃/s以上为贝氏体组织,变形提高贝氏体开始转变温度,但冷速在20℃/s以上时变形与未变形Bs温度相差较小;并且随冷速增加,显微硬度显著增加。
Continuous cooling transformation（CCT） curves of austenite in a low carbon steel containing boron without and with deformation of 40% at 900 ℃ were constructed by means of thermo mechanical simulation on a Gleeble-2000 simulator and Vickers hardness measurement.Influence of cooling rate and deformation process on the transformation behavior and microstructure of the steel was investigated by OM and TEM.The results show that the stability of undercooled austenite is enhanced by the addition of boron.Bainitic microstructure is formed with cooling rates from 2 ℃/s to 25 ℃/s and 5 ℃/s to 25 ℃/s in the steel without and with the deformation,respectively.Plastic deformation increases start temperature of bainitic transformation compared with that in undeformed austenite,however,the similar start temperature is observed when the cooling rates are over 20 ℃/s,and hardness of the steel increases with increasing of cooling rates.
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