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借助热力模拟机Gleeble-3800得到了3个成分高碳钢的CCT曲线。采用金相显微镜、扫描电子显微镜、硬度计等研究了Nb含量对3种钢的CCT曲线、显微组织、马氏体分数、珠光体片层间距、珠光体硬度的影响规律。结果表明,Nb含量增加时,CCT曲线珠光体转变区向右下方移动,同样冷速下马氏体转变分数增加,出现贝氏体的冷速变小,但钢中含0.072%Nb的钢更有利于减少珠光体片层间距、提高珠光体硬度。同时,回归得到了珠光体片层间距模型,计算值与实测值吻合较好。
With the help of the thermodynamic simulator Gleeble-3800, CCT curves of three components of high carbon steel were obtained. The effects of Nb content on the CCT curves, microstructure, martensite fraction, pearlite lamellar spacing and pearlite hardness of the three kinds of steels were investigated by metallographic microscope, scanning electron microscope and hardness tester. The results show that when the content of Nb is increased, the transformation zone of the pearlite in the CCT curve moves to the lower right, the martensite transformation fraction increases at the same cooling rate, and the cooling rate of the bainite becomes smaller. However, the steel containing 0.072% Nb has more Benefit to reduce the pearlite sheet spacing, improve pearlite hardness. At the same time, the pearlite lamellar spacing model is obtained by regression, and the calculated value is in good agreement with the measured value.