Effect of niobium on phase transformation and lamellar spacing of pearlites of high carbon steels during continuous cooling was studied on Gleeble 1500 thermo-mechanical simulator and microscopes. The results show that adding 0. 04wt% niobium to high carbon steels made CCT curves significantly move to the lower right and pearlite transformation temperature decrease. Niobium element had a double effect on nucleation growth rate of pearlite, which made average nucleation growth rate of pearlite kept constant and little changes of the interval width of transition temperature after adding niobium. Niobium could increase undercooling of high carbon steel, which could reduce lamellar spacing of pearlites.%通过Gleeble 1500型热模拟试验机和显微镜,研究了铌对高碳钢连续冷却过程中相变和珠光体片层间距的影响.结果表明:高碳钢中加入0.04％的铌后能使CCT曲线明显向右下方移动,降低了珠光体的相变温度；铌对珠光体晶核的长大速度具有双重影响,使得加入铌后珠光体晶核的平均长大速度不变,转变温度区间宽度变化不大；铌能通过增大高碳钢的过冷度来减小珠光体的片层间距.
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