退火温度对Nb-Ti微合金冷轧板再结晶行为的影响

Effect of annealing temperature on recrystallization behavior of Nb-Ti microalloyed cold rolled steel sheet

采用硬度法和金相法相结合对Nb—rri微合金冷轧板的再结晶行为进行了研究，同时研究了退火温度对其显微组织和硬度的影响，并讨论了（Nb，Ti）C粒子对再结晶过程的影响。结果表明，退火温度低于625℃时，冷轧板只发生回复，硬度有稍许下降。当温度高于625℃，等轴晶开始出现，随着退火温度的升高，再结晶晶粒不断增多，硬度迅速下降，在675—700℃硬度出现平台，750℃时获得全部再结晶组织。再结晶温度为710℃，弥散分布的纳米尺寸（Nb，Ti）C粒子推迟了再结晶的过程，提高了再结晶温度。

Recrystallization behavior of Nb-Ti microalloyed cold rolled steel sheet was investigated based on the hardness testing and metallographic method, meanwhile, the effect of annealing temperature on the microstructure and hardness was studied, and the effect of （Nb,Ti） C particles on recrystallization process was also discussed. The results show that, when the annealing temperature is below 625 ℃, the Nb-Ti cold roiled steel sheet recoveres only with a slight decrease in hardness. However, when the annealing temperature is higher than 625 ℃, the recrystallized equiaxed grain begins to appear, and its amount gradually increases with temperature increasing, but the hardness decreases rapidly. The hardness has a small platform between 675 ℃ and 700 ℃. Full recrystallization microstructure happens at 750 ℃. The recrystallization temperature is 710 ℃. The dispersive distributed nano size （Nb, Ti）C particles postpone the recrystallization which results in the recrystallization temperature increase.