纯钛高温变形行为及其在精轧板中的应用

Hot deformation behavior of pure titanium and its application in hot sheet finish rolling

在温度为700~800℃、应变速率为1~20 s^(-1)、变形程度为60%的变形条件下,对纯钛TA1的高温热变形行为进行热模拟试验研究。以真应力-真应变热模拟试验数据为基础分别建立真应变为0.3和0.6时的热加工图,以确定较佳的热轧温度区域;基于J-C模型建立变形抗力模型并进行验证。研究结果表明:纯钛TA1的流变应力随变形温度升高而降低,随应变速率升高而升高,变形机制受温度和应变速率的影响较大;当温度为700℃、应变速率为1 s^(-1)时,主要以动态回复为主,随着温度和应变速率的增加,动态再结晶程度不断增加;当温度为800℃、应变速率为20 s^(-1)时,再结晶比较充分,组织均匀性良好。利用该变形抗力模型并有效控制轧制温度区间,能够达到较好的轧制效果,轧后钛板性能满足国标要求。

The hot deformation behaviors of pure titanium TA1 were studied by thermal simulation experiment with deformation temperature of 700-800 ℃, strain rate of 1-20 s^-1, and deformation degree of 60%. According to the true stress-true strain data obtained from thermal simulation experiment, the processing maps at strain of 0.3 and 0.6 were established to determine the optimum hot rolling temperature region, respectively, and a deformation resistance model based on the J-C model was developed and verified. The results show that the flow stress of TA1 decreases with the increase of the deformation temperature, while increases with the increase of the strain rate. The temperature and strain rate affect the deformation mechanism greatly. The deformation is mainly dynamic recovery when the temperature is700 ℃ and the strain rate is 1 s^-1. The degree of dynamic recrystallization increases continuously with the increase of temperature and strain rate. The dynamic recrystallization is well-completed at the temperature of 800 ℃ and the strain rate of 20 s^-1, whose microstructure is homogeneous. The rolling effect is better using the deformation resistance model and controlling the temperature region effectively, and the rolled pure titanium sheet can meet the requirements of the national standard.