基于热连轧精轧生产的纯钛TA1变形抗力模型研究

Deformation Resistance Model for Pure Titanium TA1 Based on the Hot Continuous Finish Rolling Process

为了研究某厂热连轧纯钛卷精轧段的变形抗力问题,根据工业生产的实际轧制工艺,确定该精轧段的轧件形变行为条件为:变形温度范围为700~800℃,应变速率为5~25 s^(-1),最大变形量为0.8,对纯钛进行热压缩试验。结果表明:纯钛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,变形机制受到温度和应变速率的影响较大,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。根据热模拟实验得到的真应力-应变数据,同时考虑化学成分的影响,基于Johnson-Cook模型建立了能够综合反映诸多因素的变形抗力模型,由变形抗力模型得到的轧制力计算值与实际值的比较验证了模型可靠性,为热连轧纯钛卷精轧生产的工艺控制提供了有效依据。

In order to study the deformation resistance problem of a pure titanium coil of the finishing rolling section of hot continuous rolling process, according to the actual rolling process of industrial production, a hot compression test on pure titanium was carried out in the following conditions： the deformation temperature range 700~800 ℃, the strain rate 5~25 s^-1, and the maximum deformation 0.8. The results show that the flow stress of pure titanium decreases with the increase of deformation temperature, while it increases with the increase of strain rate. The effect of temperature and strain rate on the deformation mechanism is obvious. The deformation is mainly dynamic recovery when the temperature is 700 ℃ 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 the most complete at the temperature of 800 ℃ and the strain rate of 20 s^-1, and its microstructure is the most homogeneous. According to the true stress-strain data obtained from thermal simulation experiments, as well as considering the influence of chemical composition, and based on the deformation resistance model of Johnson-Cook model, a deformation resistance model was developed, which can reflect many factors. Comparison of the calculated values of rolling force based on the deformation resistance model with the actual values could verify the reliability of the model. The model provides an effective basis for finishing rolling technical control of pure titanium coil in the hot continuous rolling process.