Zr-4合金与模具钢的界面换热行为研究

Study on interfacial heat transfer behavior of Zr-4 alloy and die steel

摘要:

界面换热系数是锆合金塑性成形模拟的重要边界条件之一。本文测定了界面有、无玻璃润滑剂条件下Zr-4合金和H13模具钢的界面接触温度随接触时间的变化曲线,在此基础上分析了界面换热特征,获得了界面换热系数随初始界面温度变化的函数式。结果表明,玻璃润滑剂可有效减缓Zr-4合金与H13钢的界面传热,当Zr-4合金和H13钢的初始界面温度分别为700℃和470℃时,有玻璃润滑剂时Zr合金表面温度达到稳定的时间约为16.3s,该时间段内相应的界面换热系数随实验时间的延长由226 W/( m₂?℃)增大到2166 W/( m₂?℃),无润滑剂时Zr合金表面温度达到稳定的时间约为7.7s,该时间段内界面换热系数由250 W/( m₂?℃)增大到2700 W/( m₂?℃)。采用本文确定的换热系数随温度变化的关系式进行热交换模拟可以获得较高的模拟精度,模拟与实验结果的最大误差约为4.5%。

Abstract:

The interfacial heat transfer coefficient(IHTC)is one of the important boundary conditions for the simulation of the plastic forming of zirconium alloys. In this paper, the contact temperature-time curves between Zr-4 alloy and H13 die steel with glass lubrication and without glass lubrication were measured and the characteristics of the interface heat transfer were analyzed. The corresponding empirical formula between the interfacial heat transfer coefficient and the temperatures of both the Zr-4 alloy and die steel were established. The results show that glass lubricant can reduce the interfacial heat transfer between the Zr-4 alloy and the die steel effectively. When the initial temperatures of the Zr-4 alloy and the die steel are respectively 700℃ and 470℃, the temperature of the zirconium alloy surface tends to be stable at time of about 16.3s and the IHTC is increased from 226W/(m₂.℃) to 2166 W/(m₂.℃) during this time under the condition of glass lubrication, while the temperature of the zirconium alloy surface tends to be stable at time of about 7.7s and the IHTC is increased from 250 W/(m₂.℃) to 2700 W/(m₂.℃) during this time without glass lubrication. The empirical formula of IHTC obtained in this paper has high accuracy that the maximum error between the simulated and experimental results is about 4.7%.