Heat transfer analysis and experimental study of unequal diameter twin-roll casting process for fabricating Cu/Al clad strips

Cu/Al复合板双辊异径铸轧复合过程传热分析与实验研究

Unequal diameter twin-roll casting(UDTRC)can improve the formability,surface conditions,and production efficiency during the fabrication of clad strips.Using Fluent software,a numerical simulation is used to study the asymmetric heat transfer characteristics of Cu/Al clad strips fabricated by UDTRC.The effects of roller velocity ratio,Cu strip thickness,and inclination angle on the kissing point position,as well as the entire temperature distribution are obtained.The heat transfer model is established,and the mechanism is discussed.The Cu strip and rollers are found to be the main causes of asymmetric heat transfer,indicating that the roller velocity ratio changes the liquid zone proportion in the molten pool.The Cu strip thickness determines the heat absorption capacity and the variations in thermal resistance between the molten Al and the big roller.The inclination angle of the small roller changes the cooling time of big roller to molten Al.Moreover,the microstructure of Al cladding under different roller velocity ratios is examined.The results show significant grain refinement caused by the shear strain along the thickness direction of Al cladding and the intense heat transfer at the moment of contact between the metal Al cladding and Cu strip.

双辊异径铸轧工艺可提高带材成形性能、表面质量和生产效率。基于Fluent软件对采用双辊异径铸轧工艺制备Cu/Al复合板过程中非对称传热特性进行数值模拟分析,得到辊速比、铜带厚度及倾角对凝固点位置和温度场的影响,建立传热模型,并探讨传热机理。结果表明铜带与铸轧辊是造成非对称传热的主要原因,其中辊速度比可改变熔池中液相区占比,铜带厚度决定了冷却速率及铝带和大铸轧辊间的热阻,小铸轧辊倾角影响熔融铝的冷却时间。此外,获得的不同辊速比时铝带的微观组织结构表明,沿铝带厚度方向剪切应变以及铝液与铜带接触瞬时强冷却使晶粒得到细化。