铸嘴结构对3004铝合金铸轧流热场的影响及其优化设计

摘要

In view of the inferior liquidity of 3004 aluminum alloy melt in cast-rolling, difficult to distribute in feed tip nozzle and easy to cause defect of sheet, viscosity of 3004 aluminum alloy melt was measured by viscometer for high temperature melt, fluid-thermal field of melt in nozzle cavity was analyzed by finite element simulation analysis software (COMSOL Multiphysics) based on the actual physical parameters and production condition, and nozzle structure was optimized according to the simulation results and it was verified by experiment. The results show that the relationship between viscosityμand temperatureθfrom 660℃ to 750℃ can be expressed asμ=10−3×exp(0.059+621.379/θ). The vortex emerges in nozzle cavity and fluid-thermal field distributes unevenly at the output of nozzle when the angle is 8° between block and horizontal direction and the gap is 30 mm between block and spacers. While melts flow smoothly and fluid-thermal field is relatively uniform when the block is horizontal and the gap is 50 mm. The experiments show that the optimum proposal is feasible and the simulation results are accurate.%针对3004铝合金铸轧生产中熔体流动性差、铸嘴布流困难、易造成板面缺陷的现象，采用高温熔体黏度测量仪对3004铝合金熔体黏度进行测量，根据实测物理参数与生产工况，采用COMSOL Multiphysics软件对熔体在2种不同结构铸嘴中的流热场进行有限元模拟分析，根据模拟结果对铸嘴结构进行优化设计与实验检测。研究结果表明：在660~750℃范围内其黏度μ与温度θ的关系可表达为μ=10−3×exp(0.059+621.379/θ)；当铸嘴入口2边的挡块与水平方向成8°倾斜角，挡块与分流块间间距为30 mm时，铸嘴型腔内容易产生涡流，流热场分布不均匀；当铸嘴入口2边挡块水平设置，挡块与分流块间间距为50 mm时，熔体流动平缓，流热场分布较均匀。实验验证了模拟结果的准确性与优化方案的可行性。