热浸镀铝提拉速度与镀层厚度的关系

Pulling Speed and Coating Thickness for Coating of Hot Dip Aluminizing

热浸镀铝是一种高效的金属表面防护方法,虽然目前已经有了一定的生产规模,但鲜有关于对热浸铝过程的数学模型的研究报道。本文研究了镀层厚度与提拉速度及凝固时间的关系,建立了相关数学模型,采用Q235钢片,溶剂法热浸镀铝,设定铝熔体净化温度为730℃,浸镀温度为690℃,浸镀时间为3 min,使用无级变速提升机控制钢片提升速度等进行实验验证。实验结果表明,当提升速度低于0.12 m/s时镀层厚度与提拉速度的平方根成正比,与凝固时间成线性关系,与本文建立的数学模型结果非常吻合。

Hot dip aluminizing is one of the effective surface protection methods for steels. It is being gradually putinto use ina certain scale,while there are few documents on the mathematical model for hot dip process of aluminizing. In this paper,to describe the correlation among the coating thickness,pulling speed and solidificationtime of the coating,the mathematical models were established according to Navier-Stokes equation and heat transfer principle. And experiments were carried out to validate the models. In the experiments,the pure aluminummelt was purified at the temperature of 730益. Cook-Norteman method was used in pretreatment. The temperatureof molten aluminum was set to 690益 and the dipping time was set to 3min. A direct current motor with steplessspeed variation was used to adjust the pulling speed. The results indicate that the coating thickness is proportionalto the square root of pulling speed,for the Q235 steel plate,and that there is a linear relationship between coating thickness and solidification time when the speed is lower than 0.12m/s. The results are in good agreement withwhat the theoretical models predict.