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采用数值模拟方法,通过模拟板形灰铸铁件的消失模铸造充型过程,分析了各种工艺因素对充型过程中的气膜压力和气膜厚度的影响。结果表明,液态金属充型的驱动力并非重力而是消失模的退让速度,而这一速度是由气膜压力和气膜厚度的相互自动变化来调节,使充型达到稳态。结合理论计算,得到底注式浇注时充型可达到稳态,且气膜厚度和气膜压力随浇注温度、模样密度、涂料层厚度的增大而增大,随负压度和涂层透气性的增大而减小。
The numerical simulation method was adopted to simulate the filling process of the lost foam casting of the gray cast iron plate. The influence of various process factors on the pressure and the thickness of the gas film during filling was analyzed. The results show that the driving force of the liquid metal filling is not the gravitational but the retreating speed of the lost foam, which is regulated by the mutual automatic change of the gas film pressure and the gas film thickness so that the filling reaches the steady state. According to the theoretical calculation, the filling can be achieved at the bottom-pouring, and the film thickness and film pressure increase with the increase of pouring temperature, pattern density and coating thickness. With the negative pressure and the permeability of coating Increase and decrease.