Development And Application Of Lost Foam Casting Simulation System Of Gray Cast Iron

As a near net forming technology, the lost foam casting(LFC) is taking an important place in the foundry due to its advantages of environment friendly style, high efficiency and high quality product. It has a wide application prospect. LFC production of gray cast iron is an important part in LFC application. However, in lost foam casting process of gray cast iron, the gas gap produced by decomposition and gasification of foam, have important influence on the filling and solidification, making the temperature field, flow field and pressure field of the whole process different from the traditional way of casting, making process control hard to realize. Therefore, this paper does research on the filling and solidification characteristics of LFC and focuses on development and application of lost foam casting simulation system of gray cast iron. The system can provide reference for technicians.First, mathematical model of lost foam casting is established in this paper. Through analysis of the existing interface shifting model and consideration of decomposition of the foam, the lost foam casting interface shifting model is realized by making the gas gap pressure as the boundary condition of the front metal flow. Based on computational fluid dynamics and numerical heat transfer, temperature model coupled with flow model of LFC is established. And the boundary conditions of the LFC simulation are discussed.Secondly, numerical calculation of LFC model is realized. Discrete equations of the lost foam casting model are solved by finite volume method, VOF method was used to capture the interface. And the numerical stability conditions of the LFC simulation are discussed.Then, thermos-physical parameters database for gray cast iron in LFC process is established. LFC solidification temperature experiment of grey cast ladder specimen is designed. The solidification temperature curve of six different points are analyzed and compared with the simulation temperature curves. Through the adjustment of single key factor, their influence on the solidification cooling curve is analyzed. A set of orthogonal experiment are designed to obtained physical parameters database for gray cast iron in LFC process, so that the simulation results and the actual temperature measurement data match each other.At last, LFC simulation system is developed based on InteCAST. And LFC simulations of gray cast iron specimen are implemented to study filling sequence and filling characteristics. Therefore, feasibility and reliability of the simulation system are proved. Then the simulation system is applied to simulate the casting process of LFC shell specimen and final distributions of casting defects of different technology schemes are analyzed. And the optimum casting parameters are determined. Thus, the feasibility of the simulation software and the mathematical model is verified. The software is capable of successfully simulating filling process and predicting defects distribution of LFC process, and providing design reference for the actual production quality control.