液态挤压过程凝固及热传导的模拟

液态挤压工艺是一步成形管、棒、型材的新开发工艺，本文在报道该工艺的基础上采用有限差分法对该工艺过程的温度变化及凝固过程进行了模拟，合理地解决了变形及并分网格变化的关系，使凝固过程中不同时刻，不同状态的温度场得到直观的显示，深化了对工艺本身的认识，为广泛研究该工艺及实际生产应用创造了条件。

SIMULATION OF THE SOLIDIFICATION AND HEAT TRANSFER OF THE LIQUID EXTRUSION PROCESS

Liquid extrusion process, which has been newly developed, can form tube, bar or shape products by only the single process. The process possesses the characteristics of the liquid metal forging and the solid extrusion, including crystallization under pressure, forced fedding, liquid-solid transformation, and plastic deformation so that it is a complex system. The temperature change and solidification process in fact is the key point to realize the process. For these reasons, the method and steps to simulate the temperature conduction and solidification of the process by using the finite difference method have been explored. The elements of workpiece, die, punch and mandrel have been partitioned. The difference equations and coefficient matrices for the typical elements have been given out. The latent heat is solved by the thermal compensation method. The change of the nets and the relevant temperature distribution resulted by deformation have been calculated by the spline surface interpolation method. According to simulation, the temperature change, liquid-solid transformation, solidification development in the whole process can be directly shown. The simulated temperature distribution and solidification states at different time have been given in the paper. So the research about the simulation is helpful for deep understanding of the process and it has provided a means for the extensive study and utilization in the practice.Correspondent: LI He jun, Professor, Faculty 401 of Northwestern Polytechnical University, Xi'an 710072