Numerical Simulation Of Temperature Field Of Squeeze Casting Of ZA27 Alloy With Large Ratio Of Height To Diameter

Squeeze cast is a cast technology near-net shape, it has significance for us to study squeeze cast technology to saving raw materials, decreasing energy consumed and improving quality of castings The Zn-Al alloy has many advantages, such as good mechanical property, strong antifriction property, processable property, affluent raw material, low cost and so on. But it has the liability to form shrinkage and segregation under the general casting condition. The squeezing casting of Zn-Al alloy merges the advantage of casting and forging and has the broad development. Up to now, for squeeze casting of ZA27 alloy with large ratio of height to diameter, there are lots of the shrinkage porosities in the castings. But this aspect is not researched;therefore, it is essential to carry out the research on the temperature field of squeeze casting of ZA27 alloy with large ratio of height to diameter in order to eliminate the shrinkage porosities in the castings.In this article, a software was programmed. The software was to simulate the temperature field of squeeze casting of ZA27 alloy with large ratio of height to diameter. During the simulation of temperature field, the method of equivalent specific heat was used to deal with the latent heat allowing for the broad crystallization temperature interval of ZA27 alloy as well as analyzing thermal diffusion coefficient of the liquid metal influenced by pressure. The analog results are validated by experience, and analog results are uniform with experiment results, which prove that the program may be used to research on the problem of squeeze casting with large ratio of height to diameter. The temperature distribution has been studied during solidification in the castings with large ratio of height to diameter is 6 by the methods of experiment and computer simulation. And the characteristic of shrinkage porosity distribution in the castings are also researched. The experimental and simulated results show that increasing the pouring temperature, or enhancing mold temperature cannot reduce the shrinkage porosities in the castings for squeeze casting with large ratio of height to diameter. And increasing squeezeforce is very difficult to eliminate the shrinkage porosities in the castings. When castings solidify as a sequence manner and squeeze force effectively acts on the surface of the liquid metal, the shrinkage porosities in the castings are eliminated and mechanical properties are increased obviously.Besides, as the example of squeeze casting of cup shell and syringe with large ratio of height to diameter, the temperature field of the castings were simulated and analyzed in order to improve technology process and increase the quality of the castings to a large extent.The problem of squeeze casting with large ratio of height to diameter is researched by simulating the temperature field, the way is scientific and can save time and cost. The results of research have important meaning for squeeze casting of the casting with large ratio of height to diameter.