Az91 Magnesium Alloy Disappeared Casting Process

Expendable pattern casting (EPC) is the most promising one of the casting method, which has been known as the 21st century green production methods. Because of its unique technology and economic advantages, it has been adopted by more and more casting enterprises. Magnesium lost foam casting is a new technology in combination of advanced materials and advanced technology, which can play a series of advantages of magnesium alloys, but also of EPC technology. Therefore, it has important practical significance and applications to make lost foam casting of magnesium alloy technology.This paper can be divided into three parts: one is to study on fluidity of expendable pattern casting of AZ91 magnesium alloy; second is the microstructure of AZ 91magnesium alloy cast before heat treatment; Third part is the analysis for the lost foam casting of magnesium alloy casting defects found in the experiment.Firstly, the influence of the process parameters and pouring system (including pouring temperature, metal static head, pattern thickness, vacuum degree, open angle) on mold filling in magnesium alloy by EPC process was studied. The results indicate that the magnesium alloy EPC process must use vacuum, which can improve the fluidity dramatically. Increasing pouring temperature can also significantly improve the fluidity of AZ91 magnesium alloy. After using vacuum increasing pouring temperature can increase the mobility of magnesium alloy AZ91. The thicker the pattern is,the better fluidity of magnesium alloy is. About pattern shape, the mobility of magnesium alloys enhanced with the bigger of the opening angle of the pattern. Secondly, the microstructure of AZ91 magnesium alloy has been observed that it has strong effect of wall thickness which is that the thinner the pattern the smaller the tissue. Vacuum can significantly refine the microstructure of magnesium alloy, and the higher vacuum is, the smaller the tissue. Finally, casting defects emergence in some experiments has been analyzed, and some solutions can be used.