Quality Control Of Recycling Magnesium Alloy Ingot And The Casting Machine Design

Magnesium alloys, as a kind of structural material, have low specific weight, high specific strength, high specific rigidity, good electromagnetism shielding property, good casting capability and easy to recycling, et al. Consequently, Mg alloys have been widely used in auto, aviation, computing, 3C goods and hand-tooling industries. However, the recycling problem of Mg casting scrap becomes a great concern from the viewpoint of quantity die-casting scrap and normal recycling cost. The value of recycling Mg scrap is very huge economically and environmentally.Supported by Chongqing SinoST Co. Ltd., a series problems associated with the recycling of Mg scrap were studied in the present study. After a critical review of the fundamentals of physical chemistry properties of Mg, the western European classification of magnesium alloy scrap and the recycling technologies were elaborated. Then, the oxidation and ignition mechanisms of Mg alloys were studied from the viewpoint of oxidation thermodynamics and kinetics of Mg alloys at their processing temperatures. All these were used as theoretical principle while melting and casting. The resources of gas and impurity were studied and the refining theory was elaborated at the mean time. Heat transfer during ingot casting and the effects of pouring temperature, pouring rate and mould preheating temperature were studied. As a result, the ingot casting processing and its parameters were proposed.The effects of the key recycling parameters, such as, the Ar flow and refining time, the charging proportion of different recycled scraps on the chemistry and mechanical properties of the recycled Mg ingots were analyzed. Measurements for qualities control were suggested.To facilitate the ingot casting automatically, a short chain ingot casting machine is designed and manufactured to form a completed"on-site Mg scrap recycling system"with the recycling furnace of SinoST. The results of trial use of the machine show that the facility was successful, indicating that the facility can be commercialized as a product after optimization.