Study On The Technique And Equipment Of Producing Protective Gas On-line For Magnesium

Magnesium alloys, as the lightest structural material at present , have many advantages, such as high specific strength, high specific rigidity, good casting capability and easy to recycle. As a result, magnesium alloys are named with "Green structural material of the 21th century", and have a huge potential in mass application in road vehicles, aircrafts, space shuttles, communication and electronic goods.However, there are some technical issues restricting the mass production and application of magnesium alloys, among which is oxidation and igniting of Mg alloys at high temperature. Therefore, anti-igniting becomes one of the pivotal techniques in magnesium alloys application. However, the research and development of anti-igniting techniques poor in China, even the anti-igniting technique and equipments are almost all relied on import. This situation is obviously adverse for the development of magnesium products in China. To tackle the igniting problem of Mg melt, this study is mainly devoted to the development of a new technique and equipment to produce Mg protective gas on-line and to replace mixed SF6 protective gas. To do so, this study starts with characterization of the magnesium oxidation and magnesia film, then studies igniting mechanism at high temperatures. Afterward the idea and technical details of producing protective gas on-line are illustrated, followed by design and construction of on-line protective gas generating system. Finally, the protective effects of on-line produced protective gas on AZ91D melt bath are examined systematically.In conclusion, The new technique and equipment of on-line generating protective gas can achieved effectively and reliably anti-igniting protection and can replace mixed SF6 protective gas. Furthermore the technique and equipment of on-line generating protective gas have some obvious advantages, such as cost, loss in melting, and durative of oxidation film.