Development of a Lid Sealed furnace for the production of Magnesium alloys

Abstract

An atmosphere-controlled furnace was designed for the casting process of highly reactive Mg metal and its alloys. Instead of open crucible furnace, the melting process was done under controlled atmosphere which contained a mixture of low flow rate SF6 and CO2 gases. Furthermore, the application of salt flux was also eliminated. The melting process was carried out at 850°C for 15 minutes in a graphite crucible where Ca granulates were added as alloying elements. The molten alloy was manually stirred for 2-3 minutes before being poured into a stainless steel mould which was preheated at 450°C. Based on the experimental results, pore-free cast Mg alloy products were successfully produced through the utilization of the custom-made furnace and casting mould, coupled with proper stirring procedures. The Ca alloying elements were found homogenously distributed through out the Mg matrix. More importantly, the presence of the Ca alloying elements also had a significant effect on the grain size of the final cast product.