Ultrasonic Treatment to Molten FEM©™ Aluminum Alloy and Effects of Ultrasound Treatment Melt Temperature on Porosity

Abstract

Today, in the industry of aluminum, the D. C. casting of billets and slabs is playing the major role. The producers of these slabs and billets are many. The end users of the product are OEMs. The degassing technology for producing these aluminum slabs and billets is provided by very few. There are two types of degassing methods currently in use. One of these, vacuum degassing, is used primarily in the steel industry and thus not generally used in the aluminum industry. The second method, generally employed in the aluminum industry, is rotary degassing, which uses finely dispersed argon, chlorine, fluorine to remove dissolved hydrogen and various salts from melt. The challenges associated with producing aluminum are reducing porosity due to hydrogen precipitation during casting through degassing processes; which generates detrimental effects on mechanical properties of alloy castings and removing impurities like; the Ca, Mg salts etc. from the molten metal. Looking at the degassing systems provided by these players, are going to be obsolete as the environment norms will become stricter in the next decade, because of the use of Fluorine and Chlorine for removing the Ca, Mg, etc. impurities from the molten metal as the ozone layer is getting depleted and process becomes more cumbersome and hazardous. So, the innovation in the technology is needed; which leads research interest on development of the ultrasonic degassing as a better option. During this research authors would be using ultrasonic technology over existing technology to compare the results of conventional degasser units available in the market such as LARSTM, SNIFTM, STASTM - ACDTM, AlpurTM, MDUTM etc., and would be finding out the better operating parameters of ultrasonic equipment for the process for replacement of Fluorine and Chlorine based old technology with Ultrasonic Technology. This research paper should underpin improvement in the process and hence improved hardness of material by elimination of the fluorine and chlorine usage by replacing it with ultrasonic technology with suitable mechanical design, metallurgical criteria and thermal analysis consideration. During the entire research and development authors had carried out various operations like Research on thermal and metallurgical behavior of the molten metal and alloys, Comparison of results achieved using ultrasonic technique over existing technique, Formulation of conclusion; making ultrasonic technique a proven technology, and Identifying the further scope of research and development. With the experiments carried out, authors found significant improvement in hardness of the material produced by ultrasonic degassing as compared with the hardness of material produced by conventional degassing.