Fluidity characteristics of LM6/graphite particulate composite

Abstract

Casting processes involves flow of molten metal by a gating system and complete filling of mould cavity in order to accurately, faithfully reproduce all contours of mould. Molten metal is then poured onto mould at a particular temperature. This temperature immediately starts dropping when this molten metal enters the mould cavity and begins to flow. The main aim of such casting production is to create casting of excellent quality which carries all the intended details and contours from mould reproduced successfully on it. To accomplish such successful casting process, molten metal is required to possess certain casting characteristics like oxidation, fluidity, shrinkage, hot tear, gas absorption, etc. Amongst these characteristics, fluidity is considered to be an important parameter of molten metal.  The ability of molten metal to completely fill the mould cavity is called fluidity. It can also be considered as the ability of  molten metal to fill a given cross-section of the given mould. In simple terms, fluidity can be defined as mould filling capacity of molten metal.This fluidity is influenced by several parameters like pouring temperature of  molten metal, type of mould used for casting, nature of metal used, temperature of mould, coating used on mould surface, and treatment of molten metal such as grain refinement and modification. In fact, fluidity is a very complex parameter which cannot be precisely measured by any means. However, there are many methods available to qualitatively and quantitatively assess fluidity of molten metal. Therefore, it is imperative to determine fluidity of molten metal under a given set of conditions which will help the practical shop floor staff to obtain an understanding regarding the precautions and errors which must be taken to produce a successful good and efficient quality casting. In this project, attempts will be made to study the fluidity of LM6 (Aluminium 12% silicon) alloy and the composite prepared using graphite particulates in the LM6 base alloy, by pouring  molten metal into two different fluidity test moulds (i.e.: strip and spiral test). These moulds are standardised equipment’s which are being designed by considering several parameters which can have an influence on the flowing of molten metal within the mould channels. It is proposed to study effect of pouring temperature, moulding temperature, effect of mould coating material on the fluidity of metal.