Effect of Pressure on Heat Transfer during Solidification of LM6 Aluminium Alloy in Squeeze casting process
* Principal, Erode Sengunthar Engineering College, Thudupathi,Erode-638 257.
** Assistant Professor in Mechanical Engineering, V.L.B.Janakiammal College of Engineering and Technology,Coimbatore-641 042.
Experiments have been conducted to determine the cause for the improvement in mechanical properties of squeeze cast LM6 Aluminium alloy. Investigations reveal that the interfacial thermal resistance between the cast metal and mould decreases with increase in squeeze pressure. As a consequence there is a marked decrease in solidification time and increase in tensile strength, ductility, yield strength and hardness.
Squeeze casting is a special casting process by which net or near net shaped components can be formed from the molten metal. It is a hybrid process of combining the features of forging and casting in one operation. The one step transformation of molten metal into highly shaped full density components is accomplished using a rigid die (mould). In this process a metered quantity of molten metal is poured into the female die (bottom half die) mounted on the lower platen of the press, and the upper die or punch is actuated. Closing of the die halves is accompanied by transmission of the press force through the punch on to the liquid metal. Not only does the sustained pressure during solidification eliminate shrinkage, it also ensures intimate contact between the metal and die, which accelerates solidification, improves metallurgical structure and promotes precision.
2. Literature Survey and Scope of the work
Many works have been carried out to obtain near net shaped castings and have been reported1-15 for metals like Aluminium, Copper etc. It has been found that the pressure applied during the solidification of metal improves the mechanical properties. Y.Nishida et al has...