03-10-2014, 10:32 AM
Abstracts: ? Metal casting is one of the most ancient techniques used for manufacturing metal parts. Metal casting is the process of forming metallic objects by melting metal, pouring it into the shaped cavity of a mold and allowing it to solidify. ? Solidified piece of metal which is taken out of the mold is known as a Casting. The process of casting involves the basic operations of pattern making, sand preparation, molding, melting of metal. Pouring in molds, cooling, heat treatment, finishing and inspection. ? There are lot many possibilities of defect occurs during casting process like Shrinkage, Porosity, Chills, Pipe defect, Microstructure defect, Scar, Blister, Scab, Cold shut, Outer sunks etc. From all that sdefects” Shrinkage” is the most crucial defect which directly affects the casting process. ? Grey cast iron expands upon solidification due to phase change then shrinkage as well as rough bubbles and void occurs in cast piece that directly affects the casting process. ? We suggest the solution to minimize the shrinkage defect is to use the exothermic compound like thermexo powder because in exothermic and insulating sleeves which are performed by the manufacturer and are placed in riser mold cavity to reheated the solidification time of the riser increase temperature and thus promote feeding.