30-08-2017, 03:30 PM
Casting is a manufacturing process for making complex shapes of metallic materials; during mass production, we can experience many defects, such as gas porosity, bolt holes, blow holes, shrinkage and incomplete filling which can occur in the sand casting. Porosity is one of the most frequent defects in ductile iron casting. Porosity affects the cost of scrap loss and limits the use of castings in critical high strength applications. The amount of porosity is closely related to the parameter of the sand casting process. The design of the gated / riser system plays a very important role in improving casting quality. Many researchers reported that 90% of defects in foundry are obtained only because of inadequate design of the food and feed system.