Molten metal is poured into molds using different types of ladles, or in the production of high volume, automated pouring furnaces. Metal is poured into the “runners” (channel into the mold cavity) until the bush is complete runner. Provides the “riser” additional reservoir of metal feed to counteract the shrinkage that occurs as the casting begins to cool. When the metal has cooled enough to hold its shape solutions, it is separated from the mold by mechanical means or manual. If using sand molds, the process is often referred to as shakeout or knockout, and large amounts of dust generated.
A range of finishing processes are usually performed. These include:
♦ cleaning to remove residual sand, oxides and surface scale, often at or tumble shot blasting;
♦ heat treatment, including annealing, tempering, normalizing and quenching (in water or oil) to improve the mechanical properties;
♦ metal removing surface blemishes or over, (eg, flash lead to incomplete closure mold or burrs left from riser detached), grinding, sawing or arc air (oxy-propane cutting);
♦ correction of defects by welding;
♦ non destructive testing to check for defects;
♦ priming, painting or application of a rust preventive coating.
Recycling industry is a large amount of mold and core sand internally for reuse. The processing involves removing tramp metal and the sand returns to a condition that allows it to use again for mold or core production.