The die casting process uses steel dies into which metal is forced under pressure through a runner and gate to fill the dies. The pressure (70 to 5000 kg/cm2) is maintained while the casting solidifies after which the dies are separated, cores are withdrawn and the casting is ejected.
Metals and alloys that are die cast include zinc, aluminium, and magnesium, copper, lead and tin.
Typical applications of die casting process include automobile components, household appliances, railway and aircraft fittings, bath room hardware, business machines, locks, pullers and many other similar parts.
Die Casting Dies:
The dies used for die casting resemble a permanent mould. They are generally made in two parts arranged to open and close with a vertical parting. When mounted on a die casting machine one of the die halves remains stationary during operation and is called a cover die.
The other half moves for opening and closing and is called the ejector die. Die casting dies are made of special die steels which are resistant to heat checking, hammering and mechanical wear and are also dimensionally stable. Die cavities are machined to very close accuracies. Vents and overflow wells are provided in the dies for escape of air. The dies may be water cooled to speed up cooling of the casting.
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