Casting (metalworking)

Casting iron in a sand mold.

In metalworking, casting is the act of pouring liquid metal in to a mold. When it hardens it is sometimes called a cast or casting.

Casting processes have been used for thousands of years. It is widely used for making sculptures, jewelry, weapons and tools.

Process

To cast iron, which is the most common material for casting, metal is first melted. It is then poured into a mold and let cool. After cooling, it may be grinded to become smooth, or hammered to become stronger.

Casting (metalworking) Media

Molten metal before casting
A hierarchy of casting processes, based on a similar work in Metal Casting By B. Ravi, p. 6.
Iron bell cooling after iron pour
Personal protective equipment to shield from radiant heat and molten splashes
An investment-cast valve cover
The permanent molding process
Intermediate cooling rates from melt result in a dendritic microstructure. Primary and secondary dendrites can be seen in this image.
Example of a cooling curve of a pure metal or eutectic alloy, with various aspects pointed out. Based on image from Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 0-471-65653-4.
The cooling curve and phase diagram of an alloy; in this case a copper/nickel alloy. Based on a diagram from Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 0-471-65653-4.