Steel is often used because it is strong and hard. It is important for the socket former to be hard wearing as it needs to be able to mould the copper pipe whilst still maintaining its own shape.
Treated steels
The type of steel used for different parts can sometimes vary. The driver/ former can be made from hardened steel and the handle from high tensile steel. These are both types of steel that have been treated to increase the strength and durability of the product they are made in to.
Plastic
While most parts of socket formers are made from steel, some models include a plastic covered handle. This is simply an aesthetic addition.