What is Cold Forging?

Also called cold forming, cold forging is a process that takes place near room temperature, rather than at higher temperatures like warm and hot forging. It’s done by placing the workpiece in-between two dies, and pounding the dies until the metal assumes their shape. Because of the friction created by the process, the temperature of the metal being forged can actually rise to 250° C or 482° F. Cold forging has its advantages and disadvantages. 

Advantages of Cold Forging

Because this process takes place without heating the metal beforehand, it provides many advantages and is often used in the automotive industry. For example, it’s often more economical than other processes, as the final product doesn’t require much finishing if any at all. There’s also little to no excess material left afterward, as the net weight of the original metal is about the same as the weight of the finished product. In addition to having no excess material, the dies used in cold forging last longer than in hotter processes, meaning fewer replacements. 

Another advantage is that although the ductility of the metal decreases during the cold forging process, the metal sees a great increase in both yield and tensile strength. Because it’s not heated, the grain of the metal retains its size and changes direction to match the change in the shape of the piece itself, resulting in this increased strength.

Disadvantages of Cold Forging

The main disadvantage of cold forging is that it can’t be used for every metal because certain types are much more likely to crack or break during the process. For example, while some steel can be forged at room temperature, steel types with a carbon content of .5% or above cannot. 

Another disadvantage is that cold forging can only create certain shapes. Those shapes are usually more basic and mass-produced. If you’re looking for a custom metal piece, a different process will probably work better for your desired outcome.