Cold Forging is a cold working process where the material is squeezed into a die and
the finished parts assume the shape of the die. This process is also known as Cold Heading.
Bar stock or wire stock is fed into a die and is squeezed into the closed die. The resultant part is a nail, a bolt or a screw with the head. A subsequent cold heading operation forms other features on the head such as knurls or slots for screw drivers etc. This process can be highly automated and parts can be made economically.
This method is used for both standard and special fasteners.
Advantages:- No heating required
- Better surface finish
- Superior dimensional control
- Better reproducibility and interchangeability
- Directional properties can be imparted into the metal
- Contamination problems are minimized
Disadvantages:- Higher forces are required
- Heavier and more powerful equipment and stronger tooling are required
- Metal is less ductile
- Metal surfaces must be clean and scale-free
- Intermediate anneals may be required to compensate for loss of ductility that accompanies strain hardening
- The imparted directional properties may be detrimental
- Undesirable residual stress may be produced