Forging
Die Forging
In this method, a pre-measured amount of steel is heated until a cherry-red temperature is reached. This block of steel is placed in a two-part mold, which then closes under high pressure and forms the steel. The structural lines of the resulting material will follow the shape (as opposed to castings, which are amorphous), which benefits the mechanical properties of the product. Products that have to function under high loads are therefore often forged.
Forgings are comparable in cost or even cheaper than castings, but have the disadvantage of much wider tolerances, and many shapes are more difficult to forge than to cast, which in turn can lead to high machining costs. In addition, cutting the ordered structural lines during machining can negate the advantages of forging.
- High quality mechanical properties
- Wider tolerances
- Not every shape is suitable for forging
Press forging
During press forging, an amount of material is cut (usually soft materials such as copper or brass) and heated to a malleable temperature. This block is then shaped in one fell swoop by a hardened steel die. This is how brass couplings for the water pipes are made for example. It is a relatively inexpensive production process, depending on the material used. A drawback is that hollow shapes are not possible, and cavities must therefore be produced by machining afterwards.
- Relatively cheap
- Hollow shapes aren't possible
Free form forging
A finished block of steel is heated and placed on a hardened steel base plate. A mechanical hammer then strikes a certain place with a pre-calculated force. A skilled worker turns the workpiece with pliers, so that the blow ends up in the right location. This involves a lot of craftsmanship, and it is a fairly expensive method of production. It is therefore mainly used for small print runs, but is a rare production method nowadays.
- No mold needed, so well suited for small quantities
- Requires craftsmanship, time and money, and not suited for larger quantities
