Open die forging uses multiple dies which do not completely enclose the material being forged. Items made through this type of forging often need extra work to finish to the required specifications.
Small quantity parts are where open die forging is used a lot, as well as simple parts such as cylinders or shafts. Due to the repeated working of the steel the strength of the grain structure will be increased therefore creating a stronger part.
The main feature of open die forging is its simplicity which also means the cost is low. Due to its low-cost open die forging can be used for bespoke one-off products. Less material waste is also created from the forging process therefore reducing the cost even more.
Some of the materials which can be open die forged include:
- Stainless steel
- Carbon steel
- Alloy steel
- Tool steel
There are drawbacks of using open die forging and one of these is the capability of producing high precision parts. Open die forging often requires extra machining to create high precision parts.
The alternative to open die forging is closed die forging. Two dies are used to form the piece into the required shape. The two dies are a negative image of the part being formed. As viewed from above pressure from the top die forms the raw material into the required shape.
Closed die forging is very economic for a large run of items and the parts produced require very little finishing.
Overall both types of forging have their advantages and disadvantages depending on the type of product you want produced. Low volume simple products are best suited to open die forging whereas higher volume more complex products are best suited to closed die forging.