Before we even get started with the guide, let us explain what forging means. Forging is a method by which metal is beat into a particular shape. The metal heats due to the constant blows delivered on it with a hammer to give it the required shape.
Now comes the part where we understand what open die forging is.
In the process of die forging a metal, the piece is placed on a stationary anvil, and with the help of a hammer, it is formed into shape.
Here are a few advantages of die Forging:
- In die Forging, there is a low chance of voids to be created.
- The metal comes out in fine grain size, and great at strength.
- It takes less time to work.
- Better microstructure, and a lot more.
Operations Involved in Die Forging
There are several operations involved in open die forging. Namely, upsetting, drawing out, piercing, cutting off, bending, forging, and riveting. We will go in-depth about these processes in the next segment.
Upsetting is the process through which the cross-section area of a metal bar increases at the expense of its length. The billet present between two flat surfaces of metal is squeezed to reduce its height. This reduction in height causes the cross-sectional area to increase.
The interface between the billet and die needs to be adequately lubricated. The lubrication is to produce the uniaxial compression uniformly.
In drawing out, the cross-sectional area of the metal bar reduces. This, in turn, increases the length of the bar. The workpiece placed between the two dies and forged successfully along the length. The entire process initiates in the middle, or from the sides and works its way to the middle.
A term called bite is used in this process. The bite is nothing but the length of the feed, before a stroke lands on it. The length of the bite can differ in the range of 40 to 75 percent.
Piercing or Punching
In the process of piercing or punching, blinds are made through holes in the billet. It involves forcing the punch to go through it. A short billet can be easily punched with holes, just by one stroke. One the other hand, if the diameter or the diameter to height ratio is large. The billet is placed directly on the die and punched with holes.
Cutting off the process is very self-explanatory. In this process, the metal piece or bar cuts off into separate parts using a tool like a chisel or forge cutter. The process involved two stages. The first stage involves a notch made with a chisel. And the second stage involves a chisel which is placed opposite to the notch.
Strikes made on the chisel by a sledgehammer cut the bar into pieces.
Bending is all about bending the metal piece into shapes like square, rings, links, or hooks. This entire process depends upon the use of the beak in an anvil. The metal bar held over the beak and strikes delivered to bend it into shape.
The inside layer of the metal bar in bending compresses. Whereas, the outer layer stretches.
Here, two metal bars join together to form a single piece. The bar is put under pressure and a suitable temperature to fuse.
We can also join two metal bars with the help of rivets and that process is called riveting. Open die forging is one of the most suitable methods to forge without using excessive energy. The pressure involved is less and the finer grains produced is high in quality.