Forging is a manufacturing process in which localized compressive force is used to shape the metal. Forging is one of the oldest metalworking processes.
The forging process involves plastic deformation of the metal between two dies to achieve the required configuration. Based upon the complexity of the parts, forging is carried out as closed die forging and open die forging.
Now, let us discuss the open die forging process and the closed die forging process.
In the open die forging process, the material is compressed by repeated blows using a mechanical hammer & metal is obtained in desired shape and size. In the closed die forging process, the required configuration is achieved by squeezing the workpiece between two shaped and closed dies.
Forging is the process in which loads are applied to the raw materials like the stresses produced being bigger than yield and less than ultimate so that the material is experiencing plastic deformation to get the desired shape.
In forging operation force applied can be either continuous or intermittent impact forces.
Table of Contents
Types of Forging
- Open Die Forging
- Closed Die Forging
- Cold Forging
- Roll Forging
- Rolled Ring Forging
- Upset Forging
- Isothermal Forging
- Multidirectional Forging
1. Open Die Forging
Open die forging, also known as drop forging, deforms the workpiece without completely enclosing the metal material within the die. Open forging is done by punching a workpiece into a mold until the workpiece is in the shape of a mold. Before being placed in an anvil-type process, the workpiece is heated and then forged to the desired shape.
2. Closed Die Forging
Closed die forging, also called impression forging, is a process in which the two halves of a die move towards each other to enclose a blank or billet. The heated workpiece is placed on the lower die and is approximately the same size as the part to be manufactured. The force provided by the encounter of the die compresses the workpiece to form the required forging. Although this process is initially more expensive than other forms of forging, the investment in precision, quality, and strength of the finished part pays off.
3. Cold Forging
Cold forging is a process in which metals deform and processes at room temperature or slightly above room temperature. The term ‘cold forging’ referred to drawing, heading, coining, punching, and thread rolling. The temperature of the metal is three-tenths of its recrystallization temperature. Cold forging is a very suitable technique for shaping soft metals such as aluminum and copper. Benefits of cold forming include reduced machining of the finished part, improved surface quality, improved dimensional stability, and reduced cost.
4. Roll Forging
Roll forging is a heated metal process in which opposing rolls are used to form and deform a workpiece. The shape and dimensions of the part are determined by the geometric shape to cut into the roll. Partially rotates the rolls while passing the workpiece between the rolls to create the part. The shape of the roll is 1/4 to 3/4 of both rolls. The grooves in the rollers give the workpiece a variable cross-section for secondary finishing.
5. Rolled Ring Forging
Rolling ring forging billets are removed before processing to generate a donut type or elliptical. It heats it so that it can work and simultaneously clicks between the rolls of threads and axial rolls that rotate at the same time. The billet is placed on the role of the thread and increases the diameter of the workpiece slowly against the driver’s rolls to make the wall thinner. The axial roller rotates in LECENENE and controls the width of the ring. When the process is complete, the rolling ring is a perfect oval for the production of gears, valves, clutches, and bearings.
The advantage of the rolling process has the ability to use strong components, fewer therapies, powerful grain patterns, and various materials. The diagram below shows an example of rolled ring forging.
6. Upset Forging
Upset forging, also called heading. This type of forging can be hot or cold. The workpiece is turned over at the end to increase the cross-section. It is usually performed on horizontal workpieces and is commonly used to make nails, screws, nuts, and bolts. Shaping the workpiece can be done with a punch or die. In some cases, both processes are used to achieve the desired shape.
The process steps in this cold forging example can be seen below. Here, the rod is fixed to the floor and is repeatedly struck with various dies to achieve the desired shape.
7. Isothermal Forging
The isothermal forging method uses a different approach to heating the workpiece. Some metals and alloys exhibit low-temperature malleability, which can make metal processing difficult. In isothermal forging, the workpiece is held at its highest temperature during the forging process. This is achieved by heating the die to a temperature equal to or slightly below the temperature of the workpiece. This method of forging eliminates contact with the mold and improves the performance of the final part.
8. Multidirectional Forging
Multidirectional forging is a time- and cost-saving hot forging process for producing complex and complex intricate parts. Mill-length steel bar is inserted into the forging machine at room temperature. When the rod enters the machine, it is overheated by an induction coil between 2000°F and 2400°F. It is then descaled from the bar, formed into a billet, and then entered into a forging mechanism. A precisely synchronized series of forming steps forms the blank. The finished part is then cooled and cold-formed.
It is completely formed in one step by punching the heated billet through the multi-directional forging, forming both horizontally and vertically.
Advantages of the Forging Process
The main advantages of the forging process are as follows.
- Equipment made using the forging process shows high ductility.
- Forging offers great resistance to impact and fatigue load.
- The forging process refines the structure of the material.
- It saves time, labor, and material cost.
- High precision can be acquired in the forging process.
- Forged material can be welded very easily.