Cold Forging

What is Cold Forging?

Cold forging is a cost-effective and efficient metal deforming process for producing large quantities of parts. The result is a stronger and higher-quality product; however, cold forging should not be mistaken for machining or casting.

In the cold forging process, bar stock is put into a die and squeezed into a second closed die. The procedure is accomplished at room temperature or below the metal's austenite temperature to form the metal into the desired configuration.

How Cold Forging is Done

First, the workpiece is lubricated to keep it from sticking to the die and keep it cool during the forming process, which can reach temperatures of 482 to 842 °F (250 to 450 °C). Lubricants are not universally used and rely on the process of the company.

In the next step, the metal coil is fed into the forging machine through a die with the final part's shape.

One section of the die may be linked to the hammer and the other to the workpiece. The hammer is the striking mechanism that generates the force needed to distort the metal piece.

The striking of the workpiece, or stroke, can be accomplished using three mechanisms: hydraulic, pneumatic, and mechanical. Each technique uses a hammer to push a shaft onto the workpiece with considerable force to achieve the desired form. This occurs on a millisecond time scale.

The hammer may need to be dropped numerous times in a row to get the desired contour and shape. The next procedure is for removing the part and is determined by the process. Most modern producers employ a conveyor or a robotic hand to remove the item.

Another cost-cutting technique is to eliminate the necessity for material handling. This, like other components of the process, can take many different shapes. Then, the part is cut and shipped to shipping for pieces that only require one die and one stroke.

Parts with numerous aspects are carried on to different die operations to add features. In most cases, the transportation of the die from station to station is automated. Other mechanical means, such as a hi-lo, forklift, or crane, are utilized for larger pieces.

Cold Forging Equipment

The different types of cold forging equipment include:

Hydraulic Die Forming Hammer

It works based on hydraulics, in which an incompressible liquid is contained in a cylinder. A shaft with the die attached is forced down onto the workpiece when a piston pressurizes the liquid. It can make a variety of impressions using a variety of dies.

Pneumatic Power Press

The pneumatically driven press can perform a wide range of die pressing tasks. A pneumatically driven friction clutch and brake are included. The press is powered by an air compressor, which uses air pressure in a cylinder with a piston to propel the forging hammer down into the workpiece.

Types of Cold Forged Metals

The different types of cold-forged metals include:

• Copper is a great cold forging metal because it is ductile and malleable. It may be shaped, bent, or pushed with minimal force, generating corrosion- and rust-resistant parts.
• Carbon steel is an iron and carbon alloy. The amount of carbon combined with iron determines the various grades. It is extremely strong and flexible.
• Due to its corrosion resistance, look, and strength, stainless steel has become one of the most widely used metals. Stainless steel exists in several grades depending on the alloy content, while the word stainless steel is often used to denote any steel with its qualities.

Applications of Cold Forging

• Cold forging is particularly appealing to vehicle manufacturers because of its strength, durability, quality, and low cost. Because of their strong shock resistance, cold-forged parts are used in high-stress locations. Cold forged components include drive trains, drive shafts, and struts or shocks. The illustration below shows some pieces of a car's undercarriage that are made through cold forging.
• Due to its ability to eliminate the need for cutting in gear shaping, cold forging is employed in gear fabrication. Gears can be made from billets less than 50 mm in diameter or fashioned with coiled wire. To remove residual stress and work hardening, some annealing may be required. The smooth and quiet intermingling of cold-forged gears is a significant advantage.