Industrial Hardware

Forgings

Cold Forging

Cold forging occurs at room temperature and sometimes occurs by a process called impression die forging, or closed die forging. In some closed die forging techniques, the metal is placed into a die connected to an anvil. A hammer then hits the metal and forces it into the die, causing the metal to take on that shape. In another technique, the metal is heated slightly and placed in a die with a top and bottom impression. As the top and bottom impression come together, they compress the metal into the shape of the die. Cold forging is normally used to forge standard or carbon alloy steels.

Advantages of Cold Forging (aka Cold Heading)

Because no material is shaved off when forging alloys at room temperature, the amount of wasted alloy can be reduced to almost nothing. Also, since the alloy is shaped at room temperature, there is no need to heat the metal and thus saves the manufacturer money on heating costs.

Cold Heading Methods

There are several methods that can be used during cold heading. These vary based on the type of metal used and the intended final shape. The three most common methods are forward extrusion, backward extrusion and upset. Each is extremely important and having a unique purpose.

Forward Extrusion

This method reduces the diameter of the metal by forcing the metal to flow through a cavity with a smaller diameter than the piece. While the metal is forced through the cavity, extreme weight is used to compress the metal onto itself. Different metals have different compression yields. Softer metals like aluminum, tin and gold provide very favorable yield. Harder metals like steel and iron don’t have much compression, and thus don’t come out as thin when pushed through the cold heading machinery.

Backward Extrusion

During backward extrusion, holes are made and the material is allowed to flow around the cold heading item, which is used to create a penetrating punch. The penetrating punch pushes pieces of the metal through the created holes without cutting the metal out. A manufacturer might use a combination of the techniques in order to craft the metal into the desired shape. For example, a manufacturer might use backward extrusion to create a thin, shaped piece of metal. This can be used to make wiring or other circular material.

Upset

Upset forging deforms the metal under great pressure into high strength components, which can vary in size. This method is ideal for crafting pieces that only require one end to be forged, such as nails and bolts.

Tools Required for Cold Heading

Generally, in order to perform cold heading, manufacturers will use:

• Cold Header

• Part Former

• Punches

• Dies

Cold header and part formers both use horizontal reciprocating rams and stationary bolsters. A die is a type of mold that is the shape of the desired shape of the metal. A punch is a press that is sometimes powered by hydraulics that compresses the metal into the desired shape.

Warm and Hot Forging

In warm and hot forging, the metal is heated in a forge and then shaped into a final product. Warm and hot forging mostly use a process called open die forging, where there is a flat die and the metal is compressed and deformed at high temperatures into the desired shape. Open die forging can be used to make such parts as bars, blanks, rings, hollows or spindles, or any custom designed metal components. As the piece of metal is shaped after being heated, its internal grain deforms and follows the shape of the part. Consequentially, the grain is continuous, giving the piece improved strength. Forged parts are mostly used in machinery that requires high strength. Iron and steel are almost exclusively hot forged so that secondary machining operations on the piece are possible.

Types of Forged Products

Eyebolts

An eyebolt is a special type of fastener that resembles a lollipop. One end of the eyebolt resembles the threaded end of a screw, and the other side is forged into a circular shape. In a standard eyebolt, the shank (area of the bolt that isn’t threaded) of the bolt is centered below the mid-point of the circle.

Eyebolt Uses

Typically, an eyebolt is used to secure a cable, string, wire, or chain to some other object. For example, these bolts may be inserted into a ceiling or beam to support signs and heavy objects. An eyebolt installed in the floor can help support a hanging object and increase stability.

Eyebolts feature a forged construction. In a forged bolt, the eye at the top is made by bending a piece of steel to form a loop. 

Eyebolt Safety Precautions

When choosing an eyebolt, installers must find a unit that can safely support the required load. Generally, longer bolts and those with a thicker shank can support heavier weights. A large diameter eye can accommodate thicker objects like chains or heavy cables, while eyes with a smaller diameter can accommodate strings and thin wires.

An eyebolt is meant to be used at a 0 degree angle or a straight pull, meaning that it should be used perpendicular to the ground or ceiling. Although eyebolts can be used at greater angles up to 45 degrees, this lessens the load capacity significantly. If a user is unaware of this change, it can be dangerous to use. For example, a standard 5/8” shoulder eyebolt has a load capacity of 4000 pounds at 0 degrees. However, when the eyebolt is pulled at a 45 degree angle, the load capacity is only 1000 pounds. So while a user may think that the eyebolt can support the large weight that they need it for, it might actually be at risk of falling. Installing an eyebolt to support an angular load of more than 45 degrees is not recommended. Instead, users must use a swivel hoist ring that provides full 180 degree angular support for heavy weights.

Eyebolt Longevity

Many eyebolts are made of carbon steel, but like all steel objects, these bolts may rust or corrode over time. Bolts used outdoors should be made from galvanized steel to resist rust from rain and other forms of precipitation. If the eyebolt will be used around chemicals or in an industrial setting, stainless steel eyebolts will minimize the risk of corrosion and help the bolt hold up more effectively over time.