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Cold bending process

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Almost every industry has a large amount of cold bending demand.
Steel and other metals can be formed in a variety of ways. Cold bending is one of the most common methods of shaping steel into many different configurations.

Hot and cold forming

Heat can be used for forming tube rolling to soften the metal and make the forming easier to bend.

Cold forming is also used for form-constrained rolling. Presses usually do not use heat to bend most of the soft, malleable metal around the shape.

Heat can also help free-form scrolling. Large diameter or thicker pipes are usually softened by heating when they are rolled through a free-form press. For example, heavy lead pipe or iron pipe needs some heat to bend. However, many times free-form rolling is cold-formed.
Sometimes, in the complex bends in free-form rolling, a mixture of the two is useful. A part of the tube is heated with a torch or hot air gun before being freely formed by cold pressing. The use of heat is at the discretion of the technicians and only used when the integrity of the pipeline is not compromised.

Cold bending process

The processing of cold-formed steel is actually carried out at room temperature. It is called cold bending to distinguish it from the hot bending process, in which the steel is heated by a torch or furnace before forming. This process usually uses rollers to press a piece of steel onto a metal forming tool called a mold. It can also be called cold rolling or pyramid rolling (such as metal profile bending using BIT series profile bending machines).

Benefits of cold bending

Cold bending does not require the use of fuel to heat the steel before processing, saving the extra time and effort of heating and then cooling the steel.

Cold rolling produces a smoother, smoother surface, and usually results in less deformation of the processed article.

An additional benefit is the increased strength when cold working steel.

When steel is manufactured at high temperatures and then cooled, it forms an internal crystal arrangement.

Processing steel at ambient temperatures below the crystallization point has been shown to increase strength at the molecular level by compressing and distorting the crystal structure. As the molecules get closer, they cannot move easily, so the steel becomes stronger.

Processing steel at high temperatures above the crystallization point means that crystallization will occur after processing the steel, so the steel will not be stronger than unprocessed steel. Heating steel that has been cold-formed or rolled will cause the material to lose the extra strengthening gained from the process, allowing the steel to regain its internal crystal structure.

The trade-off between the cold working process and the hot working process is that in exchange for the increase in cold working strength, the steel becomes more brittle, while the hot working steel generally maintains greater ductility. Heating steel that has been cold-formed or rolled will cause the material to lose the extra strengthening gained from the process, allowing the steel to regain its internal crystal structure.

Cold bending of different steel structures

Steel of any cross section and size can be cold-formed or rolled, as long as it can be fitted into existing molds and rolls.

Cold bending is most commonly used for pipes, channels, I-beams, angles and rectangular, round and semi-circular steel bars with a diameter less than 10 inches.

It is also possible to process large steel products, such as plates, but the size is limited due to the required force and the size of the rolling equipment required.

The bending process can be used to create gentle large-diameter curves, 90° angles, or long series of coils, where the pipe is continuously bent in a 360° circle.

Uses of cold-formed steel

Cold-formed steel has many uses.

Bending steel formed by cold bending is often used in the construction of buildings and bridges, and is especially impressive when exposed. Shipyards, railway and automobile manufacturers also use cold-formed steel products.

The petrochemical industry uses bent and coiled pipes to process and transport its products. Cold-formed steel has many other industrial and food processing applications.

Minimal deformation to form steel

Cold bending is an excellent method for forming steel with minimal deformation during the bending process.

Cold-formed steel can be used in a variety of applications from common daily necessities to high-tech professional industrial applications.