Cold rolling(also called cold roll forming) and hot rolling are two metal-forming processes used to produce metal sheets, strips, and coils.
Three differences between cold rolling and hot rolling
- Cold rolling is a process in which metal stock is passed through a pair of rolls under high pressure to reduce the thickness and increase the strength and hardness of the material. It is performed at room temperature, making it a “cold” process. The cold rolling process results in a strong, durable, and uniform product that is often used as a raw material for further processing.
- Hot rolling, on the other hand, is performed at elevated temperatures, typically above the recrystallization temperature of the metal. In hot rolling, the metal is heated to a temperature that makes it malleable, then passed through rolls to reduce its thickness. Unlike cold rolling, hot rolling does not involve the same level of pressure, and the resulting product is typically less dense and less uniform.
- Hot rolling is typically used to produce large-scale products, such as structural steel beams, plates, and pipes, while cold rolling is used for producing sheets, strips, and coils for a variety of industries, including construction, automotive, and consumer goods.
Six steps of the cold rolling process
Cold rolling is a metal forming process in which metal stock is passed through a pair of rolls under high pressure to reduce the thickness and increase the strength and hardness of the material. It is called “cold” rolling because the process is performed at room temperature, as opposed to hot rolling which is performed at elevated temperatures.
The cold rolling process typically involves the following steps:
- Annealing: The metal is heated to a temperature that makes it malleable, then cooled to room temperature. This makes it easier to roll the metal into thinner sheets.
- Cleaning: The surface of the metal is cleaned to remove any impurities or contaminants that might affect the rolling process.
- Rolling: The metal is passed through a set of rolls, which apply pressure to reduce its thickness and increase its strength and hardness. This process can be performed multiple times to achieve the desired thickness and properties.
- Tension leveling: The metal is stretched and straightened to eliminate any unevenness or waviness in the surface.
- Cutting and packaging: The rolled metal is cut to the desired length and packaged for shipment.
- Cold rolling is commonly used for producing sheets, strips, and coils for a variety of industries, including construction, automotive, and consumer goods. The process results in a strong, durable, and uniform product that is often used as a raw material for further processing, such as coating or stamping.
Cold rolling vs cold bending
- Cold rolling is a process in which metal stock is passed through a pair of rolls under high pressure to reduce the thickness and increase the strength and hardness of the material. It is performed at room temperature, making it a “cold” process. The cold rolling process results in a strong, durable, and uniform product that is often used as a raw material for further processing.
- Cold bending, on the other hand, is a process in which metal is bent into a desired profile/plate without being heated. This can be done using a press brake or other mechanical(such as plate rolling machine) means, and the bend is usually made at room temperature. Cold bending is often used to produce parts and components for various industries, including construction, automotive, and consumer goods.
- Cold rolling is typically used to produce sheets, strips, and coils, while cold bending is used to produce parts and components with specific shapes and dimensions.