Rolling refers to the production of metal products and sections using different rollers. In this method, the metal passes through the rollers that rotate in the opposite direction and at the same speed, and the shape is changed.
what is rolling?
Rolling is basically a metalworking process that uses a lot of mechanical forces to change the shape and size of the metal. Usually, this process involves passing metals through a series of rollers that apply high compressive forces to the metal and cause it to change shape. In other words, the meaning of rolling is to enter metals into a rolling mill and make changes in its shape or size.
The rolling mill, which is also known as the rolling machine, consists of two or more rollers that rotate in the opposite direction and cause the metals to be pressed. This pressure changes the size and shape of the metal and makes it into your desired shape. In this process, metal may be converted into sheets, plates, rods, pipes or various structural sections that are used in industries such as construction, automotive, aerospace, manufacturing and infrastructure.
Introducing Types of Rolling
1- What is hot rolling?
As mentioned, hot rolling of steel is a process at a temperature higher than the crystallization temperature of the metal. In this method, the molten metal is passed through 2 rollers to reach the desired thickness. Since at a higher temperature, the flexibility of the piece increases and its molding becomes easier, this type of rolling requires less force.
hot rolling steps
To produce sections by rolling method, hot rolling must be done on it first. The steps of hot rolling are as follows:
Continuous ingot casting: In this step, the molten steel is poured into the mold and the ingot is produced.
Hot rolling: is one of the main stages of rolling, which reduces the thickness of the billet by using two large rollers and a repetitive movement.
Preheating furnace: In this stage, The temperature of the steel is raised to such an extent that it is only heated and not melted.
Final rolling: In the final rolling, the desired thickness is controlled and checked through the automatic system.
Cooling: The temperature of the metal is cooled using certain methods in a certain period of time.
2- What is cold rolling?
As mentioned, in cold rolling, the rolling operation is performed at a temperature lower than the recrystallization temperature of the metal. Since metals are less flexible at low temperature, in this method, hydraulic or pneumatic jacks are used to supply power. One of the most important advantages of this method is to make the surface uniform and remove the curvature.
Cold rolling steps
To perform cold rolling on sections, hot rolling is done on the billet first, then the primary product removed from hot rolling enters the process in the following order Cold rolling:
Acid washing: This is done in order to remove oxide scales.
Cold rolling: To further reduce In the thickness of the steel, it is passed through a cold rolling roller.
Heat treatment: This stage is also called annealing or annealing and it restores the metallurgical structure of the metal.
< b>Shell rolling: The last step is to wave the metal and create surface hardness.
Introducing Rolling Machine and its Types
Among the applications of the steel rolling machine, we can mention the shaping and production of parts, especially construction equipment and changing the thickness of metal sections.
The dimensions of the parts made by the steel rolling machine are determined and controlled by the rotation speed of the rolls and the distance between the rollers. This machine is used to produce sheets, ingots, as well as wire and wire in different sizes. In general, steel rolling machines are divided into 2 electromechanical and hydraulic categories. The components of the rolling line include the following: ✔️Rolling rack< br>✔️Rollers
✔️Bearings
✔️Bearing protection enclosure
✔️Moving force for moving rollers
✔️Mechanical and electrical equipment to control and adjust the force and rotational speed of rollers
Collection
Steel rolling is used to shape various parts such as beams, ribbed bars, plain bars, corners and studs. In fact, in the process of hot and cold rolling, a piece of metal is passed between 2 rollers and its thickness decreases due to the pressure applied by the rollers.