Rolls are classified in a variety of ways, and there are many factors to consider when choosing, the following is a specific introduction:
Classification of rolls
Sort by material
Cast iron roll: high carbon content, good wear resistance and corrosion resistance, relatively low cost, often used in some ordinary rolling occasions for precision requirements are not very high, such as the rough rolling process of small rolling mills.
Cast steel roll: good strength and toughness, can withstand greater rolling force, suitable for medium and large rolling mill rough rolling and middle rolling and other processes.
Forged steel roll: after forging process, dense structure, strength, toughness and wear resistance are very good, often used in cold rolling machine, high precision hot rolling mill and so on.
Composite roll: combined with the advantages of a variety of materials, the outer layer has high hardness, wear resistance, the core has good strength and toughness, suitable for high-speed, heavy load, high precision rolling production.
Classified by use
Strip rolling roll: including work roll and support roll, the work roll is directly in contact with the rolling piece, which plays a key role in the surface quality and dimensional accuracy of the strip; The support roll is used to support the work roll, improve the stiffness and stability of the work roll, and withstand the larger rolling force.
Steel rolling mill roll: according to the different shapes and sizes of rolled steel, designed into a variety of corresponding passes, such as I-steel, channel steel, Angle steel and other rolling mill rolls.
Tube rolling rolls: used for rolling pipes, divided into perforating rolls, tube rolling rolls, sizing rolls, etc. Different rolls play a role in different stages of tube rolling.
Wire rolling mill roll: usually has a small diameter and high speed, requiring the roll to have good wear resistance and surface quality to ensure the dimensional accuracy and surface finish of the wire.
Sorted by rolling temperature
Hot roll: used in hot rolling process, the working environment is high temperature, need to have good thermal stability, thermal fatigue performance and wear resistance, can maintain the dimensional accuracy and surface quality of the roll at high temperature.
Cold rolling roll: used in cold rolling process, the hardness, surface roughness and dimensional accuracy of the roll are very high requirements to ensure high precision and good surface quality of cold rolling products.
Precautions for roll selection
Properties of rolled materials
Material: If the rolling is alloy steel and other materials with high hardness, it is necessary to choose a roll with good hardness and wear resistance, such as carbide roll or high chromium cast iron roll; For soft materials, rolls with lower relative cost and better toughness can be selected.
Thickness and width: when rolling thick plate or wide plate, it is necessary to select a roll with large diameter and high stiffness to withstand the larger rolling force and ensure the flatness and dimensional accuracy of the plate; When rolling thin sheet or narrow strip steel, the surface precision and roughness of the roll are required to be higher.
Rolling process requirements
Rolling speed: When rolling at high speed, the roll needs to have good dynamic balance performance and thermal fatigue resistance to prevent vibration, wear and other problems in the process of high-speed rotation, you can choose forged steel roll or composite roll.
Rolling pass: For the process with more rolling passes, the wear resistance and fatigue resistance of the roll are required to be higher to ensure that the good performance is maintained during multiple rolling processes.
Mill types and specifications
Mill type: Different mill types have different roll requirements. For example, the work roll and support roll of the four-high mill have specific requirements in size and performance; The intermediate roll and the work roll of the six-high mill need to have different functions and performance characteristics.
Rolling mill specifications: large rolling mill needs to be equipped with large size, strong bearing capacity of the roll; Small rolling mill can choose smaller size, higher precision roll.
Production efficiency and cost
Production efficiency: In order to improve production efficiency, rolls with long service life and fewer roll changes can be selected, such as composite rolls, although the cost is higher, it can reduce the downtime of roll change time and improve the overall production efficiency.
Cost factors: It is necessary to comprehensively consider the procurement cost, use cost and maintenance cost of the roll. Under the premise of meeting the production requirements, choose the cost-effective roll.
