Roll working principle

Resistance to thermal cracking
Usually the roughing rolls to strength, resistance to thermal cracking as the main requirements; small 20-roll mill work rolls weighing only 100 grams or so, while the support rolls of the wide plate mill has a weight of more than 200 tons. Selection of rolls, first of all, according to the basic strength requirements of the mill on the rolls, the main material selected for safe bearing (various levels of cast iron, cast steel or forged steel, etc.).

Finishing rolls and high speed, rolling the final product to have a certain surface quality, it is hardness, wear-resistant for the main requirements. Then consider the roll should be used when the wear resistance. As the roll wear mechanism is very complex, including the role of mechanical stress, rolling heat, cooling effect, the chemical effect of the lubricating medium, as well as other roles, there is no comprehensive assessment of the roll wear resistance of the unified index. As the hardness is easy to measure, and under certain conditions can reflect the wear resistance, so generally use the radial hardness curve to approximate the expression of the roll wear resistance index.
Impact resistance
In addition, there are some special requirements for rolls, such as large amounts of underpressure, the rolls are required to have a strong ability to bite, more impact resistance;

Rolling thin specification products, the rigidity of the roll, the uniformity of organizational properties, processing accuracy and surface finish requirements are more stringent;
Cutting performance
Rolling complex section of steel, but also consider the working layer of the roll body cutting performance.
Selection of rolls, some of the performance requirements of the rolls are often opposed to each other, roll purchase and maintenance costs are very expensive, so it should be fully weighed against the technical and economic advantages and disadvantages, decide to cast or forged, alloy or non-alloy, single material or composite materials.

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