The work roll of small 20-high mill only weighs about 100g, but the weight of the back-up roll of wide and heavy plate mill has exceeded 200t. According to the basic strength requirement of the rolling mill, the main material of safety bearing is selected, such as cast iron, cast steel or forged steel, etc. .
     Folding hardness and high speed finishing roll, rolling the final product to have a certain surface quality, to its hardness, wear-resistant and so on as the main requirements. Then consider the roll when the use of wear resistance should be.
     Because the wear mechanism of roller is very complicated, including mechanical stress, heat effect, cooling effect, chemical effect of lubricating medium and other effects, there is not a unified index to evaluate the wear resistance of roller.
     Because hardness is easy to measure and can reflect the wear resistance under certain conditions, the radial hardness curve is generally used to approximate the wear resistance index of roller.
     In addition, there are some special requirements for the folding impact resistance of the rolls, such as: When the reduction is large, the rolls are required to have a strong biting ability and to be more impact resistant; The requirements of rigidity, uniformity of microstructure and properties, machining accuracy and Surface finish are strict, and the cutting properties of the working layer of the roll body should be taken into account when folding cutting properties are used to roll the section steel with complex section.
     When the roller is selected, some performance requirements of the roller are often opposite to each other, and the purchase and maintenance cost of the roller are very expensive. Therefore, the advantages and disadvantages of the technology and economy should be fully weighed and the casting or forging should be used, alloy or non-alloy, single or composite. Roll hardness,roll technology,three roll