Roll selection

Selection of Rolls The work rolls of the small 20-high mill have a weight of only about 100 grams, while the weight of the support rolls of the wide-plate mill has exceeded 200 tons. When selecting rolls, firstly, according to the basic strength requirements of the rolling mill, the main material of the safety bearing (all grades of cast iron, cast steel or forged steel, etc.) is selected, and then the wear resistance of the rolls should be considered. Due to the complex wear mechanism of the rolls, including mechanical stress, thermal action during rolling, cooling, chemical action of the lubricating medium, and other effects, there is currently no uniform index for comprehensive evaluation of roll wear resistance. Since the 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 the roll.

Generally, the rough roll is mainly required for strength and heat crack resistance; while the finish roll speed is high, the final product of the roll must have a certain surface quality, and it is mainly required for hardness and wear resistance. In addition, there are some special requirements for the rolls. For example, when the amount of pressing is large, the rolls are required to have a strong bite-in ability and are more resistant to impact. When rolling a thin gauge product, the rigidity of the rolls, the uniformity of the structure properties, and the processing are performed. Accuracy and surface finish are more stringent; when rolling complex sections of steel, it is also necessary to consider the cutting performance of the working layer of the roll.

When using rolls, some performance requirements of the rolls are often opposite to each other. The roll purchase cost and maintenance cost are very expensive. Therefore, the technical and economic advantages and disadvantages should be fully weighed to determine whether to cast or forge, alloy or non-alloy. , single material or composite.