Centrifugal rolls for steel rolling production can be manufactured by forging, casting, powder sintering, and other methods. Hot-rolled work rolls are mainly cast rolls. In the past, the drum was not a composite structure, but a single material. To make the centrifugal roll have high performance, the roll has been developed into a composite structure roll with a high degree of freedom in the outer material. The casting methods of composite rolls mainly include centrifugal casting and continuous casting. The inner layer of the centrifugal roll is ductile iron, and the inner layer of the continuous-casting composite roll is cast steel.
Cold-rolled work rolls are mainly forged rolls. Cast and forged rolls are made from a variety of materials. According to the data, adopt the corresponding roller manufacturing method. After rolling, the surface properties of the rolls change due to wear. At this time, the deteriorated layer on the surface of the roller can be removed by grinding and other methods, and the roller can continue to be used.
Centrifugal roll performance requirements:
The strip hot rolling mill is divided into a rough rolling section and a finishing rolling section. The decoration part is divided into a front section and a back section. Since hot rolling is carried out at high temperatures, it is required that the roll has wear resistance at high temperatures. Therefore, the main material of the centrifugal roll is a casting material containing a large number of carbides. The rolling load and heat load of the thick cross-section roll are relatively large, and the roll material should be a casting material containing a large number of carbides. However, starting from the finish rolling, the material of each vertical roll can be changed to a material with a lower carbide content.
Generally, the centrifugal roll using cemented carbide is a roll with a composite structure. The outer layer of the drum is made of hard material so that the outer layer of the drum is the wear-resistant and anti-orange peel. The inner layer of the roller is made of tough material, so the roller will not break due to torque and deceleration force. In rough rolling, due to its high reduction rate, large rolling load, and high rolling temperature, materials with high strength and good heat resistance are selected. Finishing rolls are made of materials with good wear resistance and orange peel resistance.
The development direction of the centrifugal roll
The front roll of the finishing mill emphasizes wear resistance and orange peel resistance. To improve the wear resistance of high-alloy rolls, alloy elements such as V are added to the steel, and high-hardness cemented carbide MC is used to improve wear resistance. The roll is a modified high alloy roll. The C content of high-alloy rolls and improved high-alloy rolls is about 3%, so the carbides in improved high-alloy rolls are mainly cementite except for MC. In addition, the improved centrifugal roll structure contains a few percent of the graphite area ratio, which can smooth the thermal bonding of the steel plate in the event of a rolling accident.
