Working conditions of rolls
Rolls according to the shape of the roll body is divided into cylindrical and non-cylindrical, the former is mainly used for plate, strip, profile and wire production, the latter is mainly used for pipe production. According to whether or not the contact roll is divided into work rolls and support rolls. Directly in contact with the rolls called work rolls; in order to increase the rigidity and strength of the work rolls placed on the back or side of the work rolls and not directly in contact with the rolls called support rolls. According to the use of racks are divided into initial rolls, roughing rolls, intermediate rolls and finishing rolls. According to the variety of rolling material is divided into strip rolls, rail beam rolls, wire rod rolls and pipe rolls and so on. Can also be rolled according to the state of rolling is divided into hot rolls and cold rolls.
Rolls in the mill components are more complex working conditions. Rolls in the manufacturing and use of the preparatory process before the production of residual stresses and thermal stresses. Use and further by the role of different cyclic stresses, including bending, torsion, shear, contact stress and thermal stress. The distribution of these stresses along the roll body is uneven, constantly changing, the reason is not only the design factors, but also in the use of roll wear, temperature and roll shape of the constant changes. In addition, rolling conditions are often abnormal. Rolls in the use of improper cooling, but also by the damage of thermal stress. Therefore, in addition to wear and tear, the rolls often have cracks, fractures, spalling, indentation and other local and surface damage. A good roll, its strength, wear resistance and other performance indicators should be a good match. So in the manufacture of rolls to strictly control the metallurgical quality of the rolls or supplemented by external measures to strengthen the bearing capacity of the rolls.