The working conditions of the roll in the rolling mill are the most complicated. The residual stress and thermal stress will occur in the preparatory process before the roller is made and used. The effect of various periodic stresses is further affected by the application, including twists and turns, changes, shear force, contact stress and thermal stress. The stress distribution along the roller body is uneven, constantly changing, the reason is not only the planning elements, as well as the use of roller wear, temperature and roll shape changes. In addition, the rolling conditions often show abnormal conditions. After cooling, the roller is not used properly, and it will also be affected by thermal stress. Therefore, in addition to wear roller, but also often crack, cracking, shedding, indentation and other parts of the damage and surface damage. A good roll, its strength, wear resistance and other performance indicators should have a better match. In this way, it is not only used in the normal rolling condition, but also can be damaged in some abnormal rolling condition. Therefore, in order to enhance the bearing capacity of the roller, it is necessary to strictly control the metallurgical quality of the roll or with external measures. Reasonable roll shape, hole, deformation criterion and rolling conditions can reduce the roll work load, to prevent part of peak stress, extending the life of roller. The reason is related to the residual stress, the mechanical stress and the thermal stress of the roller, especially when the temperature and the temperature of the core are larger. This temperature difference can be caused by poor roll cooling, cooling off or overheating at the beginning of the new rolling cycle. The temperature difference between the outer surface of the roll and the core leads to a large thermal stress, which leads to the breaking of the roller when the thermal stress, mechanical stress and residual stress of the roller exceed the strength of the core.
Cold welding repair method: cold roll welding machine is the use of electric spark discharge principle of metal surface without thermal surfacing, so in the repair of defects such as trachoma, roll scratch during deformation, annealing, undercut and residual stress, the metal does not change the arrangement. High precision correction, coating thickness from several microns to several millimeters, shortcomings can appear wear, scratches, pinhole, crack, deformation, defects, hardness decreased trachoma, damage to the metal workpiece stacking, sealing and reinforcing peer revision function, by grinding and polishing, but also cars, milling, planing, milling etc. all kinds of mechanical processing, electroplating and post processing.