Rolls in the rolling mill – How to prevent the danger of roll and improve the working efficiency
The operating conditions of the rolls in the rolling mill parts are the most messy. The residual stresses and thermal stresses occur in the preparation process before the roll is produced and used. When used, it is further subjected to various cyclical stress effects. How to prevent the hazard of the roll and improve the working efficiency is an important issue.
The operating conditions of the rolls in the rolling mill parts are the most messy. The residual stresses and thermal stresses occur in the preparation process before the roll is produced and used. When used, it is further subjected to a variety of cyclic stress effects, including twists, changes, shear, contact stress and thermal stress. The distribution of these stresses along the roll body is uneven and constantly changing. The reason for this is not only the planning elements but also the wear of the rolls, the constant temperature and roll shape changes. In addition, rolling conditions often exhibit abnormal conditions. The improper cooling of the roll after it is used will also be affected by thermal stress. Therefore, in addition to wear, the rolls often exhibit various damage such as cracks, cracks, falling off, indentations, and appearance damage. A good roll should have a good match between its strength, wear resistance and other various performance indicators. In this way, it is not only durable under normal rolling conditions, but also less damaging in the presence of certain abnormal rolling conditions. Therefore, it is necessary to strictly control the metallurgical quality of the roller or to supplement external measures to enhance the bearing capacity of the roller during the production of the roller. Reasonable roll shape, hole shape, deformation criteria and rolling conditions can also reduce the work load of the roll, prevent some of the peak stress, extend the roll life. The causes are related to the residual stress of the roll itself, the mechanical stress during rolling, and the thermal stress of the roll, especially when the temperature difference between the outer surface of the roll body and the core is large. This difference in temperature can be caused by poor roll cooling, cooling cessation or overheating of the roll surface at the beginning of a new rolling cycle. The infinite temperature difference between the outer surface of the roll and the core leads to a large thermal stress, which results in breaking of the roll when larger thermal stresses, mechanical stresses, and the residual stress of the roll exceed the core strength of the roll.
Cold welding repair method: The cold welding machine roller uses the electric spark high-frequency discharge principle to perform non-thermal surfacing on the metal surface, so it does not deform, anneal, undercut and residual stress during the repair of defects such as sand holes and scratches of the roller. , do not change the metal arrangement. High correction accuracy, coating thickness from a few micrometers to a few millimeters, can be applied to the metal workpieces wear, scratches, pinholes, cracks, defect deformation, hardness, trachoma, damage and other defects accumulation, sealing, repair and other corrections The utility model only needs to be polished and polished, and can also be subjected to various machining processes such as car milling, planing, grinding, and post-processing such as electroplating.