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How to prevent the harm of rollers and improve work efficiency?
时间：2023-05-25 14:03
来源： network
The working conditions of the rollers in the rolling mill components are relatively chaotic. Residual stress and thermal stress may occur during the preparation process before production and use of the roller. During application, it is further subjected to various cyclic stresses, including twists and turns, modifications, shear forces, contact stresses, and thermal stresses. The distribution of these stresses along the roll body is uneven and constantly changing, not only due to planning elements, but also to the continuous changes in wear, temperature, and roll shape during the use of the roll. In addition, rolling conditions often exhibit abnormal conditions. Improper cooling of the roller after use can also cause harm from thermal stress. So in addition to wear and tear, the rollers often exhibit various damages such as cracks, cracking, detachment, and indentation, as well as external damage. A good roller should have a good match between its strength, wear resistance, and various other performance indicators. This not only ensures durability under normal rolling conditions, but also minimizes damage in certain abnormal rolling conditions. So when making rolls, it is necessary to strictly control the metallurgical quality of the rolls or supplement it with external measures to enhance the load-bearing capacity of the rolls. Reasonable roll shape, pass, deformation criteria, and rolling conditions can also reduce the working load of the rolls, prevent partial peak stress, and extend the roll life. The cause of occurrence is related to the residual stress of the roller itself, the mechanical stress during rolling, and the thermal stress of the roller. It occurs more easily when the temperature difference between the outer surface and the core of the roller body is large. This temperature difference can be caused by poor roll cooling, suspension of cooling, or overheating of the roll surface at the beginning of a new rolling cycle. The infinite temperature difference between the outer surface and the core of the roller results in significant thermal stress. When the significant thermal stress, mechanical stress, and residual stress of the roller exceed the strength of the core of the roller, it causes the roller to break.
Cold welding repair method: The cold welding roller uses the principle of high-frequency electric spark discharge to carry out heatless surfacing welding on the metal surface, so that it does not deform, anneal, bite or residual stress during the repair of defects such as sand holes and scratches on the roller, and does not change the metal arrangement. High correction accuracy, coating thickness ranging from a few micrometers to a few millimeters, can stack, seal, and repair defects such as wear, scratches, pinholes, cracks, defects, deformation, hardness reduction, sand holes, and damage in metal workpieces. It only needs to be polished and polished, and can also be used for various mechanical processing such as turning, milling, planing, grinding, as well as post processing such as electroplating.
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