The roll is the core part of the mill, the roll type involves the use when using the selection, preparation, roll mill in the rolling process of the maintenance and periodic dressing, and these are all the factors affecting the productivity of the rolling mill, product quality and production efficiency. Because the rolling process is a continuous process, the operator needs to continuously detect the roll condition, so that the products can meet the requirements of the user for more stringent tolerances and surface quality. In order to keep the product competitive, it is necessary to continue to reduce the production cost of the rolling mill operators, that is, to improve the rolling speed, the production flexibility and reduce the consumption of the mill. So what should pay attention to roll surfacing?
(1) the fatigue layer or defect of the roller surface must be thoroughly cleaned before welding;
(2) in order to prevent the crack, it is necessary to process the roll body preheating firstly. The preheating temperature is determined according to the roll and the surfacing material;
(3) the key to success of surfacing welding, surfacing layer was the ideal must consider some variable factors, such as welding voltage, welding speed, roll speed, roll insulation, welding current, welding materials, some of the carbon and alloy elements in high roller core, in order to prevent the crack of brittle zone in addition, some measures of preheating, pre welding transition layer with low carbon low alloy transition layer.
(4) slow cooling and turning after roll surfacing. In order to reduce the volume and stress caused by the surface and internal cooling speed, the cooling rate should be controlled. Finally, the roll after the welding process, to restore the original size and finish.
And the performance of the surfacing roll:
(1) the service life of the roll after surfacing has been increased by more than one time;
(2) greatly reduces the cost per ton of steel, improve the production efficiency;
(3) the roll after welding has good crack resistance, wear resistance, cold and hot fatigue resistance.