Root cause analysis of furnace roll nodules
The root cause of the nodulation of the furnace rolls is: because the main speed roller is the tension roller outside the furnace at the outlet of the furnace, the speed roller is far away from the high temperature area in the furnace. The maximum load deviation between the furnace rolls in the high temperature area and the maximum load fluctuation of a single furnace roll are large, resulting in serious sliding friction between the strip and the furnace rolls. This causes the surface coating of the furnace roll to wear out, shedding a large number of particles, and forming nodules on the surface of the furnace roll.
measures to solve the problem
Regarding the main speed roller is the furnace outlet tension roller problem. It was originally designed by foreign suppliers, and there are many factors involved, which cannot be changed for the time being. However, it can be solved through the adjustment of process parameters. The maximum load deviation between the furnace rolls in the high temperature area and the maximum load fluctuation of a single furnace roll are both very large. This problem is not only related to the nodulation of the furnace rolls, but also related to the thermal buckling defect of the strip, which must be adjusted.
a) Adjust the tension distribution in the whole furnace to form a more reasonable tension gradient in the high temperature furnace area, reduce the furnace roll load from SF to SCS section, and reduce the friction between the strip and the furnace roll.
b) Adjust and optimize the uniformity of load distribution between furnace rolls within the same tension control zone. Prevent the surface of individual furnace rolls and strip steel from slipping due to uneven load distribution, and appropriately reduce the load of furnace rolls that are easy to cause nodules.
c) Adjust and optimize the load limit of a single furnace roll, so that the current load of all furnace rolls fluctuates within 5% to prevent the surface of the furnace roll and the strip from slipping due to the large fluctuation of the furnace roll load.
d) At the same time, the surface of the furnace roller is cleaned, and the roughness is ground to prevent the coating from wearing and falling off, and to minimize the generation of particles and impurities in the furnace.
By taking the above measures, the problem has been basically solved.