(1) Car L roller bearing damage caused. The 2nd cast rolls in the first roll 7. When ommX720mm casting board, the board is very good shape. When the reversing mill 7. ommX1060: when nm casting plate, the bearing housing has a very crisp sound. Because it is not to stop production immediately test machine, the production of three volumes on both sides of the casting plate with plate difference of 0.19mm. Total damage to the four bearings trial production period.
Low (2) roll cooling intensity or caused by uneven. Roll in use for some time, will bear the water tank is very thick scale, causing the roll cooling intensity is low, leaving the plate roll severely deformed shape is insufficient. Workshop at the beginning of production on the proposed tank cleaning problems within the roll, and for various reasons did not materialize. Until early 1996 due to the plate-shaped very unstable, resulting in a large number of unqualified products, fishes two rolls for the first time cleaning. After cleaning, the two sets of rollers with plate slab production deviations are below zero. lmm, and very stable. In the summer due to the cooling water pressure, water temperature can not reach the production process requirements, can also cause low roll cooling intensity, caused by uneven temperature difference with the panel exceeded.
Case (3) the bearing clearance in nozzle without damage, internal reasonable diversion, if the ends of the roll seam notes of the same, to produce the board should be the same thickness. But the fact is not the case, the same roll gap, out of the board thickness is a big difference. No. l roll up the maximum difference 0. lmm, the 2nd roll is up to 0.17mm. The reason is that the roller bearings on both ends of the gap is not the same, because when casting the role of the board caused by the rolling force is not the same at both ends of the roll gap, roll out the slab thickness is not the same. Once each for bearings, bearing clearance will change, causing great difficulties to the plate-shaped control.
(4) the thickness of the slab, the roll gap, roll crown of influence. Have a certain relationship slab casting cold-rolled strip thickness and roll gap, casting area, casting nozzle opening degree, casting temperature, cooling intensity, casting speed, etc., if the control is inappropriate, will cause flatness tolerance . Well, in the roll gap adjustment, the shift of production must also adjust the process parameters in order to make uniform the thickness of the board to obtain the desired flatness. Under normal circumstances, the roll gap and roll crown are in accordance with 7mm thick board set. If the casting nozzle opening degree, casting mayor, high temperature, low cooling intensity, the board thickness is greater than 7. smm, will inevitably result in excessive convex slab. Conversely, if the production of slab thickness of less than 6. smm, will result in concave boards.
