Causes and countermeasures of local high point of wear-resistant plate
The local high point refers to the phenomenon that the thickness of the wear-resistant plate at this point on the cross section of the wear-resistant plate is thicker than that in the adjacent area. In the process of cold rolling, due to the thin thickness, the transverse flow of the metal can not eliminate the local high point. Although in terms of size, the thickness of the local high point position is only a few microns different from the thickness of other positions, when the wear-resistant plate is rolled up, hundreds of layers of local high point accumulation will eventually form a reinforcement phenomenon on the surface of the wear-resistant plate, resulting in unilateral reinforcement, intermediate reinforcement, bilateral reinforcement, etc., among which the wear-resistant plate is most likely to produce unilateral reinforcement, seriously affecting the surface quality of the product.
The main reason for the local high point of the wear-resistant plate is the uneven wear of the work roll and the uneven cooling of the rolling line. Specifically refers to:
1, uneven roll wear
As the rolling process increases, the roll will wear, especially the contact position of the wear-resistant plate edge, because the wear-resistant plate edge temperature is low, high hardness, wear is particularly serious.
In order to avoid serious local wear on the roll edge, under the premise of controlling the planned rolling quantity per unit, the roll shifting strategy is optimized, and the roll shifting mode is optimized from the fixed step size originally designed to variable step size. The roll step length of each roll cycle changes. Through optimization, the local serious wear caused by long-term contact between the same part of the roll and the edge of the wear-resistant plate can be avoided, and the probability of local high and low can be reduced.
2, uneven cooling
During the hot rolling process, if the local cooling of the wear plate is uneven due to problems such as leakage of the frame, the hardness is high, and this part of the high hardness area is difficult to deform during the cold rolling process, and the thickness after rolling is slightly higher than the area with lower hardness, in fact, it also forms a local high point.
Aiming at the cooling problem, the cooling nozzles of rolling line are replaced and maintained regularly to ensure the uniformity of rolling temperature. At the same time, strengthen the maintenance of the equipment, reduce the water leakage of the rolling line, and avoid the local hardness of the wear plate caused by water leakage.
