The accurate control of plating thickness is one of the most basic directions in galvanizing production, but this problem is particularly important in the galvanizing of heavy plate. This is because:
(1) the thickness of zinc coating of thick plate has reached the upper limit of air knife control, so it is difficult to control accurately.
(2) If the thickness of zinc coating on thick plate is large, if the error is large, the customer is not satisfied if the thickness is lower than the standard thickness, and the impact of exceeding the standard thickness on the production cost is relatively large.
(3) The length of a coil of hot-rolled plate is very short. Although an on-line galvanizing gauge is installed, there is a distance of more than 100 meters from the air knife to the thickness gauge through the cooling tower after plating. Taking 3.0 mm steel coil as an example, its total length is only about 400 meters, and the delay of galvanizing accounts for 25%. With the adjustment time, one coil is soon finished.
(4) The thickness difference and shape of hot-rolled plate have great influence on the amount of zinc plating, which is not conducive to the control of uniformity and accuracy of plate coating. The main factors affecting the thickness of coating are: production line speed, air knife spacing and gas pressure of air knife. We can collect the data of different ranges of the above projects and the results of zinc plating amount in production, summarize the relationship between the zinc plating amount and various variables, and obtain the mathematical model formula to guide the production operation, so that the data of various projects can be set in advance To the result close to the standard value, and then fine-tuning, so that the amount of zinc plating can be accurately controlled, improve product quality and reduce production costs. Through this relationship, on the premise of knowing the required galvanizing quantity standard, the process parameters to be guaranteed, such as production line speed and air knife spacing, can be determined first according to the actual production situation, then the required air pressure can be calculated back and set in advance, and then the initiative of zinc plating quantity control can be mastered by adjusting according to the results.