Stop spot control method for shallow slot turbulent pickling line

Abstract

A stop spot control method for a shallow slot turbulent pickling line comprises the following steps: 1) strip steel sequentially enters an acid bath for pickling and then enters a bleaching bath, so the residual chloridion on the surface can be rinsed; 2) corrosion inhibition solution is prepared in a corrosion inhibition solution tank in advance, pure water and corrosion inhibitor are sequentially added to the corrosion inhibition solution tank, and the addition volume of the corrosion inhibitor is 0.1wt%-2.0wt% of the addition volume of the pure water; 3) when the pickling line stops, a bleaching water pump stops operating, and the bleaching water is drained completely; 4) the corrosion inhibition solution in the corrosion inhibition solution tank is injected to the bleaching bath by a solution feed pump until the strip steel is completely immersed; 5) the pickling line is restarted, a corrosion inhibition solution emptying valve is opened, the corrosion inhibition solution is emptied to the corrosion inhibition solution tank, and then the corrosion inhibition solution emptying valve is closed; and a bleaching water reflow valve is opened, the bleaching water pump starts to operate and clean the strip steel by spraying again. the stop spot control method can effectively prevent the stop spot from being formed on the surface of the strip steel, the pickling efficiency is greatly improved, and the pickling line plate yield and rate of quality products are also improved.

Description

technical field [0001] The invention relates to strip steel pickling technology, in particular to a method for controlling parking spots of a shallow groove turbulent flow pickling unit. Background technique [0002] Hot-rolled strip steel is rolled and coiled at high temperature, and the oxide scale formed on the surface of the strip steel under this condition firmly covers the surface of the strip steel and covers the defects on the surface of the strip steel. Therefore, before the strip steel is cold-rolled, its surface oxide scale must be removed to remove defective strip steel. [0003] At present, the commonly used method for removing iron scale in cold rolling production line is hydrochloric acid pickling. The emergence of the combined washing and rolling mill has greatly improved the efficiency of cold rolling and doubled the production capacity. However, as the production line is extended, the continuous unit often encounters accident shutdown or maintenance shutd...

AI Technical Summary

Problems solved by technology

It not only seriously affects the surface quality of the pickling strip, but also produces a series of consequences such as difficulty in subsequent rolling and decreased adhesion of the coating. The finished product rate is reduced and the scrap rate is increased, which seriously affects product quality and economic benefits

[0004] Parking spot defect is the number one defect of cold-rolled pickling unit. From the current point of view, there is no good control method. For short-term parking spot defects, the rewinding method is generally used, that is, the strip is returned to the acid tank for pickling again , can reduce the degree of parking spot defects to a certain extent, but cannot completely eradicate

[0005] Chinese patent CN200620127640.X discloses a continuous pickling unit capable of spot-free pickling of strip steel, which is used to solve the problem of eliminating parking spots in strip rolling

[0006] However, in the actual production process, the rewinding method mainly has the following problems: 1) The acid liquid is taken out of the acid tank during the rewinding process, corroding the equipment outside the acid tank, which has a large side effect on the equipment; 2) The strip steel is poured out Repeated pickling after the acid tank is equivalent to adding an additional pickling process, which has a great impact on the production capacity of the unit; 3) Repeated pickling on the parking spots after rewinding will make the strip thin locally, and thickness fluctuations during rolling will cause thick Poor, in severe cases, it may even cause broken belts; 4) For serious parking spots, remove them and judge them as waste, resulting in loss of quality and yield

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