JPS5819749B2 - Pickling control method - Google Patents

Description

Detailed Description of the Invention This invention detects the amount of scale in the strip width direction during pickling of steel slabs, etc., and uses the detection signal to determine the electrolytic current or pickling liquid jet amount in the width direction. This invention relates to a pickling control method that selectively increases the reaction rate in areas with a large amount of scale through adjustment.

The purpose of the pickling line for steel strips, etc. is to remove scale, and if the line speed is increased to shorten the processing time to improve work efficiency, scale will be removed from both widthwise end faces of the sl-IJ tube. It often happens that parts that are not shown appear.

On the other hand, conventional automatic control methods for pickling lines merely keep some of the reaction conditions, such as the temperature and concentration of the pickling solution, constant.

For this reason, line speeds related to work efficiency have traditionally relied solely on the experience of workers, and have been determined with sufficient margin to ensure complete scale removal. .

However, the scale thickness of a steel strip is generally thinner at the center and thicker at both ends in the width direction.

In addition, since the reaction conditions in the pickling tank are uniform throughout the tank, the reaction time of the pickling process is faster at the center where the scale is thinner and slower at both widthwise ends where the scale is thicker.

Therefore, if the reaction is promoted until descaling is completed at both ends in the width direction, there is a problem that the central part becomes over-pickled.

This invention was devised to solve the above problem, and the scale amount distribution in the width direction of the strip passing through the pickling tank is detected by a scale detector that detects the strip in the width direction. A detection signal is sent via an amplifier and a controller to an electrode for flowing an electrolytic current or a pickling liquid jet device provided in the pickling liquid behind the scale detector, and either of these is used to generate a signal in the width direction of the scale detector. This invention provides a pickling control method characterized by controlling the electrolytic current amount or the pickling liquid jet amount in accordance with the classification.

Therefore, as a means to change the reaction conditions according to the above-mentioned widthwise divisions, a method is adopted in which the amount of electrolytic current is adjusted and flowed, or a method in which the jet amount of the pickling solution is adjusted and jetted. Another possible method is to use ultrasound.

Further, as the scale amount detecting means of the scale detector, a method using a change in the amount of reflected light is adopted, but other detection methods may be used.

In addition, the location of each device is such that the scale detector is placed closer to the outlet side than the center of the pickling tank, and the electrode or pickling liquid jet device is placed behind it, that is, closer to the outlet side, for flowing electrolytic current. It is preferable to place

In addition, in this case, it is necessary to determine the maximum reaction value that can be removed by the electrolytic current or pickling liquid jet in advance by experiment, and it is important to adjust the line speed so that the maximum reaction value is always obtained. .

In addition to the above-mentioned devices, a scale detector similar to the above-mentioned scale detector can be placed at the outlet side of the pickling tank to check the presence or absence of scale on the strip after pickling, thereby making it possible to further adjust the line speed. The effects of this invention are made even more complete.

Next, the description of the present invention will be supplemented based on the embodiments shown in the figures.

In FIG. 1, 1 is a pickling tank, and 2 is a steel strip to be pickled thereby.

3 is a coil unwinding machine, and 4 is a coil winding machine, in which the steel strip 2 is passed through the pickling tank 1 in the direction shown by the arrow in the figure, and the pickling liquid filled therein is passed through the pickling tank 1 in the direction shown by the arrow in the figure. The pickling treatment is carried out by.

Reference numeral 5 denotes a scale detector which is important in this invention, and is installed in the middle of the path of the steel strip IJ tube 2 in the pickling tank 1 so as to be able to detect the scale amount of the steel strip 2 passing through it by dividing it in the width direction. It is located in

6 is also an electrode for applying electrolytic current, which is important in this invention, and is arranged in the pickling solution behind the scale detector 5, and is arranged in the widthwise direction corresponding to the widthwise division of the scale detector 5. Electrode 6 is shown in the figure to enable energization division.
Although an example is shown in which a pickling liquid jet device 6' is disposed at this position, a pickling liquid jet device 6' may be disposed at this position instead.

Reference numeral 7 denotes an amplifier, which outputs a scale amount distribution signal 8 of each amount in the width direction of the steel strip 2 detected by the scale detector 5.
Then, the signal is sent to the next electrolytic current controller (or pickling liquid jet controller) 9, which adjusts the next electrolytic current source (or pickling liquid jet flow rate) according to a preset adjustment program. Adjustment device) 10 converts it into setting signals 11 divided in the width direction, and controls the electrode 6 or the pickling liquid jet device 6'.
The electrolytic current amount (or pickling liquid jet amount) is adjusted according to the setting signal 11.

12 is a scale detector further disposed on the outlet side of the pickling tank, and 13 is an abnormal scale controller to which a signal detected by the scale detector is sent.

14 is a line speed controller, and this line speed controller 14 receives a line speed target value signal sent from the electrolysis current controller (or pickling liquid jet flow rate controller) 9 as shown by the arrow in the figure. The winding speed of the coil winder is adjusted to keep it at a speed suitable for removing scale from the steel strip 2, and the scale detector 12 located on the outlet side of the pickling tank detects the winding speed after the pickling process. When an abnormal scale is detected on the steel strip 2, the abnormal scale controller 13 to which the signal was sent sends a setting signal converted according to the adjustment program set in advance to the line speed controller 14, where the signal is sent to the line speed controller 14. Furthermore, it is converted into a line speed to adjust the winding speed of the coil winder 4.

In addition, FIG. 2 is a side sectional view of the main parts of the apparatus when implementing the method of the present invention in a newly constructed line, and FIG. 3 is a plan view thereof, 15 is a pinch roll, 16 is a recovered acid Or it shows the new hydrochloric acid supply pipe.

FIG. 4 is an explanatory diagram showing the configuration of the pickling liquid jet flow regulating valve.

The pickling control method of the present invention detects the distribution of scale amount in the width direction of the strip, and adjusts the pickling reaction rate in the width direction of the strip according to the detection signal, so that the pickling reaction rate in the strip width direction is reduced. Since the speed is selectively increased, scale removal in the width direction of the strip is performed uniformly, and work efficiency can be rationally adjusted according to the amount of scale, resulting in improved work efficiency. It brings about effects such as being able to

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention. FIG. 2 is a side sectional view showing the main parts of the apparatus when the present invention is implemented in a newly established line, and FIG. 3 is a plan view thereof. FIG. 4 is an explanatory diagram of the pickling liquid jet flow regulating valve. 1... Pickling tank, 2... Steel strip,
3... Coil payout machine, 4... Coil winding machine, 5... Scale detector, 6...
Electrolytic current electrode, 6'... Pickling liquid jet flow regulating valve, 7
......Amplifier, 8...Scale signal, 9
......Electrolysis current controller (or pickling liquid jet flow rate controller), 10...... Electrolysis current power supply (or pickling liquid jet flow rate adjustment device), 11... Setting Signal, 12...
... Scale detector, 13 ... Abnormal scale controller, 14 ... Line speed controller, 15 ...
...Pinch roll, 16...Recovered acid or new hydrochloric acid supply pipe.

Claims (1)

[Claims] 1) A scale detector is placed in the middle of the IJ tube path in the pickling tank that can detect the amount of scale on the IJ tube passing through it by dividing it in the width direction. An electrolytic current electrode or a pickling liquid jet device divided in the width direction corresponding to the detection section of the scale detector is disposed in the solution, and the detection signal from the scale detector is transmitted to the electrolytic current electrode through an amplifier and a controller. A pickling control method characterized by sending electrolytic current to a current electrode or a pickling liquid jet device and adjusting the electrolytic current amount or the pickling liquid jet amount.