JPH09302488A - Cleaning control method in cleaning equipment of cold rolled steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of efficient cleaning and removing attached residual steel powders in oil removing and cleaning equipment to remove the oil adhered to a steel plate after the cold rolling and before the annealing. SOLUTION: In cleaning equipment to remove the oil stuck to a cold rolled steel plate after the cold rolling and before the continuous annealing or batch annealing, the radiation factor, the color or tone of a steel plate 1 is detected after the cleaning as an index to indicate the cleaning degree, the detected value is compared with the predetermined radiation factor, the color or tone of the steel plate by inserting the detected value in the relationship to the steel powder amount on the steel plate after cleaning, and adjustment is made by using either of or a plurality of a steam adding means and a detergent adding means in the cleaning equipment, and a steam adding means, an electrolytic current adding means, and a detergent adding means in an electrolytic cleaning equipment so as to realize the radiation factor, or the color or tone to obtain the prescribed residual steel powder. No residual steel powders are left on the steel plate after cleaning, and an excellent product can be constantly obtained when treated in the succeeding process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning control method in a cleaning device for removing oil from a cold rolled steel sheet after cold rolling and before annealing.

[0002]

2. Description of the Related Art Conventionally, in the annealing of thin sheets, regardless of continuous annealing or batch annealing, before the annealing after cold rolling, the cold rolling oil adhering to the steel sheets is removed by a continuous washing apparatus for steel sheets.
An example of a typical cleaning device will be described in detail with reference to FIG.

In FIG. 4, a steel plate 1 is first cleaned in a scrubber zone 2 with a cleaning liquid, for example, 0.5 to 0.5 of sodium orthosilicate.
The 1% solution is heated to 50 ° C. to 80 ° C., and while being applied to the steel plate 1, the oil is physically removed by the brush roll 3. Next, in the electrolysis device 4, a hot water temperature of 60 to 90 ° C. with 1 to 2% of sodium orthosilicate.
Solution is contained in the steel sheet 1, and the steel sheet 1 is negatively or positively electrolyzed (3 to 5 A / dm ² ) by the electrode 5 to generate hydrogen or oxygen from the surface of the steel sheet 1. Removed oil to float.

Further, a 0.5 to 1% solution of sodium orthosilicate is heated to 50 to 80 ° C. in the scrubber zone 6, and the oil is physically removed by the brush roll 7 while it is applied to the steel plate 1. Next, in the hot rinse zone 8, in order to remove the sodium orthosilicate adhering to the steel plate, 50 ° C to 80 ° C.
The washing water heated to 1 is applied to the steel plate 1.

As a measure for enhancing the cleaning ability, a method of spraying an alkaline solution to be introduced into an electrolytic cell as disclosed in JP-A-57-18400 and JP-A-54-8.
As seen in Japanese Patent No. 0241, a method of applying alternating alternating electrolysis in an electrolytic cell has been proposed, but it has not been put to practical use.

[0006]

[Problems to be Solved by the Invention] Normally, standard conditions such as the concentration of sodium orthosilicate, hot water temperature, line speed, etc. are determined with a margin (considering safety allowance) based on the result of the product. However, the amount of cold-rolled oil is changed while watching the elongation of the steel sheet, and the cold-rolling speed of the steel sheet is also changed before and after welding the steel sheet and while watching the cold-rolled shape. Are different in the same coil, and also in cold rolling chance.

For this reason, sometimes the oil adhering to the steel sheet is not completely removed by the cleaning device, and in the case of the surface-treated steel sheet in the post-process, appearance defects such as plating failure occur, and in the case of grain-oriented electrical steel sheet. In some cases, the oxygen addition amount (mainly SiO ₂ amount) during decarburization annealing was different, and a film defect might occur.

In view of such conventional problems, the present invention adjusts the condition of the cleaning apparatus by measuring the state of oil adhered to the steel sheet after cleaning, so that the oil adhered to the steel sheet can be removed regardless of the cold rolling condition. The objective is to stably obtain a steel sheet without product defects in the subsequent process by always completely removing it.

[0009]

Means for Solving the Problems The gist of the present invention is, in a cleaning apparatus for removing oil of a cold rolled steel sheet after cold rolling and before performing continuous annealing or batch annealing, a steel sheet as an index showing the degree of cleaning after washing. The emissivity or color / tone of the steel sheet is detected, and that value is inserted into the predetermined value of the relationship between the emissivity or color / tone of the steel sheet and the amount of residual iron powder after washing, and the values are compared to determine the prescribed residual iron powder. One of the means of adding steam / cleaning agent in the cleaning apparatus and adding steam / electrolytic current / cleaning agent in the electrolytic cleaning apparatus so that the emissivity or color / tone is obtained to obtain the quantity. A cleaning control method in a cold-rolled steel sheet cleaning apparatus is characterized by adjusting one or a plurality of means in combination.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In order to quantify the degree of fouling of cold-rolled steel sheet due to oil adhesion, etc., in an electrolytic cleaning device containing 80% hot water containing 2% sodium orthosilicate, the current density was set to 5 A / dm ² .
When the residence time of the steel sheet was changed and the relationship with the emissivity of the steel sheet was examined, an extremely strong correlation as shown in FIG. 3 was obtained.

Usually, during cold rolling, it is known that the iron powder separated from the steel sheet adheres to the steel sheet together with the rolling oil, and the iron powder is simultaneously removed together with the oil removal in the cleaning device. It is considered that the emissivity of the steel sheet changed according to the removal of powder.

In order to prove this hypothesis, the amount of iron powder remaining on the steel sheet under various cleaning conditions was chemically analyzed, and the correlation between the iron powder amount and the emissivity of the steel sheet was obtained. Thus, a very strong correlation was found. Also, when the relationship between the amount of residual iron powder on the steel plate and the color / tone of the steel plate was obtained,
Similarly strong correlation was obtained.

As described above, the degree of cleaning of the steel sheet is related to the amount of iron powder adhered to the steel sheet, and the fact that this is strongly related to the emissivity, color and color tone of the steel sheet has made the present invention. .

The present invention will be described in detail with reference to FIG. 1 based on the following embodiments. In the scrubber zone 2, while the water having a concentration of 0.8% sodium orthosilicate is heated to 60 ° C. and applied to the steel plate, oil is removed by the brush roll 3. Next, in the electrolytic cell 4, 1.5% sodium orthosilicate and hot water at a temperature of 75 ° C. are contained, and the electrode 5 is used to apply negative electrolysis (current value 4 A / dm ² ) to the steel sheet 1 to generate hydrogen. Alternatively, oxygen is generated and oil is removed by air bubbles to float.

Further, while a 0.7% solution of sodium silicate heated at 65 ° C. in the scrubber zone 6 is applied to the steel plate, the oil is physically removed by the brush roll 7. Next, in the hot rinse zone 8, only hot water at 60 ° C. is applied to the steel plate to completely remove the sodium orthosilicate adhering to the steel plate.

At the exit side of the hot rinse zone 8, the steel plate 1
There is a sensor 9 capable of measuring the emissivity or the color / tone of the signal, and the signal measured by the sensor 9 enters the controller 10. The relationship between the emissivity or color / tone of the steel sheet and the amount of oil containing iron powder is input to the controller 10 in advance.
When the set emissivity or color / tone is not reached, a signal is sent to the controller 11 to open the solenoid valve 12 for steam and raise the hot water temperature in the scrubber zone 2.

When the set value is not reached even by this operation,
A signal is sent to the controller 13, and the current flowing through the electrode 5 is adjusted by the controller 15 to increase the amount of hydrogen / oxygen generated from the surface of the steel plate to enhance the effect of removing adhered oil and floating, or by using the steam solenoid valve 14. Open and raise the temperature of the electrolytic bath 4.

When the set value is not reached even by this operation, a signal is sent to the controller 16, the steam solenoid valve 17 is opened, and the hot water temperature in the scrubber zone 6 is raised. By the above operation, oil containing iron powder adhered to the steel sheet can be completely removed regardless of the difference in cold rolling conditions.

In the present embodiment, an example is shown in which the hot water temperature is adjusted by detecting the emissivity of the steel sheet after cleaning, but as shown in the following example, the concentration of the cleaning agent may be adjusted independently or the hot water temperature may be adjusted. You may also adjust it. An example of adjusting the concentration of the cleaning agent based on the embodiment of FIG. 1 will be described in detail below. The steam supply solenoid valves 12, 14, 17 used in the first embodiment are the same as the cleaning agent supply solenoid valves 12, 1 in the second embodiment.
In other words, 4,17.

The relationship between the emissivity or color / color tone of the steel plate and the amount of oil containing iron powder is attached to the controller 10 in advance, and is adjusted when the set emissivity or color / color tone is not reached. Solenoid valve 12 for supplying cleaning agent by sending a signal to total 11
Open wide to increase the concentration of the cleaning agent in the scrubber zone 2.

When the set value is not reached even by this operation, a signal is sent to the controller 13 and the current flowing through the electrode 5 is adjusted by the controller 12 to increase the amount of hydrogen / oxygen generated from the surface of the steel sheet, and The removal floatation effect is enhanced or the cleaning agent replenishing solenoid valve 14 is opened wide to increase the cleaning agent concentration in the electrolytic bath 4.

When the set value is not reached even by this operation,
A signal is sent to the controller 16, the cleaning agent replenishing solenoid valve 17 is opened, and the cleaning agent concentration in the scrubber zone 6 is increased. By the above operation, oil containing iron powder adhered to the steel sheet can be completely removed regardless of the difference in cold rolling conditions.

The effect of the present invention can be obtained with either one of the steam supply system and the cleaning agent supply system. However, if both facilities are installed side by side and combined and controlled, it is possible to quickly respond to the cleaning situation. it can. By these adjustments / controls, there was no defective plating or defective appearance of the coating on the electrical steel sheet.

As described above, according to the present invention, by adopting various cleaning degree adjusting means in the order of the scrubber zone 2 → electrolysis tank 4 → scrubber zone 6 in accordance with the cleaning process of the steel sheet, the cleaning speed can be increased according to the cleaning condition. Moreover, the target value for removing the oil adhered to the steel plate can be accurately achieved.

[0025]

[Example] The plating shown in Table 1 and cold-rolled steel sheets under various treatment conditions for electromagnetic steel sheets were washed under the conditions shown in the same table, and the amount of residual iron powder after washing was chemically determined. Do the processing
The relationship with the product defect rate is shown in the table. In the "Control change amount" column of the table, the portion indicated by an arrow indicates the control change amount in each process. As is clear from Table 1, in Material Nos. 4 to 8 and 12 to 17 of the present invention, Comparative Examples 1 to 3 and 9 to 11 are shown.
The amount of residual iron powder after washing was extremely small compared to the above, and good products could always be obtained when processed in the subsequent process.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

According to the present invention, the residual iron powder after washing the cold-rolled steel sheet is extremely small, the plating in the subsequent steps and the coating film of the electromagnetic steel sheet are excellent, and a good product can always be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing processing steps in a cold-rolled steel sheet cleaning apparatus of the present invention.

FIG. 2 is a chart showing a relationship between a residence time of a steel sheet and an emissivity in an electrolytic cleaning device.

FIG. 3 is a chart showing the relationship between the amount of residual iron powder on a steel plate and the emissivity in an electrolytic cleaning apparatus.

FIG. 4 is a diagram showing processing steps in a conventional cold-rolled steel sheet cleaning apparatus.

[Explanation of symbols]

1: Steel plate 2,6: Scrubber zone 3,7: Brush roll 4: Electrolyzer 5: Electrode 8: Hot rinse zone 9: Sensor 10, 11, 13, 15, 16: Controller 12, 14, 17: Steam supply Solenoid valve for cleaning, or solenoid valve for supplying cleaning agent

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeharu Kataoka 1-1 Hibahata-cho, Tobata-ku, Kitakyushu City Shin Nippon Steel Yawata Works Co., Ltd.

Claims (1)

[Claims] 1. A cleaning device for removing oil from cold-rolled steel sheet after cold rolling and before continuous annealing or batch annealing, wherein emissivity or color / tone of the steel sheet is detected as an index indicating the degree of cleaning after washing. , The value is inserted into the relational value between the emissivity or color / tone of a predetermined steel plate and the residual iron powder amount of the steel plate after cleaning and compared, and the emissivity or color for obtaining the predetermined residual iron powder amount is compared. To add color, add steam and detergent in the cleaning device, and add steam in the electrolytic cleaning device.
A cleaning control method in a cold-rolled steel sheet cleaning apparatus, characterized in that any one or a plurality of means for adding an electrolytic current and a cleaning agent are used together for adjustment.