JPH0356699A - Method and device for descaling strip - Google Patents

Abstract

PURPOSE:To efficiently descale the surface of a band steel by using the steel as an anode, injecting an electrolyte from a cathode plate provided above and below the steel to renew the electrolyte on the steel surface, stably passing the steel through the center between the cathodes and applying a current. CONSTITUTION:The band steel 4 having scales on its surface is passed through a neutral electrolyte 2 of Na2SO4, etc., in an electrolytic cell 1 by conductor rolls 3 and 3'. The steel 4 is used as an anode through a DC power source 7 and traveled between the cathodes 5 and 5' set in the electrolyte 2, and a current is applied. Many electrolyte injection ports are provided on the surface of the cathodes 5 and 5' facing the steel 4, the electrolyte is circulated by a pump 11 and injected from the injection ports of the cathodes 5 and 5', and the steel 4 is smoothly traveled by the liq. pressure without itself being brought into contact with the cathodes 5 and 5'. Since the fresh electrolyte is constantly supplied to the surface of the steel 4, the scales on the surface of the steel 4 are uniformly removed at a high rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for electrolytic descaling of a strip, and in particular to a method and apparatus for electrolytic descaling of a stainless steel plate by neutral salt electrolysis. [Prior Art] The so-called electrolytic descaling method, in which descaling is performed by passing a strip through an electrolytic solution, is well known. However, the conventional electrolytic descaling method and apparatus, as shown in FIGS. 4 and 5, have sink rolls 20 and 20' on the inlet and outlet sides of the electrolyte layer 1 filled with the electrolytic solution 2, respectively.
A plurality of pairs of support rolls 21 are provided between the rolls 20 and 20', and the support rolls 21
Negative i-electrode pair 22, 22' and anode electrode pair 2 are alternately sandwiched between
3.23' are arranged, and in the process of passing the strip 4 into the electrode solution 2 while being supported by the support rolls 20, 20', the cathode electrode 22. The strip surface is descaled by the electrolytic current flowing through 22'. [Problem to be solved by the invention] The conventional electrolytic descaling method and device
The electrolytic current flows from the anode electrodes 23.23' alternately arranged across the support roll 21 to the cathode electrodes 22.22' via the strip 4 through the strips 4 supported by the support rolls 21. Because it descales, sabotroll 21
The anode T electrode 23.23' and the cathode electrode 22.22' are indispensable, and it is necessary to keep a large distance between the sink rolls 20.20' on the inlet and outlet sides where they are arranged, and to create a large electrolytic layer. 1 and a large amount of electrolyte 2 are also required, which inevitably increases the size of the device itself. Further, the strip 4 in the electrolytic layer 1 is connected to a support roll 21.
However, the space between the support rolls 2l is free, and if the strip 4 that is being passed between these rolls becomes wavy, the gap between the electrodes 22, 22' and 23, 23' and the strip 4 will change. However, the electrolytic current must be increased to ensure a sufficient electrolytic current even at the maximum gap, resulting in increased running costs.

Means for Solving the Problem] According to the present invention, in an electrolytic descaling method in which descaling is performed while a strip is continuously passed through an electrolytic solution, an anode is provided on the inlet and outlet sides of the electrolytic layer. providing a conductor roll, and providing at least a pair of cathode electrodes facing each other across the strip passing path between the rolls;
Further, each of the cathode electrodes is provided with a fluid ejection hole, and the strip is heated by the fluid pressure ejected from the fluid ejection hole.
A method for disgaling a strip, which is characterized in that the strip is passed from the inlet conductor roll side to the outlet conductor roll side while being held approximately in the center between the electrodes, and the strip is continuously passed through an electrolytic solution. In an electrolytic dayscaling device that performs descaling while stripping, conductor rolls connected to an anode power source are provided on the inlet and outlet sides of the electrolytic layer, and a strip passing path is provided between the rolls so that the strip is immersed in the electrolyte. Descaling of a strip characterized by providing cathode electrodes connected to at least a pair of cathode power supplies facing each other, and the cathode electrodes being provided with fluid ejection holes opening toward the strip passage path. The device is obtained. [Operation of the Invention] According to the present invention, a conductor roll 3.3' connected to an anode power source is used instead of the conventional sink roll 20.20', and the roll 3.3' is used as an anode electrode, and a strip is removed from the electrode. cathode electrode 5.5 disposed in electrolyte 2 via 4
Electrolytic current is applied directly toward ′. In addition, the strip 4 is stably held approximately in the center between the cathode electrodes 5.5' by the fluid pressure from the fluid jet holes 9.9' provided in the cathode electrodes 5, 5'. ′
There is no contact trouble caused by the waving of the strip 4 during threading between the strips. [Example] The following is an explanation based on the example shown in FIGS. 1 to 3. In FIG. 1, reference numeral 1 denotes an electrolytic layer, and conductor rolls 3 and 3' partially immersed in an electrolytic solution 2 such as a neutral salt electrolytic solution are disposed on the inlet and outlet sides of the electrolytic layer, respectively. ing. Between the conductor rolls 3.3', two pairs of cathode electrodes 4.4' are arranged symmetrically across the moving path of the strip 4 connecting the conductor rolls 3.3' so as to be immersed in the electrolyte 2. is provided. Denoted at 5.5' are deflector rolls provided on the inlet and outlet sides of the electrolyte layer 1, respectively, which guide the strip 4 into the electrolyte layer 1 via the inlet deflector roll 5, and guide the strip 4 into the electrolyte layer 1 through the outlet deflector roll 6'. It is designed to be sent from the electrolytic layer 1 through the electrolytic layer 1. Referring also to FIG. 2, the conductor roll 3
．． 3' and cathode electrodes 5 and 5' connect the conductor rolls 3 and 3' to the anode side of the power supply 7, and the cathode electrodes 5 and 5' to the cathode side. Referring also to FIG. 3, jackets 8 and 8' are provided on the opposite side of the strip 4 passage of the cathode electrodes 5 and 5', and fluid jet holes are provided on the side of the strip 4 passage. 9.9' is open. The fluid ejection holes 9,9' are arranged approximately perpendicularly to the strip 4, and one or more holes are arranged along the center of the threading path of the strip 4 or in a staggered manner with the center of the threading path of the strip 4 sandwiched therebetween. However, the fluid ejection holes 9, 9' are preferably a pair of holes 9, 9' that intersect with each other in the width direction of the strip in the respective cathode electrodes 5, 5', and are opposed to each other. A portion of the fluid ejected from the hole is removed from the strip 4.
A confined fluid cushion portion 10, 10' is formed between the cathode electrodes 5 and 5'. 11.11' is a pump, which is installed in the pipe 1313' that connects the sub-tank 12 and the jacket 8.8'. Note that this pump 11.11' may be a variable displacement pump to control the cushion pressure of the fluid cushion portion 10.10' or a fixed displacement pump, as shown in the diagram in the piping 13.13'. It is desirable to install a flow control valve that does not.

Next, the day scaling effect of the present invention will be explained. When a current is passed through the electrolytic layer 1 while passing the strip 4, the current flows from the conductor rolls 3, 3', through the strip 4, through the electrolytic solution 2, and to the cathode electrode 5.5'. Therefore, the scale attached to the surface of the strip 4 is removed by an electrolytic reaction using the strip 4 as an anode. At this time, when descaling a stainless steel plate in an electrolytic solution of a neutral salt such as sodium sulfate (Na2 SO4), the electrolytic reaction is + Cr2 (h +5H20 - 2Cr04 +10H
+6e・111Cr20g + 4}120 4 C
The oxygen evolution reaction r20-7- + 88++6e-(2) occurs, and on the cathode side, 2hO + 2e-
H2 + 20HT: −++・・−+・・・−+・−
A hydrogen generating reaction called f4) occurs secondarily. If +12 and 02 generated during this electrolytic reaction fill between the strip 4 and the cathode electrode 5.5', the cutoff resistance voltage will increase. A hole 9.9' is provided to connect the strip 4 and the cathode electrode 5.5'.
Since the electrolyte 2 is forcibly circulated between the H2
and 02 can be discharged quickly. Therefore, the concentration of the electrolytic solution 2 between the strip 4 and the cathode electrodes 5, 5' can be kept substantially constant at all times, so that a stable electrolytic reaction can be carried out. Moreover, in the present invention, since current is applied directly to the strip 4 from the conductor roll 3, 3', the conventional anode→electrolytic layer→
Compared to the strip energization method, there is no voltage drop caused by the electrolyte 2 on the anode side, and a fluid cushion between the strip 4 and the cathode electrodes 5, 5' prevents the steel plate from waving, so that Since they are kept at approximately constant intervals, the density of the electrolytic current can also be kept uniform. [Effects of the Invention] According to the present invention, the conventional anode electrode and sabotroll can be omitted, so the device can be made smaller, and the distance between the strip and the cathode electrode can be kept constant at all times. The electrolyte in this area is forcibly circulated so that the H2 or 02 generated in the strip does not accumulate between the strip and the cathode electrode. Since non-uniformity of electrolytic current can be prevented, electrolytic descaling efficiency can be improved, and power consumption can also be reduced.
This has the effect of keeping running costs low.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the present invention. Figure 2 is the same wiring system diagram, Figure 3
The figure is a sectional view taken along line 1 in Figure 1, Figure 4 is a schematic diagram showing an example of a conventional electrolytic descaling device, and Figure 5 is a wiring diagram of the same. 1... Electrolyte layer 2... Electrolyte solution 3.3
′・・・Conductor roll

Claims (1)

[Claims] 1) In an electrolytic descaling method in which descaling is carried out while a strip is continuously passed through an electrolytic solution, conductor rolls serving as anodes are provided on the inlet and outlet sides of the electrolytic layer, and At least a pair of cathode electrodes are provided between the rolls, facing each other across the strip passing path, and each of the cathode electrodes is provided with a fluid ejection hole, and the strip is heated by the fluid pressure ejected from the fluid ejection hole. A method for descaling a strip, characterized in that the strip is passed from the inlet conductor roll side to the outlet conductor roll side while holding the strip approximately in the center between the cathode electrodes. 2) In an electrolytic descaling device that performs descaling while continuously passing a strip through an electrolytic solution, conductor rolls connected to an anode power supply are provided on the inlet and outlet sides of the electrolytic layer, and an electrolytic At least a pair of cathode electrodes connected to a cathode power supply are provided, which are immersed in the liquid and facing each other across the strip passing path, and each cathode electrode has a fluid ejection hole opened toward the strip passing path. A strip descaling device characterized in that it is provided with.