JPH0841697A - Descaling method and descaling device for coiled stainless steel wire - Google Patents

Abstract

PURPOSE:To suppress a treating agent cost and energy consumption unit to a lower level, to dispense with lower equipment and maintenance costs and to efficiently descale a coiled stainless steel wire. CONSTITUTION:The coiled stainless steel wire 4 wound to a coil form is hung by means of a hanger 5 and is immersed in this state into a neutral salt bath 2. The anode side of a DC power source 8 is connected to the hanger 5 to set the stainless steel wire side as anode. The outer peripheral side of the coil of the stainless steel wire 4 and the inner peripheral side of the coil are respectively provided with a recessed shape electrode 6 and round shape electrode 7 which are connected to the cathode side of the DC power source 8. The stainless steel wire 4 is subjected to a neutral salt electrolytic treatment at a current density maintained at about 3 to 10A/dm<2> between the stainless steel wire 4 and the electrodes 6, 7, by which the scale formed on the surfaces of the stainless steel wire 4 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention efficiently removes a scale formed on the surface of a coiled stainless steel wire wound in a coil state at low cost and also under a good working environment. The present invention relates to a descaling method and a descaling device for a coiled stainless steel wire rod used in.

[0002]

2. Description of the Related Art In rolled stainless steel wire rods and annealed stainless steel wire rods, chromium oxide (trivalent chromium Cr ₂ O ₃ ) is formed as oxide scale on the surface thereof.

Therefore, it is necessary to remove such scales, but in the conventional case, a caustic soda (NaOH) or sodium nitrate (NaNO ₃ ) which is strongly alkaline is used to keep it at a high temperature of 400 ° C. or more for a required time. After performing the salt treatment, the scale was removed by causing a steam explosion by water cooling and peeling the scale.

[0004]

However, in the conventional method for descaling a coiled stainless steel wire rod by salt treatment, caustic soda (N
(aOH) and sodium nitrate (NaNO ₃ ) are used for descaling by causing a chemical reaction to occur, which requires a long time, so the processing capacity is small and melting Since the cost of salt is high and it is necessary to keep it at a high temperature of 400 ° C or higher, the energy consumption rate and equipment maintenance costs are also high, and the use of strong alkaline molten salt for salt treatment also causes pollution. Therefore, it was necessary to handle it carefully.

Therefore, when descaling the coiled stainless steel wire wound in a coiled state, it is not necessary to raise the temperature so much, the cost of the treating agent is low, the treating time is short, and there is a fear of pollution. The challenge was to eliminate the need to do so.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is capable of treating at a relatively low temperature for a short period of time, and it is possible to keep down the cost of treating agent and the energy consumption rate. In addition to being able to do so, the maintenance cost of the equipment can be reduced, there is no fear of pollution, and the purpose is to enable good descaling of the coiled stainless steel wire rod.

[0007]

A method for descaling a coiled stainless steel wire according to the present invention is a coiled stainless steel wire which is wound in a coil state by immersing the coiled stainless steel wire in a neutral salt bath. While making the wire side the anode,
It is characterized in that a cathode is provided in the vicinity of the coil-shaped stainless steel wire rod and a neutral salt electrolysis treatment is performed to alter and remove the scale on the surface of the stainless steel wire rod.

In the embodiment of the method for descaling a coiled stainless steel wire according to the present invention, the stainless steel wire can be connected to the anode through the coiled stainless steel wire suspender. In the aspect, the cathode can be provided in the vicinity of at least one or both of the coil outer peripheral side and the coil inner peripheral side of the coiled stainless steel wire.

Similarly, in the embodiment of the method for descaling a coiled stainless steel wire according to the present invention, the neutral salt bath is set to 70 to 90 ° C. for electrolytic electrolysis of the neutral salt, or the current density is 3 to 10 A. The neutral salt electrolytic treatment may be performed as / dm ² and the neutral salt bath may be 1
The neutral salt electrolytic treatment can be performed using a 0 to 30% aqueous sodium sulfate solution.

Similarly, in the embodiment of the descaling method for a coiled stainless steel wire according to the present invention, the coiled stainless steel wire can be rotated in the circumferential direction during the neutral salt electrolytic treatment. Alternatively, the stainless steel wire after rolling and / or annealing may be soaked in a neutral salt bath, and furthermore,
The coiled stainless steel wire is dipped in a neutral salt bath, and as a previous step, the cathode is electrolyzed using the stainless steel wire side as the cathode, and then the cathode electrolysis with the stainless steel wire side as the anode. You can also

Further, the descaling apparatus for a coiled stainless steel wire according to the present invention suspends a neutral salt bath containing a neutral salt bath and a coiled stainless steel wire wound in a coil state. And the electrode provided near the coil outer circumference side and / or the coil inner circumference side of the stainless steel wire immersed in the neutral salt bath. The present invention is characterized in that a direct current power source for connecting an anode to a stainless steel wire rod and a cathode to an electrode via a tool is provided.

In the embodiment of the descaling apparatus for a coiled stainless steel wire rod according to the present invention, the coiled stainless steel wire rod rotary drive mechanism is attached to the suspender in order to rotate the coiled stainless steel wire rod in its circumferential direction. Also, in the same embodiment, the electrode connected to the cathode is an electrode having a concave cross section or a U shape with an open upper portion arranged on the outer peripheral side of the coil of the stainless steel wire. It is also possible to provide an electrode having a cross-sectional o shape arranged on the inner circumference side of the coil of the stainless steel wire.

The stainless steel applied in the descaling method and descaling apparatus for a coiled stainless steel wire according to the present invention is austenitic stainless steel,
Ferritic stainless steels, martensitic stainless steels, and other stainless steels with a large amount of Cr, and chromium oxide (trivalent chromium Cr ₂ O ₃ ) as a scale on the surface of the wire after rolling or annealing. It has been formed.

Then, the coiled stainless steel wire wound in a coiled state is immersed in a neutral salt bath. As the neutral salt constituting the salt bath in this case, sodium sulfate (Na ₂
SO ₄ ) can be used.

When sodium sulfate is used, it is desirable to use one having a concentration of 10 to 30%. If the concentration of sulfuric acid is too low, the electrolytic treatment will not be carried out sufficiently and quickly, and the concentration of sulfuric acid will be low. If it is too high, local descaling will proceed, so 10-30%
It is desirable to set the concentration within the range.

When the stainless steel wire side is used as the anode, the coiled stainless steel wire wound in a coiled state may be connected to the anode via a suspending tool, or via the suspending tool. Alternatively, the stainless steel wire may be connected to the anode. When the stainless steel wire rod is rotated in the circumferential direction during the neutral salt electrolytic treatment, the coiled stainless steel wire rod rotary drive mechanism such as a rotating roller is provided on the lifting tool to rotate the stainless steel wire rod around its circumference. It can be easily rotated in the same direction, and the power source can be easily connected by connecting to the anode through a rotating roller or the like.

Further, the neutral salt electrolysis treatment can be efficiently performed by providing the cathode in the vicinity of one or both of the coil outer peripheral side and the coil inner peripheral side of the coiled stainless steel wire. Is desirable.

In this case, the electrodes provided on the outer circumferential side of the coil and / or the inner circumferential side of the coil are preferably along the coil shape so that the distance between them is constant. Can have, for example, a concave or U-shaped cross section with an open top, and the electrode provided on the inner circumference side of the coil can have, for example, a O-shaped cross section or a cylindrical shape. The electrodes can be formed by processing a plate material having excellent conductivity and corrosion resistance such as a copper plate.

Furthermore, when sodium sulfate is used, the neutral salt bath is preferably carried out in the range of 70 to 90 ° C., especially around 80 ° C. If the temperature is too low, the neutral salt electrolytic treatment of scale is carried out. May take a long time or become insufficient, and if the temperature is too high, the skin may be roughened due to local descaling.
It is desirable to set it in the range of 70 to 90 ° C.

The current density flowing between the coil-shaped stainless steel wire rod as the anode and the electrode as the cathode is 3 to 10
A / dm ² is desirable, and if the current density is too low, it takes a long time for the neutral salt electrolysis treatment, and if the current density is too high, rough skin due to local descaling progresses. Therefore, the current density is 3 to 10 A / dm
It is desirable to set it to ² .

Further, when the coil-shaped stainless steel wire rod is loaded and unloaded as the electrode provided on the outer peripheral side of the coil, when an electrode having a concave or U-shaped cross section with an open upper portion is used, the open portion of the upper portion is used. In such a case, the coiled stainless steel wire rod may be rotated in the circumferential direction because the neutral salt electrolysis treatment may be insufficient compared to other portions. Is desirable. Further, as a pre-stage of performing the neutral salt electrolysis treatment, for example, it is also desirable in some cases to perform a pickling treatment using a HF / HNO ₃ solution, which makes it possible to improve the descaling efficiency,
Alternatively, in the same manner as the previous step, it is also possible to perform anode electrolysis using the stainless steel wire side as the cathode and then perform cathode electrolysis using the stainless steel wire side as the anode. By performing the neutral salt electrolysis treatment, it becomes possible to efficiently perform descaling of the stainless steel wire rod which is difficult to descale.

Furthermore, in some cases, as a post-stage of the neutral salt electrolysis treatment, for example, post-pickling using an HF / HNO ₃ solution can be carried out, and the neutral salt electrolysis treatment can be used to remove the acid. When there is no scale, it is possible to further improve the descaling efficiency by subsequent pickling.

[0023]

The method for descaling a coil-shaped stainless steel wire according to the present invention has the above-mentioned constitution. Therefore, trivalent chromium is transformed into hexavalent chromium by the neutral salt electrolytic treatment. It becomes easy to be descaled, the descaling is done by using inexpensive neutral salt, and the energy consumption unit is low because it is not necessary to raise the salt bath temperature as much as the conventional salt treatment. The maintenance cost will be low, and since it uses neutral salt, it will not cause pollution.

Further, since the neutral salt electrolysis treatment according to the present invention is such that the scale is altered by the reaction of exchange of electrons accompanied by hydrolysis, there is no erosion of the metal and the surface after electrolysis treatment is not eroded. The skin quality is remarkably good.

Then, by connecting the stainless steel wire to the anode through the coiled stainless steel wire hanging device wound in a coiled state, the anode connection to the stainless steel wire becomes extremely easy. Especially, when the stainless steel wire is rotated in the circumferential direction of the coil, the anode connection to the stainless steel wire becomes extremely simple. Of course, for example, when two or more rotating rollers are installed in a neutral salt bath and the coiled stainless steel wire is placed on the two or more rotating rollers, the coil rotates in the circumferential direction. And the anode connection can be performed well.

Further, in the case of a hard-to-descale stainless steel wire rod, the treatment time is extended, or a minus-to-plus electrolysis treatment, that is, an anode electrolysis with the stainless steel wire rod side as the cathode is performed as a pre-stage, and then the stainless steel By carrying out an electrolytic treatment in which cathode electrolysis is performed with the wire side serving as an anode, descaling can be performed even better.

Further, by providing a cathode in the vicinity of at least one or both of the coil outer peripheral side and the coil inner peripheral side of the coiled stainless steel wire rod, efficient and uniform descaling can be performed,
Particularly, by providing the cathodes both on the outer circumference side of the coil and on the inner circumference side of the coil, more uniform descaling is performed.

By adjusting the temperature of the neutral salt bath to 70 to 90 ° C. and setting the current density in the range of ³ to 10 A / dm ² , the neutral salt electrolytic treatment is carried out stably and efficiently. 10 to 30% as a neutral salt bath
The use of a concentration of sodium sulphate results in a good descaling treatment at low cost.

Furthermore, by rotating the coiled stainless steel wire rod in the circumferential direction during the neutral salt electrolytic treatment, the upper part of the coiled stainless steel wire rod located on the upper surface side of the treatment tank is also rotated. By approaching the cathode on the bottom surface or the side surface of the tank, the scale can be reformed favorably, the descaling property is improved, and unevenness in descaling hardly occurs.

Further, the coiled stainless steel wire is dipped in a neutral salt bath, and as a previous step, anode electrolysis is performed with the stainless steel wire side as the cathode, and then cathode electrolysis with the stainless steel wire side as the anode. This makes it possible to deal with descaling of hard-to-scale steel wires.

[0031]

1 and 2 show an embodiment of a descaling apparatus used for carrying out the descaling method for a coiled stainless steel wire according to the present invention. The wire rod descaling device 1 includes a neutral salt bath 3 for accommodating a neutral salt bath 2 and a coiled stainless steel wire rod 4 wound in a coil state in a suspended state to form a coil in the neutral salt bath 2. 5 for immersing the rod-shaped stainless steel wire 4, electrodes 6, 7 respectively arranged on the coil outer peripheral side and the coil inner peripheral side of the coiled stainless steel wire 4 immersed in the neutral salt bath 2, and the suspender 5 has a structure in which a direct current power source 8 is connected to which an anode is connected via a conductive line 8a and electrodes 6 and 7 are connected to a cathode via a conductive line 8b.

In this embodiment, the electrode 6 arranged on the outer peripheral side of the coil has a concave cross section, and the electrode 7 arranged on the inner peripheral side of the coil has a O cross section.

In this embodiment, the coil-shaped stainless steel wire 4 is made of 17% Cr ferritic stainless steel (SUS430; C: 0.05%, Si: 0.30).
%, Mn: 0.50%, P: 0.04%, S: 0.01
%, Cu: 0.50%, Ni: 0.30%, Cr: 1
7.00%, N: 0.025%, balance Fe and impurities).

As the neutral salt constituting the neutral salt bath 2, sodium sulfate (Na ₂ SO ₄ ) having a concentration of 20% was used and the temperature was set to 80 ° C.

The suspending tool 5 is connected to the anode of the DC power source 8 through the conductive wire 8a so that the anode can be applied to the coiled stainless steel wire 4 suspended by the suspending tool 5. In addition, the hanger 5 is partially (for example, in a portion of the upper surface with which the wire is in contact) electrically conductive, or is entirely electrically conductive.

Further, the electrode 6 arranged on the outer peripheral side of the coil of the coil-shaped stainless steel wire 4 is formed of a copper plate in a concave cross-section, and the electrode arranged on the inner peripheral side of the coil of the coil-shaped stainless steel wire 4. No. 7 is formed of a copper plate with a cross section of O shape.

Therefore, when the oxide scale (Cr ₂ O ₃ etc.) formed on the surface of the coiled stainless steel wire rod 4 wound in the coil state is removed,
The temperature of the neutral salt bath 2 in the neutral salt bath 3 is set to 80 ° C., and the coiled stainless steel wire 4 is hung on the suspending tool 5 to be transported and immersed in the neutral salt bath 2 before immersion. Energize the cathode side of the DC power supply 8 to the electrode 7 inserted in the inner circumference side of the coil and the electrode 6 installed in the neutral salt bath 3 and energize the coiled stainless steel wire 4 to the anode side of the DC power supply 8. Then, the neutral salt electrolysis treatment is performed while controlling the current density to be 6 A / dm ² .

After the neutral salt electrolysis treatment with the electrolysis treatment time of about 120 sec is completed, the voltage supply from the DC power source 8 is stopped, and the coiled stainless steel wire 4 is pulled up by the suspending tool 5.

When the surface of the stainless steel wire rod was observed after the neutral salt electrolytic treatment was completed in this way,
Conventional caustic soda (NaOH) and sodium nitrate (NaNO)
It had a good surface skin quality comparable to the high temperature salt treatment using ₃ ).

Further, when it was examined by X-ray diffraction whether or not the scale was altered by the electrolytic treatment, hexavalent chromium of M ₂ CrO ₄ or MCr ₂ O ₇ was formed after the electrolytic treatment. Was confirmed to have been altered.

FIG. 3 and FIG. 4 show an example of the construction of a suspension 5 having a coiled stainless steel wire rod rotation drive mechanism. The suspension 5 comprises a cross beam 11a and an L-shaped member 1
1b is provided with a suspender main body 11 which is rotatably provided with a coil-shaped stainless steel wire rod supporting rotary roll 13 via bearings 12a and 12b. A sprocket 15 fixed to the rotating shaft 14a of the motor 14 with a reduction mechanism installed on the upper surface.
A chain 17 is hung between the sprocket 16 and the sprocket 16 fixed to the end of the rotating roll 13, and the rotating roll 13 is rotated by rotationally driving the motor 14 with a reduction mechanism, whereby the maximum coil width W The coiled stainless steel wire 4 may be made to rotate so that descaling by neutral salt electrolytic treatment can be performed uniformly.

[0042]

EFFECTS OF THE INVENTION According to the descaling method for a coiled stainless steel wire according to the present invention, since it has the above-mentioned constitution, it is possible to transform trivalent chromium into hexavalent chromium by electrolytic treatment with neutral salt. Therefore, it is possible to make it easy to descale, and it is possible to use inexpensive neutral salt, so it is possible to lower the unit consumption of raw material and raise the temperature to the same level as the conventional salt treatment. It is possible to reduce the energy consumption rate because it is not necessary, and it is possible to reduce the maintenance cost.Because neutral salts are used, there is no need to worry about pollution. It is possible to achieve high efficiency, low cost, improvement of skin quality, and descaling of stainless steel wire without pollution, which is a remarkable effect.

By connecting the stainless steel wire to the anode through the coiled stainless steel wire suspender, the anode can be applied to the stainless steel wire with a remarkably simple structure. Excellent effect is brought about.

Further, by providing a cathode in the vicinity of at least one or both of the coil outer peripheral side and the coil inner peripheral side of the coiled stainless steel wire, the neutral salt electrolytic treatment of the coiled stainless steel wire can be uniformly performed. It has an excellent effect that it can be performed efficiently.

By setting the temperature of the neutral salt bath to 70 to 90 ° C. and the current density to 3 to 10 A / dm ² , it is possible to perform a good neutral salt electrolysis treatment. Is brought about.

Further, as a neutral salt constituting the neutral salt bath, 1
By using an aqueous solution of sodium sulfate having a concentration of 0 to 30%, the excellent effect that the neutral salt electrolytic treatment can be efficiently descaled at low cost is brought about.

Furthermore, since the coil-shaped stainless steel wire rod descaling apparatus according to the present invention has the above-mentioned configuration, the coil-shaped stainless steel wire rod descaling method according to the present invention can be easily implemented. That is, a remarkably excellent effect is brought about.

[Brief description of drawings]

FIG. 1 is an explanatory view of a descaling apparatus for a coil-shaped stainless steel wire according to an embodiment of the present invention as viewed from a side surface side of a coil.

FIG. 2 is an explanatory view of the descaling device for a coiled stainless steel wire according to an embodiment of the present invention as viewed from the coil end face side.

FIG. 3 is an explanatory view of a suspender including a coil-shaped stainless steel wire rod rotation drive mechanism.

FIG. 4 is a side view of FIG.

[Explanation of symbols]

1 Descaling Device for Coiled Stainless Steel Wire 2 Neutral Salt Bath 3 Neutral Salt Bath 4 Coiled Stainless Steel Wire 5 Lifting Tool 6 Electrode 7 Electrode 8 DC Power Supply 13 Coiled Stainless Steel Wire Roll Support Roll (Coiled Stainless Steel Steel wire rod rotation drive mechanism) 14 Motor with reduction mechanism (coiled stainless steel wire rod rotation drive mechanism)

Claims (12)

[Claims] 1. A coiled stainless steel wire rod wound in a coiled state is immersed in a neutral salt bath so that the coiled stainless steel wire rod side serves as an anode and a cathode is provided in the vicinity of the coiled stainless steel wire rod. A method for descaling a coiled stainless steel wire rod, which comprises removing the scale on the surface of the stainless steel wire rod by electrolytically treating with a neutral salt. 2. The method for descaling a coiled stainless steel wire rod according to claim 1, wherein the stainless steel wire rod is connected to the anode via a coiled stainless steel wire rod suspender. 3. The descaling method for a coiled stainless steel wire rod according to claim 1, wherein a cathode is provided on at least one of the coil outer circumference side and the coil inner circumference side of the coiled stainless steel wire rod. 4. The method for descaling a coiled stainless steel wire rod according to claim 1, wherein the neutral salt bath is treated at 70 to 90 ° C. for electrolytic electrolysis of the neutral salt. 5. The method of descaling a coil-shaped stainless steel wire according to claim 1, wherein the neutral salt electrolysis treatment is performed at a current density of 3 to 10 A / dm ² . 6. The neutral salt electrolysis treatment using a 10 to 30% concentration sodium sulfate aqueous solution as the neutral salt bath.
6. The method for descaling a coiled stainless steel wire according to any one of 1 to 5. 7. The method for descaling a coiled stainless steel wire according to claim 1, wherein the coiled stainless steel wire is rotated in the circumferential direction during the neutral salt electrolytic treatment. 8. The method for descaling a coiled stainless steel wire rod according to claim 1, wherein the rolled stainless steel wire rod and / or the annealed stainless steel wire rod is immersed in a neutral salt bath. 9. A coil-shaped stainless steel wire rod is immersed in a neutral salt bath, and as a previous step, an anodic electrolysis treatment is performed with the stainless steel wire rod side as a cathode, and then a cathode electrolysis treatment with the stainless steel wire rod side as an anode. Claim 1 thru | or 8 which perform
The method for descaling a coiled stainless steel wire according to any one of 1. 10. A neutral salt bath for accommodating a neutral salt bath, a hanger for immersing a coiled stainless steel wire wound in a coil state in the neutral salt bath, and a neutralizer. An electrode provided on at least one of the coil outer circumference side and the coil inner circumference side of the stainless steel wire immersed in the salt bath, and a DC power supply for connecting the anode to the stainless steel wire and the cathode to the electrode A descaling device for coiled stainless steel wire rods. 11. The descaling device for a coiled stainless steel wire rod according to claim 10, wherein the coiling stainless steel wire rod rotary drive mechanism is provided on the suspending device for rotating the coiled stainless steel wire rod in the circumferential direction thereof. . 12. The electrode connected to the cathode is an electrode having a concave or U-shaped cross section with an open upper portion, which is arranged on the outer peripheral side of the coil of stainless steel wire, and is arranged on the inner peripheral side of the coil of stainless steel wire. The descaling device for a coil-shaped stainless steel wire rod according to claim 10 or 11, further comprising an electrode having a cross-sectional o shape.