JPH02185998A - Method and apparatus for manufacturing one side face colored stainless steel strip - Google Patents

Abstract

PURPOSE:To dissolve colored film at one side face and to improve weldability by executing cathodic electrolytic treatment to the one side of a both-surfaces colored stainless steel strip and anodic electrolytic treatment to the other side face in mixed water solution of sulfuric acid or phosphoric acid and chromic acid. CONSTITUTION:The stainless steel strip S is passed through a coloring vessel 2 including the coloring bath 1 composed of the mixed water solution of the sulfuric acid and chromic acid (salt) to form the colored film on both surfaces. Successively, this is carried to an electrolytic treating vessel 6 through washing device 3 and dipped into the electrolytic treating liquid 5 composed of the mixed water solution of the sulfuric acid or the phosphoric acid and the chromic acid. The surface layer part of the steel strip S' faced to the anodic electrode plate 9 side is acted as the cathode with polarizing action, and by receiving the cathodic electrolytic treatment, the hardening treatment is executed to the colored film. The surface layer part of the steel strip S' faced to the cathodic electrode plate 10 side is acted as the anode, and by receiving the anode electrolytic action, the colored film is dissolved and removing and the one side face colored stainless steel strip S'' is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is capable of obtaining a single-sided colored stainless steel strip with excellent weldability, and furthermore, it is possible to obtain a single-sided colored stainless steel strip with excellent weldability, and furthermore, it is possible to obtain a single-sided colored stainless steel strip with excellent weldability. The present invention relates to a method for manufacturing a stainless steel strip that is colored on one side by a chemical coloring method, which can eliminate scratches on the surface of the strip, and an apparatus for carrying out the method.

[Conventional technology]

In recent years, colored stainless steel sheets with excellent design effects and excellent corrosion resistance have come into widespread use as building materials, kitchen equipment, and decorations.

There have been various methods for manufacturing colored stainless steel sheets, including the chromium/sulfuric acid method and the molten salt method.

Coloring methods using chemical coloring treatments such as the temper color method are widely practiced on an industrial scale. Among them, the chromium/sulfuric acid method has been used in recent years because it is easy to obtain a wide variety of stable color tones.
It is starting to be implemented.

This method of manufacturing colored stainless steel sheets using the chromium/sulfuric acid method involves immersing the stainless steel sheet in a coloring bath consisting of a mixed aqueous solution of high-temperature sulfuric acid and chromic acid or chromate, thereby coloring the surface layer of the stainless steel sheet through a chemical reaction. This is a method of forming a film, and its practical use has rapidly progressed since the International Nickel Company of the United Kingdom disclosed its coloring control method in JP-A-48-11243. This method of manufacturing colored stainless steel sheets using the chromium/sulfuric acid method was initially a so-called batch method for steel sheets, but in recent years, a continuous manufacturing method using steel strips has been introduced to improve productivity and reduce manufacturing costs. is transitioning to.

The colored film as formed by this method is porous and mainly composed of chromium oxide, and therefore has low wear resistance and low stain resistance. Therefore, as a method to eliminate this drawback, Japanese Patent Publication No. 53-31817 and Japanese Patent Publication No. 56-24
As shown in Publication No. 040, after a colored film is formed on the surface of a stainless steel strip, the colored stainless steel strip is placed as a cathode in an electrolytic treatment bath consisting of sulfuric acid or a mixed aqueous solution of phosphoric acid and chromic acid. A method of curing a colored film is carried out by carrying out a cathodic electrolytic treatment using, for example, a lead electrode placed in an electrolytic treatment bath as an anode. In other words, in this method, chromic acid in the electrolytic treatment solution is electrolytically reduced in the surface layer of the colored stainless steel strip, which is the cathode, to form chromium oxide or chromium water, which is the same as the colored film, in the porous part of the colored film. Sealing treatment is performed by depositing oxide to provide corrosion and wear resistance.

This method forms a stable colored film with excellent stain resistance. In such a method, when obtaining a double-sided colored stainless steel strip product, anodes are installed on both sides of the passing surface of the stainless steel strip, and both sides of the stainless steel strip are electrolytically treated to harden, and then one side is colored. When obtaining stainless steel strip products, corrosion resistance of the colored film on one side, which is a colored surface that does not need to be used, is not required; rather, it should be used as a colored surface because there are problems such as reduced weldability after it is manufactured. A method has been implemented in which an anode is installed only on one side and only that side is subjected to electrolytic treatment and hardening treatment.

[Problem to be solved by the invention]

However, among the methods for producing colored stainless steel strips as described above, the method for producing a single-sided colored stainless steel strip has the following problems.

That is, in the manufacturing process of colored stainless steel strip,
The finishing process that follows the coloring process (skin bath).

slitter process, etc.), but single-sided colored stainless steel strips do not undergo hardening treatment for the colored film on the colored surface, which is the side that does not need to be used. This colored film peels off due to friction with the roll, adheres to the roll surface, stains the roll, and causes uneven coloring and scratches due to the deposits on the colored surface that does not need to be used. there were.

In addition, the obtained colored stainless steel strip is made into a product by various processes such as welding in the next process or by the user, but even if it is a single-sided colored stainless steel strip, one side that is not usable is also hardened. Since an untreated colored film is formed, there is a problem of reduced weldability during processing, which is a common drawback of two-colored stainless steel strips. For example, T.I.
In fusion welding such as G welding, it is possible to weld under almost the same conditions as ordinary colorless stainless steel (welding current, welding density), but in resistance welding such as spot welding and seam welding, electrical insulation When electricity is passed through a colored film, the contact resistance is high, so sparks are generated, which can lead to melting of the welded part or incomplete welding (However, even in spot welding and seam welding, If the basic welding conditions of welding current, welding time, and pressure are selected, welding may be possible, although the conditions are much narrower than for ordinary uncolored stainless steel). Also, a characteristic of chemical coloring methods is that the color tone varies depending on the thickness of the colored film, but the thicker the colored film, the higher the contact resistance.
In the case of resistance welding, as this film becomes thicker, the pressure increases.

There was a drawback that it was necessary to lower the welding current.

Therefore, in the present invention, a stainless steel strip is immersed in a coloring bath made of a mixed aqueous solution of sulfuric acid and chromic acid or chromate, and then electrolytically treated in an electrolytic treatment bath made of a mixed aqueous solution of sulfuric acid or phosphoric acid and chromic acid. A single-sided colored stainless steel strip that prevents staining of the roll surface and occurrence of scratches on the stainless steel strip during the finishing process that follows the coloring process when producing a single-sided colored stainless steel strip, and has excellent weldability. An object of the present invention is to provide a method for producing a stainless steel strip that is colored on one side and an apparatus that can industrially carry out the method.

[Means to solve the problem]

As a result of various studies to achieve the above object, the present inventors have discovered the principle of hardening the colored film by electrolytically treating a colored stainless steel strip in an electrolytic treatment bath consisting of a mixed aqueous solution of sulfuric acid or phosphoric acid and chromic acid. Utilizing the opposite effect, a stainless steel strip is immersed in a coloring bath consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate to form a colored film on both sides, and then the stainless steel strip is colored on both sides. Place the cathode electrode plate on one side where the colored film will not be cured,
They completed the present invention by discovering that if the surface of the colored stainless steel band itself, which is not subjected to hardening treatment, is subjected to anodic electrolytic treatment using the surface itself as an anode electrode plate, the colored film will dissolve on that surface.

Hereinafter, a method for manufacturing a single-sided colored stainless steel fR band according to the present invention will be explained in detail based on the drawings.

FIG. 1 is a process schematic diagram showing one embodiment of the method for manufacturing a single-sided colored stainless steel strip according to the present invention.

In the drawings, S is an uncolored stainless steel strip, S' is a double-sided colored stainless steel strip, and S' is a single-sided colored stainless steel strip.

1 is a coloring bath consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate prepared in a coloring tank 2 in order to form a colored film on both sides of the uncolored stainless steel strip S; 3 is a coloring tank 2 A cleaning device 4 is installed on the inlet and outlet sides of the cleaning device 3 to remove the coloring bath 1 adhering to the double-sided colored stainless steel strip S' after passing through the coloring bath 1 inside. 5 is an electrolytic treatment bath made of a mixed aqueous solution of sulfuric acid or phosphoric acid and chromic acid prepared in the electrolytic treatment M2C, and 7 is an electrolytic treatment bath 5 in the electrolytic treatment tank 6. A dipping roll 8 is a DC power supply for electrolysis, and 9 is a roll made of lead dioxide, platinum, etc. installed in the electrolytic treatment bath 5. The roll is connected to the positive electrode of the DC power supply 8 for electrolysis, and serves as an anode. The active anode electrode plate 10 is made of titanium, stainless steel, etc. and is placed in the electrolytic treatment bath 5, and is placed on the opposite side of the anode electrode plate 9 and the double-sided colored stainless steel strip S', and is connected to a DC power source for electrolysis. The cathode electrode plate 9 is connected to the negative electrode of 8, and the cathode electrode plate 9 acts as a cathode. This is a brush roll that contains abrasive grains.

In the manufacturing process of the single-sided colored stainless steel strip having the above-mentioned configuration, first, the uncolored stainless steel strip S is coated in the colored bath 1.
The stainless steel strip S' is dipped and passed through overlapping dipping rolls into the coloring bath 2 in which the stainless steel strip is prepared, and a double-sided colored stainless steel strip S' is formed with a colored film on both sides. Next, the coloring bath 1 adhering to the surface of the double-sided colored stainless steel mis' is removed by washing with water in a cleaning device 3, and the plate is sent to an electrolytic treatment tank 6 by a feeding roll 4, and electrolyzed by dipping rolls 7 before and after it. The electrolytic treatment is performed while immersed in the treatment bath 5. Here, an anode electrode plate 9 connected to the positive electrode of the DC power supply 8 for electrolysis
The surface layer of the double-sided colored stainless steel @s' facing the side acts as a V cathode due to the splitting action, and as a result, the colored film on the surface layer of the double-sided colored stainless steel strip S' on the anode electrode plate 9 side is exposed to the electrolytic treatment bath. 5, which undergoes cathodic electrolytic treatment and hardening treatment.

On the other hand, the double-sided colored stainless steel '4FFS' faces the cathode electrode plate 10 side, which is placed on the opposite side of the anode electrode plate 9 and the double-sided colored stainless steel strip S' and is connected to the negative electrode of the DC power source 8 for electrolysis. Similarly, the surface layer of S' acts as an anode due to the branching action, and as a result, the double-sided colored stainless steel strip S'
The colored film on the surface layer on the side of the cathode electrode plate 10 is coated with the electrolytic treatment bath 5.
Inside, it undergoes anodic electrolytic treatment and is dissolved and removed, forming a single-sided colored stainless steel strip S.

In addition, during this cathodic and anodic electrolytic treatment, in order to sufficiently dissolve the colored film on the surface of the double-sided colored stainless steel strip S' and harden the colored film, the current density should be set at 0.5 to 30 A.
It is desirable to set it in the range of /d and l.

This has a current density of 30 A/drr? This is because if it is higher than 1, chromium metal will precipitate on the hardened surface, which is not preferable, and the most preferable range is 1 to IOA/di. It is desirable that the electrolytic treatment time be at least 2 minutes or more, and the material of the electrode used for the electrolytic treatment is not particularly limited as long as it has corrosion resistance to the electrolytic treatment solution, but lead dioxide, platinum, etc. are suitable for the anode. Titanium and stainless steel are suitable for the cathode.

Thereafter, the surface of the thus obtained single-sided colored stainless steel strip S'' that has been subjected to the anodic electrolytic treatment is further polished as necessary by a brush roll 11 containing abrasive grains that rotates in contact with this surface. The plate is then sent to the next finishing process.

Next, FIG. 2 shows an example of the arrangement of electrode plates and double-sided colored stainless steel strips in an electrolytic treatment tank suitable for carrying out the method of the present invention on stainless steel strips of various widths. This will be explained using a perspective view shown in FIG.

The anode electrode plate 9 and the cathode electrode plate 10 have a rectangular shape longer than the width of the double-sided colored stainless steel strip S', and the anode electrode plate 9 is placed on one side facing the threading surface of the double-sided colored stainless steel strip S'. In addition, this anode electrode plate 9 and the double-sided colored stainless steel strip S
Cathode electrode plates 10 are placed on opposite sides of the electrode 10, and both ends of the cathode plates 10 are insulated from each other by pins 13 made of an insulating material via an insulator 12 outside the electrolytic bath 5 of the electrolytic treatment tank 6. There are nine pin joints. Furthermore.

The plurality of sets of both types of electrode plates 9 and 10 are pin-jointed by the pins 13 to the electrode plate connecting members 14 which are arranged on both sides of the electrolytic treatment tank 6 in parallel with the direction of passing of the double-sided colored stainless steel strip S'. ing. Also, this electrode plate connecting material 1
4 is a horizontal member that is rotated about a shaft 17 that is located at the center of the passing surface of the double-sided colored stainless steel strip S' and is provided on the inlet and outlet sides of the electrolytic treatment tank 6. 15 is pin jointed at each end with pin 16.

The horizontal member 15 and the electrode plate connecting member 14 constitute a link mechanism in which they are connected in a parallelogram shape by pins 16.

With this configuration, the horizontal member 15 rotates around the shaft 17.
When rotated, the electrode plate connecting members 14 located on both sides of the electrolytic treatment tank 6 parallel to the passing direction of the double-sided colored stainless steel strip S' are aligned with each other in the passing direction of the double-sided colored stainless steel strip S'. In order to move in the opposite direction, this electrode plate connecting member 1
Anode electrode plate 9 pin jointed to 4 with pin 13
And the cathode electrode plate 10 rotates parallel to the double-sided colored stainless steel strip S' about the central position of the through-surface of the double-sided colored stainless steel strip S'. In addition, the surface electrode plate 9
and 10 are masked with an insulator 18 except for the surfaces projected on the double-sided colored stainless steel strip S', problems such as current density changes and current wraparound can be solved, and the anode electrode plate 9 and the cathode electrode plate Even if the plate width of the double-sided colored stainless steel strip S' changes, the electrolytic surface length of 10 can be accommodated, making uniform electrolytic treatment possible.

[For production]

As described above, in the method for manufacturing a single-sided colored stainless steel strip according to the present invention, double-sided colored stainless steel is immersed in a colored bath 1 consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate to form a colored film. The colored film on one surface layer of the band S' is formed by cathode electrolysis by a current flowing between the anode electrode plate 9 connected to the positive electrode of the DC power source 8 for electrolysis and one surface layer of the double-sided colored stainless steel band S'. Processed and hardened. In other words, the chromic acid in the electrolytic treatment solution is electrolytically reduced in the surface layer of the double-sided colored stainless steel strip S', which serves as a cathode, and chromium oxide and chromium hydroxide, which are the same as the colored film, are formed in the porous parts of the colored film. A pore sealing treatment (hardening treatment) is performed by the deposition of , thereby forming a stable colored film with corrosion resistance, abrasion resistance, and stain resistance.

On the other hand, the colored film on the other surface layer of the double-sided colored stainless steel strip S' is formed between the cathode electrode plate 10 connected to the negative electrode of the DC power source 8 for electrolysis and the other surface layer of the double-sided colored stainless steel strip S'. A flowing electric current causes the anodic electrolytic treatment, which has the opposite effect to the cathodic electrolytic treatment described above, to dissolve the colored film mainly consisting of chromium oxide and chromium hydroxide in the acidic Cry3 aqueous solution constituting the electrolytic treatment bath 5. It will be removed.

Further, one side of the double-sided colored stainless steel strip S' from which the colored area film has been dissolved and removed as described above may be left as is, but it may be physically polished off using the brush roll 11 containing abrasive grains afterwards. This makes it possible to construct a surface with good electrical conductivity without any colored film. Note that it is preferable to perform physical polishing removal after chemical dissolution and removal treatment in this way to ensure that one side of the stainless steel strip is completely free of any colored film. Since the amount of colored film powder produced is significantly smaller than when the colored film is removed by polishing, this method is more preferable in terms of management efficiency, workability, and prevention of environmental deterioration.

Furthermore, according to the apparatus of the present invention, the method of the present invention described above can be carried out. In particular, when the electrolytic cell 6 having the structure shown in FIG. 2 is used, the anode electrode plate 9 and the cathode electrode plate 10 are connected to each other. A horizontal member 15 is pin-jointed to the electrode plate connecting member 14 with a pin 13 and pin-jointed to the ends of the electrode plate connecting member 4 with a pin 16 to form a parallelogram-shaped link mechanism with the electrode plate connecting member 14. By rotating around the shaft 17, the anode electrode plate 9 and the cathode electrode plate lO
can be rotationally moved relative to the running direction of the double-sided colored stainless steel strip S', and as a result, it is possible to change the electrolytic surface length in the width direction of the double-sided colored stainless steel strip S'. Even if the plate width of ' changes, it becomes possible to adapt to the change. This also solves problems such as current density changes and current wrap-around, making it possible to perform uniform electrolytic treatment.

[Example 1] Using the apparatus shown in FIGS. 1 and 2 without using the brush roll 11 that contains abrasive grains, uncolored stainless steel mN'! fFS
BA finishing material of US 304 (plate thickness 20.4 strokes, plate width:
1030■) was immersed in a coloring bath 1 consisting of a mixed aqueous solution of sulfuric acid and chromic acid to obtain a deep golden double-sided colored stainless steel strip S'. Next, this double-sided colored stainless steel strip S
As a result of electrolytically treating S' in an electrolytic treatment bath 5 consisting of a mixed aqueous solution of phosphoric acid and chromic acid at a current density of 5 A/di, the surface layer of the double-sided colored stainless steel strip S' on the anode electrode plate 9 side is In the treatment bath 5, the material is subjected to cathodic electrolytic treatment to be hardened and turned red, and the surface layer on the one side of the cathode electrode plate 10 is subjected to anodic electrolytic treatment in the electrolytic treatment bath 5 to dissolve and remove the colored film. Although some blue unevenness remained, most of the surface was silvery-white normal stainless steel #FS.

The thus obtained single-sided colored stainless steel strip S'' was subjected to a refining process (skin pass, slitter process, etc.) to produce a single-sided colored stainless steel plate.At this time, the adhesion of a colored film to the roll surface during each refining process The weldability of the single-sided colored stainless steel plate was good.

[Example 2] The same uncolored stainless steel strip S as in Example 1 was prepared based on the apparatus shown in Figs. 1 and 2 and using a brush roll 11 containing abrasive grains (reduction amount lMn1 rotation speed 2000 rpm). Coloring treatment, electrolytic treatment, and refining depending on the processing conditions.

Cutting and the like were performed to obtain a single-sided colored stainless steel plate S'. In this single-sided colored stainless steel strip S#, the colored film on the surface layer that had been subjected to the anodic electrolytic treatment was completely removed, and no colored film was observed to adhere to the roll surface during each refining process. Furthermore, the weldability of the single-sided colored stainless steel sheet was very good.

〔Effect of the invention〕

As detailed above, the method for producing a stainless steel strip colored on one side according to the present invention involves immersing the stainless steel strip in a coloring bath consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate, After forming a colored film on
By cathodic electrolyzing one side and anodic electrolyzing the other side at the same time, the colored side of the cathodic electrolytically treated side becomes a surface with corrosion resistance and wear resistance after being hardened, making it more durable than other anodic electrolytically treated surfaces. The colored film on one side is dissolved and removed, leaving almost a normal stainless steel strip fabric.

As a result, it is possible to prevent colored films peeled off from the stainless steel strip from adhering to the surfaces of various rolls in the process after cathodic electrolytic treatment, that is, hardening of colored surfaces, and to prevent harmful effects caused by the presence of these peeled colored films. Not only that, but the weldability of the obtained single-sided colored stainless steel sheet is improved because the non-colored side serves as the cloth for a normal stainless steel strip.

In addition, if following the above method, the colored film is further polished and removed by rotating a brush roll containing abrasive grains on one side that has been subjected to anodic electrolytic treatment, the above-mentioned book can be removed without producing a large amount of colored film powder. It is possible to improve the effects of the invented method.

Furthermore, the apparatus of the present invention is an apparatus for effectively carrying out the method of the present invention having the above-mentioned advantages, and in particular, the electrolytic treatment tank having the structure shown in FIG. Since the stainless steel strip is configured to be able to change in the width direction, even if the width of the colored stainless steel strip changes, it can be accommodated, and uniform electrolytic treatment becomes possible.

As described above, the present invention has great effects,
Its industrial value is enormous.

[Brief explanation of the drawing]

Fig. 1 is a process schematic diagram showing one embodiment of the method for producing a single-sided colored stainless steel strip according to the present invention, and Fig. 2 shows the arrangement of the electrode plate and the double-sided colored stainless steel strip in the electrolytic treatment tank shown in Fig. 1. FIG. In the drawings 1...Coloring bath 2...Coloring tank 3...Cleaning device 4...Feeding plate roll 5...Electrolytic treatment bath 6...Electrolytic treatment tank 7... ... Immersion roll 8 ... DC power supply for electrolysis 9 ... Anode electrode plate 10 ... Cathode electrode plate 11 ... Brush roll 12 for containing abrasive grains ... Insulator 13 ... ...Pin 14...11ipf! Plate connecting material 15...Horizontal member J6...Pin 17...Shaft 18...Insulator S...Uncolored stainless steel strip S'...Both sides colored stainless steel Band S''・・・Single side colored stainless steel band Patent applicant: Nissin Steel Co., Ltd.

Claims (1)

[Scope of Claims] 1. A double-sided colored stainless steel strip, which is obtained by immersing a stainless steel strip in a colored bath consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate to form a colored film, is treated with sulfuric acid or phosphoric acid and chromium salt. A method for manufacturing a single-sided colored stainless steel strip, characterized in that one side is cathodic electrolytically treated and the other side is simultaneously anodic electrolytically treated in an electrolytic treatment bath consisting of an aqueous solution mixed with an acid. 2 Cathode and anodic electrolysis treatment at a current density of 0.5 to 30 A/
The method for producing a single-sided colored stainless steel strip according to claim 1, which is carried out under conditions of dm^2. 3. The method for manufacturing a single-sided colored stainless steel strip according to claim 1 or 2, wherein the one side subjected to the anodic electrolytic treatment is further polished by contacting and rotating a brush roll containing abrasive grains. 4. A coloring tank (2) in which a coloring bath (1) consisting of a mixed aqueous solution of sulfuric acid and chromic acid or chromate is prepared in which the stainless steel strip (S) is immersed to form a colored film on both the front and back sides. An electrolytic treatment bath (5) consisting of a mixed aqueous solution of sulfuric acid or phosphoric acid and chromic acid is prepared in which the double-sided colored stainless steel strip (S') drawn out from the coloring tank (2) is immersed. The electrolytic treatment tank (6) is equipped with an anode electrode plate (
9) is also provided with a cathode electrode plate (10) on the opposite side of the anode electrode plate (9) and the double-sided colored stainless steel strip (S'). (10) and are respectively connected to the positive and negative electrodes of a DC power source (8) for electrolysis. 5 A double-sided colored stainless steel strip (S') in which the anode electrode plate (9) and the cathode electrode plate (10) are immersed and passed through the electrolytic treatment bath (5) of the electrolytic treatment tank (6).
), with both ends of the rectangle being longer than the width of the insulator (12) outside the electrolytic treatment bath (5) of the electrolytic treatment tank (6).
) are pin-jointed in an insulating state with a pin (13) made of an insulating material to form a set. ), both ends of which are attached to a horizontal member (15) which is rotated about a shaft (17) provided at the entrance and exit sides of the electrolytic treatment tank (6) at the center of the plate passing surface of the plate ( Electrode plate connecting member (14) pin-jointed at 16) and connected to the horizontal member (15) in a parallelogram shape.
5. The apparatus for producing a single-sided colored stainless steel strip according to claim 4, wherein the stainless steel strip is pin-jointed by the pin (13). 6. The single side according to claim 5, wherein both ends of both electrode plates (9) and (10) forming a surface other than the surface projected onto the double-sided colored stainless steel strip (S') are masked with an insulator (18). Equipment for producing colored stainless steel strips.