JPH07122151B2 - Method for producing stainless steel strip for chemical coloring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides an acid composed of a mixed acid of nitric acid and hydrofluoric acid after cold rolling whose surface finish is represented by No. 2D and No. 2B. In the chemical color development process, the stainless steel strip that has been pickled in the washing solution and is left cold-rolled as it is or is left in the state of being cold-rolled is immersed in a mixed aqueous solution of chromic acid and sulfuric acid. The present invention relates to a method for producing a stainless steel strip for chemical color development, which is produced so as not to generate an uneven pattern.

[Conventional technology]

In recent years, a chemically colored tinted stainless steel sheet having a high design effect and excellent corrosion resistance has been widely used for building materials, kitchen equipment and decoration.

Temper color method, molten salt method, and chromic acid / sulfuric acid method have been conventionally known as methods for coloring stainless steel, but in general, the chromic acid / sulfuric acid method, which is easy to obtain various color tones, has been widely industrialized. There is. This chromic acid / sulfuric acid method is a stainless steel plate or strip steel in a mixed aqueous solution of chromic acid and sulfuric acid (in the case of a stainless steel plate, it is a batch type treatment, and since the treatment is the same as that of a continuous type stainless steel strip, This is a coloring method that utilizes the phenomenon of light interference between this film and the base interface by dipping (a typical example of stainless steel strip below) to form an extremely thin oxide film on the surface. It is also characterized in that the color tone is considerably different depending on the finish even if the finish of the base is utilized at the same time as the hue is the same, and it is generally different from the coating method and plating method which are other coloring methods of stainless steel. It is also called the coloring method.

The chemical coloring method of stainless steel by the chromic acid / sulfuric acid method is a color control method (Japanese Patent Laid-Open No. 48-11243) and a hardening treatment method of a colored film (Japanese Patent Laid-Open No. 49-21339) by International Nickel Co. of the United Kingdom. Has been rapidly put into practical use since its development. That is, the greatest feature of this colored stainless steel strip is that, unlike the colored stainless steel strip by painting, the surface finish of the stainless steel strip is utilized as it is, and even if it is the same hue, its color tone and luster Since they are different, the taste can be made different depending on the purpose and use. For example, BA finishing materials (bright annealed finishing materials) have a glossy and vivid color tone, and BA finishing materials are buffed to give a highly reflective surface, and mirror finish materials have a glossier and vibrant color tone. In the case of polishing finish materials such as HL, No. 4 finish materials, it shows astringent color tone with suppressed gloss, and for finish materials leaving a pickled surface such as No. 2D materials and No. 2B materials. It has a dark and subdued color tone, and this No. 2
D Finishing materials that have a shot blasting surface to impart anti-glare properties give a deeper, astringent color tone.

Therefore, by using such colored stainless steel strips having different color tones for the purposes that match the respective color sensations, it is possible to manufacture products with high designability.

[Problems to be Solved by the Invention]

However, this chromic acid / sulfuric acid method is characterized in that the surface finish of the stainless steel strip is utilized as described above and that the color tone is different depending on the surface finish. Since this is a coloring method in which an extremely thin oxide film is formed on the surface of a stainless steel strip by oxidizing it with an oxidizing solution composed of an aqueous solution, uneven coloring will occur if there is a partial difference in the surface state of the stainless steel strip. It has a drawback that it is apt to occur. The partial difference in the surface condition of the stainless steel strip may be visually observable such as the difference in gloss and uneven polishing, but the difference in the partial surface activity and the remains of the deteriorated portion just below the scale may be In some cases, it cannot be visually confirmed.
Therefore, even if stainless steel having a completely uniform appearance by visual observation is used, a multicolor unevenness pattern may occur when the chemical color treatment is performed, which is a phenomenon that has been troublesome to the present inventors.

The following is a case where the stainless steel strip to be used for the production of the stainless steel strip for chemical coloring can and cannot be predicted from the visual judgment of the appearance of the steel strip to determine whether a color unevenness pattern will occur after the chemical coloring treatment. Enumerate.

<< When a color unevenness pattern can be predicted by visual appearance judgment >> When there is a partial difference in surface gloss for BA finishing materials and mirror finishing materials.

For HL finish material, No.4 finish material, if the surface has clear unevenness in polishing.

For No.2D and No.2B finishing materials, if the surface has a partial difference in gloss or a clear pickling pattern.

When there is a surface flaw (shaving, sliver, etc.) peculiar to stainless steel strip, general flaw (komi, bump, slip, oyster) or chatter mark, etc., regardless of the surface finish.

When the stainless steel strip having the surface quality defects as described above is subjected to the chemical color development treatment, a color unevenness pattern is surely produced.

<< When the appearance of color unevenness cannot be predicted by visual inspection of appearance >> When the grain size differs greatly in the strip width direction of the steel strip.

Is there a partial difference in the composition of the surface layer of the steel strip?
When there are many inclusions.

When there is a partial difference in the thickness of the passivation film on the surface of the steel strip.

When stains that cannot be visually confirmed are attached to the steel strip surface.

When there is a partial difference in the contact between the steel strip and rolls or pads in the steel strip manufacturing process.

For mirror-finished materials, when there is a partial difference in the number of buffing cycles during surface polishing or the degree of bubbling.

In the case of HL, No.4 finishing material, there is non-uniformity in the state of contact with the polishing belt, resulting in differences in the polishing depth and the temperature rise state during polishing.

No.2D and 2B finishes have a non-uniform effect on the surface of the pickling surface, because the pickling surface remains on the surface. If.

As enumerated above, it can be said that it is quite difficult to judge whether or not the color unevenness pattern is generated only by visually observing the surface condition of the stainless steel strip to be subjected to the chemical coloring treatment. For this reason, it is common to determine whether or not a color unevenness pattern occurs by trial-coloring the stainless steel strip.

Therefore, in order to obtain a chemically colored stainless steel strip having a uniform color tone without a color unevenness pattern, it is necessary to produce a stainless steel strip to be subjected to a chemical coloring treatment with a finish having a visually uniform finish. It is also an essential condition that the surface properties of the stainless steel strip are uniform. As described above, since the stainless steel strip subjected to the chemical color treatment uses a delicate chemical reaction, it is necessary to have a surface property higher than that of a general stainless steel strip other than those subjected to the chemical color treatment. Therefore, prior to the chemical color treatment, degreasing treatment for surface modification of stainless steel strip or light pickling treatment is disclosed in JP-A-58-199896 (stainless steel coloring treatment method). JP-B-58-221283 (stainless steel coloring pretreatment method), JP-B-61-264197 (stainless steel mirror-polishing plate coloring pre-treatment method), JP-B-62-24507 (coloring stainless steel plate manufacturing method), etc. However, the surface finish of the stainless steel strip to be subjected to the chemical coloring treatment is composed of a heat treatment and a mixed acid of nitric acid and hydrofluoric acid after cold rolling as represented by No. 2D and No. 2B. A stainless steel strip with a pickled surface that remains as it is or is cold-rolled after being pickled in a highly reactive pickling solution. No one posted a method to homogenize . Therefore, when the finishing material with the pickled surface remaining as described above is subjected to the chemical color development treatment with the conventional technique without any particular consideration, a color unevenness pattern is generated and the commercial value is lost, and the following problems occur. was there.

In the conventional technology, the uniformity of the color tone could not be confirmed unless the stainless steel strip to be subjected to the chemical coloring treatment was trial-colored. It was. Especially in the continuous coloring treatment, the yield was much larger because the apparatus was large-scale. Further, the productivity of this test coloring has been reduced.

Especially in the above-mentioned finishing material where the pickled surface remains,
The surface of the pickling solution is greatly affected by the cleaning method of the pickling solution after the pickling is completed.For example, when the amount of washing water is increased without consideration, the acid concentration in the pickling tank is reduced, Descaling failure will occur.

The non-uniformity of the surface properties of the stainless steel strip produced in the pickling process may or may not be visually confirmed. It cannot be modified by the pretreatment method.

Even in the production of general stainless steel strips other than those used for chemical coloring stainless steel strips, the stainless steel strips are dried during the pickling process during the pickling process in the annealing / pickling process. If it does, a pattern called acid burn may occur. This is because the pickling solution on the stainless steel strip evaporates due to the sensible heat of the steel strip and the concentration of the pickling solution increases, causing uneven corrosion of the surface of the stainless steel strip. Since it can be visually confirmed, it can be solved by the method shown in, for example, Japanese Patent Laid-Open No. 56-38481. However, even if this method is implemented, a sufficient effect can be obtained for the stainless steel strip for chemical coloring. There wasn't.

In the present invention, when the colored stainless steel strip is obtained by the chemical coloring treatment, the surface finish of the stainless steel strip is N
After cold rolling as represented by o.2D and No.2B, it is heat treated and then pickled in a pickling solution consisting of a mixed acid of nitric acid and hydrofluoric acid, either as it is or after cold rolling. Therefore, it is an object to prevent the phenomenon that a color uneven pattern is likely to occur in a stainless steel strip having a pickled surface.

[Means for Solving the Problems]

The present inventors have solved the above-mentioned drawbacks of the prior art, and when obtaining a colored stainless steel strip by a chemical coloring treatment, the surface finish of the stainless steel strip is cold as represented by No. 2D, No. 2B. Heat treatment after rolling and pickling treatment in a pickling solution consisting of nitric acid and hydrofluoric acid, and as it is or after cold rolling, the pickling surface remains, resulting in uneven color pattern on the stainless steel strip. As a result of investigating the cause of susceptibility to oxidation, the cause is not the coloring process of the stainless steel strip, but the reactive acid consisting of a mixed acid of nitric acid and hydrofluoric acid in the previous process of annealing and pickling the stainless steel strip. It was clarified that there is a cleaning method for the cleaning solution, and the necessary and sufficient descaling process was completed in the pickling process of the stainless steel strip, and immediately after being drawn from the pickling solution in the pickling tank via the semi-immersion roll. Stainless steel strip A plurality of internal mixing type two-fluid fine spray nozzles installed in the nozzle header facing the position away from the semi-immersion roll and the pickling solution were adjusted to the amount of evaporated water of the pickling solution in the pickling tank. A mist of water for cleaning and air is sprayed onto the semi-immersion roll and the stainless steel strip to wash and remove the pickling solution adhering to the stainless steel strip and to the stainless steel strip and bring it into the pickling tank. It prevents various stains such as rolling oil, abrasion powder during rolling, chemicals during pretreatment, etc. from adhering to the surface of the semi-immersion roll on the exit side and transferring to the drawn stainless steel strip, and It was clarified that the above problems can be solved by cooling the stainless steel strip and immediately and uniformly ending the descaling reaction of the stainless steel strip, and completed the present invention.

That is, the present invention is, after cold rolling, subjected to heat treatment and pickling treatment in a pickling solution consisting of a mixed acid of nitric acid and hydrofluoric acid, and in a mixed aqueous solution of chromic acid and sulfuric acid as it is or after cold rolling. When manufacturing the stainless steel strip to be supplied to the chemical color development step by immersing the stainless steel strip immediately after being pulled out from the pickling solution in the pickling tank through the semi-immersing roll, the semi-immersing roll and the acid From a plurality of internal mixing type two-fluid fine spray nozzles installed in the nozzle header facing away from the washing liquid, washing water and air having a water amount corresponding to the amount of evaporated water of the pickling liquid in the pickling tank And spraying the mist on the semi-immersion roll and the stainless steel strip to stop the reaction between the stainless steel strip and the pickling solution.

Hereinafter, a method for producing a stainless steel strip for chemical color development according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view of a continuous annealing pickling equipment for stainless steel strips including the method of the present invention, and FIG. 2 is a side cross section of a pickling tank for carrying out the method of the present invention in a continuous annealing pickling equipment for stainless steel strips. A schematic view, FIG. 3 is a perspective view for explaining the installation condition of the water washing device in FIG. 2, and FIG. 4 is a diagram showing the configuration of the water washing device,
FIG. 5 is a diagram showing an example of a color unevenness pattern generated when the pickled stainless steel strip was subjected to a coloring treatment without performing the method of the present invention after annealing.

Prior to a detailed description of the configuration of an apparatus for carrying out the method of the present invention, an outline of a continuous annealing pickling equipment in which the method of the present invention is carried out will be described with reference to FIG.

First, the stainless steel strip (hereinafter, simply referred to as steel strip) S unwound from the payoff reel 1 is heated by the heating furnace 2.
And undergoes heat treatment in the quenching furnace 3. At this time, a scale is formed on the surface of the steel strip S. Therefore, it is led to the next salt bath 4 (which may be subjected to other chemical pretreatment) to change the surface scale of the steel strip S, and then pickling in the pickling tank 5 consisting of a mixed acid of nitric acid and hydrofluoric acid. Descale treatment is performed with the liquid 5a. This pickling tank 5 picks up the steel strip S through semi-immersion rolls 6a and 6b.
The steel strip S has a structure of being immersed in a. Since the pickling solution 5a is attached to the surface of the steel strip S drawn from the pickling solution 5a in the pickling tank 5, the pickling solution 5a is drawn out from the pickling tank 5. Ringer roll that doubles as a roll that changes the traveling direction of the strip steel S
The adhered pickling solution 5a is squeezed by 7a and 7b, and then, if necessary, washed with a mist of only water sprayed from the water spray nozzle 11 and immersed in the washing tank 8 to sufficiently remove the pickling solution 5a. Taken up, dried in dryer 9 and wound on reel
Take up by 10.

In such a pickling process, the pickling tank 5 is used in the present invention.
The steel strip S immediately after being drawn from the pickling solution 5a in the pickling tank 5 through the semi-immersing roll 6b on the delivery side installed at a position away from the half-immersing roll 6b and the pickling solution 5a. A semi-immersion roll of mist of cleaning water and air in an amount corresponding to the amount of evaporated water of the pickling solution 5a in the pickling tank 5 from a plurality of internal mixing type two-fluid fine spray nozzles 12 installed in the nozzle header 13. Rolling oil which is sprayed onto 6b and the strip steel S to wash and remove the pickling solution 5a adhering to the strip steel S and to cool the strip steel S, which is also attached to the strip steel S and brought into the pickling tank 5. Semi-immersion rolls that have various stains such as abrasion powder during rolling and chemicals during pretreatment
The transfer to the strip steel S attached to the surface of 6b and pulled out is prevented, and the descale reaction is immediately and uniformly terminated.

Hereinafter, the relationship between such means and the method for producing a stainless steel strip for chemical coloring that does not cause a color unevenness pattern will be described.

In FIG. 1, the pickling tank 5 stores a highly-reactive pickling solution 5a composed of a mixed acid of nitric acid and hydrofluoric acid.
It is maintained at 60 ℃. Therefore, the strip steel S is drawn into the pickling solution 5a in the pickling tank 5 through the semi-immersive roll 6a on the inlet side, and at the same time, the descaling reaction is started, and the pickling is performed via the semi-immersive roll 6b on the outgoing side. The descaling process is performed until the liquid is picked up from the pickling solution 5a in the tank 5. However,
The steel strip S as it is drawn from the pickling tank 5 has sensible heat of about 50 ° C due to heat exchange with the pickling solution 5a, and its surface is highly reactive pickling. Since the liquid 5a is attached, the pickling solution 5a is simply removed by the ringer rolls 7a and 7b at a position apart from the pickling tank 5, and then the water spray nozzle 11 is used to perform conventional pickling. With the removal method,
The surface of the steel strip S is affected by its own sensible heat and the adhered pickling solution 5a, so that the surface of the strip S is not a little different from the pickling solution 5a until it leaves the pickling tank 5 and is washed by the water spray nozzle 11. Not only the reaction is continued, but also various stains such as rolling oil that adheres to the steel strip S and is brought into the pickling tank 5, abrasion powder during rolling, chemicals during pretreatment, and pickling treatment. The scale that is generated is the surface of the semi-immersion rolls 6a and 6b, especially the semi-immersion roll 6b on the exit side.
Is deposited on the surface of the steel sheet and transferred to the steel strip S. In this conventional method, the adhered pickling solution 5a squeezed by the ringer rolls 7a, 7b is moved along the strip steel S to the pickling tank 5
It flows into the inside, but at this time Ringer roll 7
Difference in rolling force between a and 7b in the longitudinal direction, ringer rolls 7a and 7b
The pickling solution adhered by the ringer rolls 7a and 7b is affected by the damage state of the roll surface of No. 5 and the shape of the steel strip S.
The amount of a varies in the width direction of the steel strip S. On the other hand, steel strip S
The water spray nozzle 11 for washing water is a ringer roll from the viewpoint of preventing the washing water from flowing into the pickling tank 5 as shown in FIG.
Although it is installed after 7a and 7b, the ringer rolls 7a and 7b are affected by the difference in the rolling force in the longitudinal direction, the damage state of the roll surface, and the shape of the strip S as described above.
If there is a difference in the drawing effect of a and 7b in the plate width direction, this cleaning water may pass through the ringer rolls 7a and 7b and flow into the pickling tank 5 along the strip steel S.

As described above, in the conventional pickling treatment step, on the surface of the steel strip S guided to the ringer rolls 7a, 7b through the semi-immersive roll 6b on the outlet side, at the time of withdrawing from the pickling tank 5 during this period. Pickling solution adhered (hereinafter sometimes referred to as adhered pickling solution), pickling solution squeezed by Ringer rolls 7a, 7b (hereinafter sometimes referred to as squeezing pickling solution),
Furthermore, the washing water (hereinafter also referred to as inflow washing water) flowing out of the ringer rolls 7a, 7b and flowing into the pickling tank 5 along the steel strip S joins together. Furthermore, if the shape of the strip steel S is also added here, these flow states of the strip steel S when the above-mentioned attached pickling solution, squeezing pickling solution, and inflowing washing water join together become quite eccentric. Things can be easily imagined. Therefore, the pickling solution adhering to the surface of the strip S has a complicated concentration and temperature distribution between the time when it is pulled out from the semi-immersion roll 6b and the ringer rolls 7a and 7b. The strip steel S and the pickling solution adhered thereto cause a non-uniform and uneven reaction.

For the reasons described above in detail, the stainless steel strip has a non-uniform surface property, but the difference in the reaction amount is so small that it cannot be visually confirmed. Therefore, in the commonly used stainless steel strip, such a reaction has been overlooked as not a problem.

However, obtaining a stainless steel strip having a uniform finish in such a microscopic aspect is succeeding to obtaining a chemically developed stainless steel strip having a good finish. Therefore, in the method of the present invention, the steel strip S is used. Immediately after the strip steel S is drawn out of the pickling tank 5 in the continuous annealing pickling step, the pickling solution 5a, which is a reaction factor, is uniformly removed, and the strip steel S is uniformly cooled to perform non-uniform descaling. Not only the reaction is suppressed, but also stains and the like adhering to the surface of the semi-immersion roll 6b on the delivery side are prevented from being transferred to the steel strip S, thereby obtaining a stainless steel strip for chemical coloring with a uniform finish. is there.

[Work]

Next, the operation of the method for producing a chemically colored stainless steel strip according to the present invention will be described.

In FIG. 2, the internal mixing type two-fluid fine spray nozzle 12 uniformly and effectively cleans the strip S drawn from the pickling solution 5a in the pickling tank 5 through the semi-immersion roll 6b on the exit side. It is the best way to serve this purpose for cooling. That is, the internal mixing type two-fluid part spray nozzle 12 has a structure in which a fine mist of air and cleaning water is obtained by atomizing pressurized cleaning water in the same nozzle by pressurized air,
By adjusting the pressure ratio between the pressure of the pressurized air and the pressure cleaning water, the particle size and spray amount of the water mist can be adjusted. As shown in FIG. 3, a plurality of the internal mixing type two-fluid fine atomizing nozzles 12 are attached to the header 13, and the strip steel S is pulled out from the pickling solution 5a in the pickling tank 5 through the semi-immersion roll 6b on the exit side. At the same time, the steel strip S is exposed to the semi-immersion roll 6b and pickling solution.
The mist of the air and the cleaning water sprayed from the two-fluid fine spray nozzle 12 is sprayed toward the position away from 5a. The spraying angle can be adjusted by the nozzle header fixing plate 14, and this is for adjusting so that the spraying part does not change even if the amount of the pickling solution 5a changes. . Further, the mist of the sprayed air and the cleaning water flows into the pickling tank 5, but if the amount of the cleaning water of this mist is too large, the concentration of the pickling solution 5a in the pickling tank 5 will increase. If the amount is too small, the cleaning / cooling effect of the steel strip S is deteriorated. Therefore, it is necessary to set the amount of water for cleaning the mist so as to have a sufficient cleaning / cooling effect and not to reduce the concentration of the pickling solution 5a in the pickling tank 5. Then, the present inventors investigated the reduction amount of the pickling solution 5a in the pickling tank 5 (the sum of the carry-out amount by the steel strip S and the evaporation amount), and found that it was about 2 / min in the apparatus of the applicant company. Yes, of these, the amount of evaporation of the pickling solution is about 0.5 / mi
Since it was n, spraying the mist cleaning water at about 0.5 / min does not significantly change the amount and the acid concentration of the pickling solution 5a in the pickling tank 5, and is sufficient to cool the steel strip S.・ Semi-immersion roll 6b on the delivery side in addition to the cleaning effect
It has been found that a sufficient cleaning effect can be obtained.

Next, the advantages of the internal mixing type two-fluid atomizing nozzle 12 suitable for achieving the method of the present invention will be described. The normal nozzle used to form water mist only by water pressure, which is generally used as a cleaning nozzle, has a narrow water pressure setting range for forming water mist, and the amount of cleaning water to obtain a uniform cleaning / cooling effect. Also, the particle size of the water mist cannot be adjusted, and the particle size of the water mist is different in the external mixing type nozzle in which the air and the cleaning water are separately supplied to the tip of the nozzle to obtain the mist of the air and the cleaning water. While it cannot be supplied in a stable state, the internal mixing type two-fluid fine spray nozzle 12 can be a means sufficient to achieve the object of the present invention. That is, as shown in FIG. 4, when supplying the two fluids of the cleaning water 15 and the pressurized air 16 to the two-fluid fine spray nozzles 12 through the respective nozzle headers 13, these pressurized air and pressurized air are pressurized. Wash water and strainer 17,1 respectively
The final purification is performed by 8, and the flow rate is adjusted by the flow rate control valves 19, 20, and the pressure and flow rate of each pressure gauge 21, 22 and flow meter 2
If it is monitored and supplied by 3, 24, the cleaning / cooling capacity can be adjusted by adjusting the mist by adjusting the flow rate ratio (pressure ratio) of the cleaning water 15 and the air 16 and each flow rate (pressure). . In order to achieve the object of the present invention, the strip steel S and the surface of the exit side semi-immersion roll 6b are immediately and uniformly cleaned without increasing the amount of the pickling solution 5a in the pickling tank 5. Since it has to be cooled, it must be an internal mixing type two-fluid fine spray nozzle 12 capable of supplying a fine mist of air and cleaning water having a high cleaning / cooling effect with a small amount of water.

A plurality of internal mixing type two-fluid fine atomizing nozzles 12 having the above characteristics are provided, and the number of nozzle headers is sufficient to process the entire width of the strip steel S to be processed and to obtain a uniform mist amount. The strip steel S is discharged from the pickling tank 5 via the semi-immersion roll 6b on the exit side, and at the same time, a plurality of the internal mixing type two-fluid fine spray nozzles 12 are arranged side by side.
Of strip water S from the group toward the position away from the semi-immersion roll 6b on the exit side and the pickling solution 5a A mist is sprayed to clean and cool the steel strip S to immediately stop the reaction between the steel strip S and the pickling solution 5a, and the semi-immersion roll 6b on the delivery side
The surface of is also washed.

〔Example〕

An example of a method for producing a stainless steel strip for chemical coloring according to the present invention will be shown below.

Example 1 In the continuous annealing pickling line shown in FIG. 1, a cleaning device for strip steel S having the configuration shown in FIGS. 2, 3 and 4 is provided on the outlet side of the pickling tank 5 to perform annealing pickling. A strip steel S that had been subjected to the treatment was manufactured. As a comparative example, a strip steel S treated by the conventional method without the above-mentioned cleaning device in the continuous annealing pickling line shown in FIG. 1 was also manufactured. The treatment based on the present invention and the treatment based on the conventional method were carried out in the same coil in order to avoid the influence between the lots of the steel strip S.

The strip steel (No. 2D finishing material specified in JIS G 4307) that has been subjected to the above treatment was colored by passing through a continuous chemical coloring line. The results and the processing conditions based on the present invention are shown in the table. As is clear from this table, in the portion where the conventional processing is performed,
Although the color unevenness pattern shown in the figure was generated, there was no color unevenness pattern in the portion subjected to the treatment according to the present invention, and it was uniformly colored.

Example 2 The strip steel S treated according to the present invention shown in Example 1 was temper-rolled to obtain a No. 2B finishing material defined in JIS G 4307, and this strip steel S was subjected to a continuous chemical coloring line. Plated and colored. The results and the processing conditions according to the present invention are also shown in the table. As is clear from this table, the color unevenness pattern shown in FIG. 5 was generated in the portion where the conventional treatment was performed, but there was no color unevenness pattern in the portion where the treatment according to the present invention was performed, and the coloration was uniform. It was

Example 3 The strip steel S treated according to the present invention shown in Example 1 is prevented by transferring shots to the surface of the strip steel S by a temper rolling mill having a roll subjected to shot projection processing. Dazzling property was imparted, and after this, continuous chemical coloring lines were passed through to color. The results and the processing conditions according to the present invention are also shown in the table. As is apparent from this table, the color unevenness pattern shown in FIG. 5 was generated in the portion where the conventional treatment was performed, but there was no color unevenness pattern in the portion where the treatment according to the present invention was performed, and the color was uniformly colored. It had been.

[Effects of the Invention] The method for producing a stainless steel strip for chemical color development according to the present invention as described in detail above has various advantages as listed below, and its industrial value is very large. There is.

(1) In a chemically colored stainless steel strip that has been reliably treated according to the method of the present invention, the occurrence of color unevenness patterns during chemical coloring can be reliably suppressed. Since the trial coloring work for confirmation of is unnecessary, the yield of these required materials can be improved. In particular, in the case of continuous chemical coloring line, this yield loss becomes large because at least the steel strip between the pay-off reel and the winding device does not become a product when the trial coloring is performed using the line. That is, in the past, this trial coloring was carried out, and if an uneven pattern was generated on the steel strip as a result, the coloring work would be stopped. Since there is a strip steel cutting device only in the vicinity, it is not possible to separate the strip steel until the tip of the strip steel reaches the take-up reel even for the separation from the strip steel that has been passed through before. At least a part of the strip steel located between the payoff reel and the winding device becomes a defective portion. For example, the strip weight is 10T and the strip width is 1,00.
When a stainless steel strip with a thickness of 0 mm and a thickness of 1.0 mm is passed through a continuous chemical coloring line with a distance of 100 m between the payoff reel and the winding device, the stainless steel strip required for trial coloring is approximately
It was 0.8 T, and this portion was often scrap in the prior art, but it became possible to commercialize this portion by carrying out the method of the present invention.

(2) The cost required to operate the continuous chemical coloring line for performing the above-described test coloring can be reduced. In other words, chemical costs, electric power, energy costs such as steam, labor costs, etc. required to manufacture a product of about 0.8T were reduced. Furthermore, since the trial coloring work is no longer required, the production capacity is improved by the amount of the trial coloring.

(3) By carrying out the method of the present invention, the carry-out of the pickling solution for the strip steel in the pickling apparatus in the continuous annealing pickling step was reduced, so that the consumption of the expensive pickling solution was reduced. Furthermore, since the cooling and washing effect of the steel strip can be sufficiently achieved by replenishing the amount of water commensurate with the evaporation of the pickling solution in the pickling apparatus, the fluctuation in the concentration of the pickling solution is small, and the stainless steel for chemical color development targeted by the present invention. Even in the production of general stainless steel strips other than strips, the practice of the present invention enables stable descaling.

(4) The stainless steel strip surface that has been treated according to the method of the present invention has high microscopic cleanliness, and has a high degree of chemical surface treatment other than chemical color treatment (electrolytic plating, electroless plating).
Even in the case of carrying out, since the surface activity of the steel strip is uniform, it is possible to obtain a uniform finished product.

(5) Since the stainless steel strip treated by the method of the present invention undergoes a great cleaning action of injecting a relatively high pressure air and a fine mist of cleaning water onto the steel strip, it is simply a water spray. Compared to the case of performing the washing by immersion in a water tank, the smut remaining on the surface of the steel strip was sufficiently removed, and therefore the appearance was uniform.

(6) When the treatment according to the method of the present invention is performed, the semi-immersion roll on the outlet side of the pickling tank is optionally cleaned with water mist. The pickling solution and dirt with high viscosity are removed, the life of the roll is extended, and this dirt is less likely to be transferred to the strip steel. Further, the number of semi-dip roll slip flaws caused by such stains was also reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of a continuous annealing pickling equipment for stainless steel strips including the method of the present invention, and FIG. 2 is a side cross section of a pickling tank for carrying out the method of the present invention in a continuous annealing pickling equipment for stainless steel strips. A schematic view, FIG. 3 is a perspective view for explaining the installation condition of the water washing device in FIG. 2, and FIG. 4 is a diagram showing the configuration of the water washing device,
FIG. 5 is a diagram showing an example of a color unevenness pattern generated when the pickled stainless steel strip was subjected to a coloring treatment without performing the method of the present invention after annealing. In the drawing S …… Strip steel 1 …… Pay-off reel 2 …… Heating furnace 3 …… Quenching furnace 4 …… Salt bath 5 …… Pickling tank 5a …… Pickling solution 6a …… Semi-immersion roll on entry side 6b …… Semi-immersion roll on the outlet side 7a …… Ringer roll (upper) 7b …… Ringer roll (lower) 8 …… Washing tank 9 …… Dryer 10 …… Winding roll 11 …… Water spray nozzle 12 …… Internal Mixing type two-body fine spray nozzle 13 …… Nozzle header 14 …… Nozzle header fixing plate 15 …… Washing water 16 …… Air 17 …… Strainer (for washing water) 18 …… Strainer (for air) 19 …… Flow control valve (for cleaning water) 20 …… Flow control valve (for air) 21 …… Pressure gauge (for cleaning water) 22 …… Pressure gauge (for air) 23 …… Flow meter (for cleaning water) 24 …… Flow meter (for air)

Claims (1)

[Claims] 1. In a mixed aqueous solution of chromic acid and sulfuric acid, which has been subjected to a heat treatment after cold rolling and a pickling treatment in a pickling solution consisting of a mixed acid of nitric acid and hydrofluoric acid, either as it is or after cold rolling. When manufacturing the stainless steel strip to be supplied to the chemical color development step by immersing the stainless steel strip immediately after being pulled out from the pickling solution in the pickling tank through the semi-immersing roll, the semi-immersing roll and the acid From a plurality of internal mixing type two-fluid fine spray nozzles installed in the nozzle header facing away from the washing liquid, washing water and air having a water amount corresponding to the amount of evaporated water of the pickling liquid in the pickling tank The method of producing a stainless steel strip for chemical color development, which comprises spraying the mist of No. 3 onto the semi-immersion roll and the stainless steel strip to stop the reaction between the stainless steel strip and the pickling solution.