KR100470639B1 - A method for manufacturing heavily coated tin plate for k-plate application with no formation of smudge - Google Patents

Abstract

The present invention relates to a method for producing a post-plated stone plate, also known as K-plate used as a material of a can containing a juice drink, the object of the present invention comprises electro tin plating, reflow treatment, chemical treatment, etc. In the manufacturing method of the stone plate, by optimizing the manufacturing conditions of each step, to provide a method for producing a white-plated after-plated stone plate using less existing splatter without using additional treatment or equipment There is.

In order to achieve the above object, the present invention provides electro tin plating on the stone master disc, and then performs a chemical treatment after performing a reflow treatment consisting of a drag-out treatment using a drag-out solution, a heating treatment, and a quenching treatment. In the method of manufacturing a stone-plated steel sheet comprising a, the temperature of the plating liquid during the electro-tin plating is 45 ~ 55 ℃, the concentration of ENSA mixed in the drag-out solution during the drag-out treatment of the reflow treatment is 0.5 g / Less than l, and the amount of chromium deposited in the film formed by the above chemical treatment is 3 ~ 5 mg / ㎡ The method for producing a white-plated after-plated low-grade galvanized steel sheet, characterized in that the technical gist.

Description

A method for manufacturing white-plated post-plated stone plate for less whiteness {A METHOD FOR MANUFACTURING HEAVILY COATED TIN PLATE FOR K-PLATE APPLICATION WITH NO FORMATION OF SMUDGE}

The present invention relates to a method for producing a post-plated stone plate, also known as K-plate used as a material of a can containing a juice drink, more specifically, the stone plate by electroplating, reflow treatment, chemical treatment When manufacturing in accordance with the present invention, by optimizing the respective manufacturing conditions, to prevent the occurrence of smudge (sudge) on the surface relates to a method for producing a white plate post-plated stone plate.

Generally, after the electroplating of tin plate with acidic plating solution, the plating layer is melted and solidified by reflow treatment to give glossiness of the plating layer, and then chemical treatment using sodium dichromate is performed thereon. Finally, it is prepared by applying antirust oil. The reflow treatment is composed of three stages: a drag-out treatment, a flux treatment step for preventing oxidation of the plating layer surface, a heat treatment for melting the plating layer, and a quenching treatment for rapidly solidifying the molten plating layer.

On the other hand, the post-plated stone plate is used as the material for the white pipe to be plated adhesion amount of 8.4 ~ 11.2g / ㎡ per one side, in contact with the contents immediately without applying lacquer inside the can in the manufacturing process. At this time, since the contents of the cans are mostly acidic juice drinks, the tin plating layer must completely cover the steel sheet to prevent corrosion of the cans. In addition, since the plating layer is exposed as it is, the appearance such as surface glossiness should be excellent, and in particular, a compound mainly composed of tin oxide in the form of powder called sage should be avoided.

If smudges are generated on the surface of the steel sheets, problems such as contamination of the conveyor belt in the shearing process, defects such as roll marks on the surface, contamination of the pipe making tool, and mixing of black powder into the can occur. Done. However, it is only known that tin powder or tin oxide react after chemical treatment in the form of gray spot or black spot after the plating, and the exact cause of the spot is not known. It is a state.

As a well-known technique for reducing the occurrence of splatter in post-plated stone plate, a method of performing anodic electrolytic treatment in alkaline solution before chemical treatment after reflow disclosed in Japanese Patent Laid-Open No. 5-88193, Japanese Patent Laid-Open No. 61-104099 Cathodic electrolytic treatment in aqueous sodium bicarbonate solution prior to the chemical treatment disclosed in U.S. Patent No. 52, immersed in epoxidized soybean oil after chemical treatment in Japanese Patent Application Laid-Open No. 52-91747, and electroplated in Japanese Patent Application No. 51-92739. A method of further performing zinc plating and a method of adding an organic compound to a chemical treatment solution of South African Patent No. 70-08647 are known. However, the above known technologies commonly require a facility for carrying out a separate electrolytic treatment or oiling treatment, and also provide an application problem such as additionally performing zinc plating which may degrade the intrinsic properties of the tin plating layer. Holding it.

The inventors have conducted a detailed analysis of the components of the swabs to find out the constituents and to investigate the influence of process variables on the generation of swabs in order to find out how to minimize the spots occurring on the plated stone plate. And the present invention has been completed, and an object of the present invention is to provide a method for producing a fine-grained steel sheet including electro tin plating, reflow treatment, chemical treatment, and the like, by optimizing the manufacturing conditions of each step, The present invention provides a method for manufacturing white-plated white plated stone plate using less existing scoop without using additional facilities or equipment.

The present invention for achieving the above object,

In the method of manufacturing a stone plate steel comprising electroplating the stone plate, performing a reflow treatment consisting of a drag-out treatment using a drag-out solution, a heat treatment, and a quenching treatment, followed by a chemical treatment ,

The temperature of the plating solution during the electro tin plating is 45 ~ 55 ℃,

In the drag-out process of the reflow process, the concentration of ENSA incorporated in the drag-out solution is 0.5 g / l or less, and

The amount of chromium deposited in the coating formed by the chemical treatment is 3 to 5 mg / m 2, and relates to a method for producing a white-plated low-plated white-plated steel plate.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The inventors of the present invention analyze the scotch component, and the gray scotch is composed of tin powder and SnO, and in addition to Sn, Fe, which is a black scouring layer, SnOx (x = 1-2) and an amorphous chromium compound We found out that it was comprised. In addition, the present inventors have estimated the relevant factors from the electroplating stage and investigated their influences in order to identify the root cause of the splatter occurrence. As a result, the splattered, tin-plated layer is oxidized in the reflow process to form a tin oxide layer. It was found that the layer was formed by reaction with a chemical treatment solution. In more detail, it is as follows.

First, in the electro tin plating step, when a poor adhesion layer is formed by an inappropriate plating solution and plating conditions, the surface area is increased to promote oxidation of the plating layer,

Secondly, if the treatment conditions are inappropriate during the reflow process, the plating layer oxidation can be promoted.

Third, tin oxide layer reacts by chemical treatment conditions.

Based on the above cause analysis results, the inventors of the present invention, based on the three basic causes of the above, conditions for forming a dense plating layer during electro tin plating, conditions that can inhibit oxidation during reflow, tin oxide layer during chemical treatment As a result of examining the conditions for minimizing the reaction, the temperature of the plating solution was maintained at 45-55 ° C during electro tin plating, and the concentration of ENSA mixed in the solution was 0.5g during the drag-out of reflow treatment. / l or less, and found that it is desirable to manage the amount of chromium deposition in the film formed by chemical treatment in the range of 3 to 5 mg / m 2.

Hereinafter, the manufacturing conditions of this invention are demonstrated.

First, as described above, in the present invention, when electro tin plating is performed on the stone master disc, it is preferable to maintain the temperature of the plating liquid at 45-55 ° C., for the following reasons. The electroplated layer grows crystallographically from the Sn (002) plane to the <100> direction. When the plating solution temperature is low, the nucleation is insufficient and the (002) plane is formed in a direction parallel to the surface, so that the neighboring crystal nuclei are formed. Since they grow only in the vertical direction without interfering with each other, a dense plating layer is formed. In addition, as the plating solution temperature increases, the nucleation becomes active and the (002) plane is formed in a direction slightly inclined from the surface of the specimen, so that the growing crystal nuclei interfere with each other and prevent growth in the same direction, so that the crystal orientation is disordered and the shape is Dense crystals are formed. In order to acquire such an effect, it is preferable to manage the temperature of a plating liquid to 45 degreeC or more which is a temperature higher than the conventional 30-40 degreeC. However, the higher the plating liquid temperature, the more evaporation of the plating liquid becomes and the oxidation of tin ions is promoted, so the upper limit of the applicable plating liquid temperature is preferably set to 55 ° C. 1 (a) and (b) are photographs obtained by observing the crystal shape of the tin plating layer according to the plating liquid temperature with an electron microscope, and FIG. 1 (a) is a case where the temperature of the plating liquid is 30 ° C., and FIG. 1 (b) ) Is the case where the temperature of the plating liquid is 50 ° C. As shown in Figs. 1 (a) and (b), in the case of Fig. 1 (a) where the temperature of the plating liquid is 30 ° C., a dense plating layer is formed. It can be seen from FIG. 1 (b) that the temperature of the plating liquid is 50 ° C. that a dense plating layer is formed.

Next, in the drag-out process of the reflow process, as described above, it is preferable to manage the concentration of ENSA mixed in the drag-out solution to 0.5 g / l or less. The drag-out treatment is for flux-treating the surface of the plating layer, and uses a thin plating solution without adding ENSA, and is an additive in the plating solution by a plating solution buried in a steel strip and mixed into a drag-out solution by a continuous operation. The concentration will increase gradually. Among the components of the plating solution, PSA performs a flux function as a strong acid, but ENSA is a component that can easily form a sludge. When using a drag-out solution having a high ENSA concentration, the ENSA component precipitates on the surface of the plating layer during reflow heating. This not only becomes a part of the spotted component later, but also promotes oxidation of the plating layer. Therefore, in order to prevent the occurrence of splatter, it is necessary to manage the content within the range that the ENSA may not be precipitated during the heating process, the inventors experimented by heating if the ENSA concentration in the drag-out solution is 0.5 g / L or less I found out that no poems were deposited. Therefore, the concentration of ENSA in the drag-out solution is preferably limited to 0.5 g / l or less. The ENSA stands for ethoxylated α-Naphthol sulfonic acid.

Finally, in the coating formed by the chemical treatment, the amount of chromium deposition is preferably in the range of 3 to 5 mg / m 2. The smudge is formed by the reaction of the tin oxide on the surface of the plating layer with the chemical treatment solution, but if the amount of chromium deposition is 5 mg / m 2 or more, an excessive reaction occurs, which is not preferable. However, if the amount of chromium deposition is too small, the anti-oxidation effect of the plating layer, which is a natural function of the chemical treatment, is lost. Therefore, the lower limit is preferably set to 3 mg / m 2.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

As the base steel sheet, electrolytic degreasing under ordinary conditions using a plating apparatus having a process of electrolytic degreasing, rinsing, pickling, rinsing, electroplating, and rinsing with respect to a low carbon stone master plate having a thickness of 0.22 mm manufactured by a conventional method Pickled. Electroplating was performed in the state which simulates the situation which a steel strip moves in an actual manufacturing process by circulating a plating liquid. At this time, an acidic plating solution composed of ordinary tin sulfate, PSA, and ENSA was used as the plating solution, and the plating solution was electroplated in an amount of 11.2 g / m 2 per single side while changing the temperature of the plating solution as shown in Table 1 below.

The electroplated specimen was fluxed with a drag-out solution with varying ENSA concentrations as shown in Table 1 below, and then heated to a maximum temperature of 260 ° C. at the center of the specimen using a resistance heating reflow apparatus. It was quenched in water at 캜.

The reflowed specimens were chemically treated by adjusting the amount of chromium deposition as shown in Table 1 by varying the amount of charge in a chemical treatment solution (aqueous sodium bichromate solution) for a conventional electroplated steel sheet in a beaker electrolyzer. At this time, the chromium adhesion amount was measured by the electrolytic peeling method which is a normal measuring method.

Then, to quantify the occurrence of smudges, an apparatus for measuring the one-sided friction coefficient was used. The arrangement consists of placing the specimen on the specimen stage and pulling the specimen at a speed of 1m per minute in the vertical direction of the load direction while pressing at a load of 30kgf with a die of 40mm x 50mm. At this time, if the filter paper is inserted between the specimen and the die, the filter paper will be smudged out, and the amount of smudge will be removed from the 1st grade (nearly burried) to the 5th grade (black stained) by visual discrimination. The incidence of swamps was quantified by stepwise. If the snuff outbreak rating is 2 or less, there is no problem in use.

division Manufacture conditions Evaluation results Plating solution temperature (℃) ENSA concentration in drag-out solution (g / l) Chemical treated chromium adhesion amount (mg / m ² ) Outbreak Grade Inventive Example 1 45 0.35 4.26 2 Inventive Example 2 50 0.35 4.38 One Inventive Example 3 54 0.35 4.29 One Inventive Example 4 47 0.03 4.78 2 Inventive Example 5 47 0.28 4.41 One Inventive Example 6 47 0.46 3.94 2 Inventive Example 7 53 0.35 3.22 One Inventive Example 8 53 0.35 3.59 One Inventive Example 9 53 0.35 4.87 2 Inventive Example 10 47 0.46 3.85 One Inventive Example 11 47 0.46 4.05 One Inventive Example 12 47 0.46 4.66 2 Comparative Example 1 35 0.35 4.27 4 Comparative Example 2 60 0.35 4.55 2 Comparative Example 3 45 0.7 4.03 4 Comparative Example 4 45 0.95 3.89 5 Comparative Example 5 45 0.35 2.38 One Comparative Example 6 45 0.35 6.23 4 Comparative Example 7 45 0.35 9.08 5

As shown in Table 1 above, in the case of Inventive Examples (1) to (12) manufactured according to the production conditions of the present invention, it can be seen that the snot grade is 1 to 2, which is very good.

However, Comparative Example (1) having a lower temperature of the plating liquid than the invention condition had a poor grade, and Comparative Example (2) having a high plating solution temperature of 55 ° C. had almost no occurrence of squeak, but it was applied due to severe evaporation of the plating liquid. There was a phase problem. In Comparative Examples (6) and (7) having a chemically treated chromium adhesion amount of 5 mg / m 2 or more, oxidation of the plating layer was severe, and Comparative Example (5) having a concentration of 3 mg / m 2 or less had a problem of oxidizing to yellow color during storage. It was not applicable. In addition, the comparative examples (3) and (4) having an ENSA concentration of 0.5 g / L or more during drag-out had a problem of severe occurrence of sessage due to precipitation of ENSA on the surface.

As described above, according to the present invention, a dense plated layer is formed during electroplating, oxidation is suppressed in the reflow process, and excessive reaction between tin oxide and the chemical treatment solution on the surface of the tin plated layer is suppressed, so that there is little occurrence of splatter. It is effective to produce a white plate post-plated stone plate.

1 (a) and (b) are photographs (by scanning electron microscope (5000 times magnification)) showing the crystal shape of the electro-tin plating layer according to the plating liquid temperature,

(a) is when the plating liquid temperature is 30 ℃

(b) shows the case where the plating liquid temperature is 50 ° C.

Claims (1)

In the method of manufacturing a stone plate steel comprising electroplating the stone plate, performing a reflow treatment consisting of a drag-out treatment using a drag-out solution, a heat treatment, and a quenching treatment, followed by a chemical treatment , The temperature of the plating solution during the electro tin plating is 45 ~ 55 ℃, In the drag-out process of the reflow process, the concentration of ENSA incorporated in the drag-out solution is 0.5 g / l or less, and Method for producing a white-plated after-plated stone plate for less whiteness, characterized in that the coating amount of chromium in the film formed by the chemical treatment is 3 ~ 5 mg / ㎡