KR100833031B1 - A method for manufacturing Tin plated steel sheet - Google Patents

Abstract

Provided is a method for producing a tin-plated steel sheet having excellent gloss.

According to the present invention, after spraying air at a pressure of 5 to 6 kg / cm 2 onto the surface of the tin-plated steel sheet which has exited the drag-out process in the tin-plated steel sheet manufacturing process using the drag-out process, the phenolsulfonic acid concentration is 1.5-. The present invention relates to a method for producing a tin-plated steel sheet having excellent glossiness, characterized by spraying a mixed solution of 2 g / l and a hydrochloric acid concentration of 0.3 to 0.5 g / l.

Drag-Out, Tin Plated Steel, Phenolic Sulfonic Acid

Description

A method for manufacturing Tin plated steel sheet}

1 is a schematic diagram showing equipment of a conventional Drag-Out process

2 is a schematic view showing a Drag-Out process equipment according to the present invention

   * Description of the symbols for the main parts of the drawings *

      1. Tin-plated steel sheet 2. Hold-down roll

      3. Carrier Roll 4. Ringer Roll

      5. Overflow piping 6. Pure water supply control valve

      7. Pure 8. Phenolicsulfonic acid feed pump

      9. Phenolicsulfonic acid storage tank 10. # 2 Drag-Out Tank

     11. # 2 Drag-Out Solution Supply Pump 12. # 1 Drag-Out Tank

     13. # 1 Drag-Out Solution Supply Pump 14. Spentol Sulfonic Acid

     15. Mixed solution tank 16. Hydrochloric acid

     17. Solution Spray Nozzle 18. Air Knife

     19. Compressed Air 20. Mixed Solution Supply Pump

The present invention relates to a method for producing a tin-plated steel sheet excellent in glossiness, and more particularly, by removing a non-uniform tin oxide by spraying a mixture of phenol sulfonic acid and hydrochloric acid on a tin-plated steel sheet having exited a conventional drag-out process. It relates to a tin-plated steel sheet manufacturing method that can improve the properties.

Tin oxide present on the surface of tin plated steel acts as a factor that inhibits glossiness by preventing uniform spread of molten tin during tin melting process, but it can prevent tin grain growth after melting and maintain uniform grain size It also acts as a. For this reason, the tin oxide is different in the degree of removal of tin oxide according to the work product in order to change the characteristics of the product surface according to the plating amount.

In particular, in the steel plate with a small amount of plating, the concentration of the drag-out solution is controlled to remove tin oxide relatively in order to improve surface glossiness and to prevent further oxidation.

FIG. 1 is a schematic view showing a conventional drag-out process. In general, a drag-out tank of a vertical electro tin plating process includes a tank 1 and a tank 10. Here, the first tank 12 serves to receive the plating solution buried in the steel sheet 1 after plating using pure water (7), the second tank 10 is a mixture of pure water (7) and phenol sulfonic acid The solution is used to remove tin oxide and prevent oxidation.                         

And as the Drag-Out process progresses, the tin ion concentration in tanks 1 and 2 continues to increase due to the plating solution on the steel plate, and the phenol sulfonic acid concentration in tank 2 is buried with the steel plate. It decreases continuously because of the amount and the amount used in the reaction. For this reason, in the case of the first tank 12, when the tin ion concentration becomes higher than the reference value, the entire solution is sent to the plating solution storage tank, and then pure water 7 is replenished to manage the concentration.

In addition, the second tank 10 adjusts the concentration of pure water (7) and phenol sulfonic acid through a pump (8) according to the state of the solution. In this case, a low plating amount (less than 2.8g / ㎡ plating) requires additional tin oxide removal for uniform gloss of the surface, so the phenol sulfonic acid concentration is higher than the general working concentration of 1 ~ 2 g / l 2 I work at -3 g / l. On the contrary, in order to work a high plating amount while working a low plating amount, pure water is added to the solution to dilute the solution.

However, since the conventional treatment method is performed by the concentration analysis result by wet analysis, it takes a long time to analyze and changes the concentration of the whole solution at a time. Therefore, it is difficult to uniformly manage and adjust the solution concentration. There is a problem that it is difficult to maintain the gloss. And because of these problems, it is difficult to work in parallel with a small amount of work and a lot of work, and due to the improper control of the concentration of the solution, the low plating amount in the product has become a leading cause of poor gloss defects due to non-uniform removal of tin oxide.                         

On the other hand, phenol sulfonic acid (PSA) mixed with pure water in the Drag-Out process prevents tin ions (Sn ²⁺ ) from reacting with oxygen in the atmosphere to improve the glossiness of the surface and during tin melting process. It performs the function of determining grain size of surface tin. However, this phenol sulfonic acid (PSA) plays a good role in preventing further tin oxide formation by contact with air on the surface, but lacks the ability to remove the already formed tin oxide, so this drag-out process has already produced tin. There is a limitation that the oxide cannot be removed completely.

In addition, in the case of a low plating amount of the tin plating amount of less than 2.8g / ㎡, the process of removing the tin oxide once again is required because the residual oxide on the surface is very sensitive to produce a gloss unevenness.

Therefore, the present invention is to solve the above-mentioned problems of the prior art, by spraying a phenol sulfonic acid and hydrochloric acid mixed solution through a nozzle to the tin-plated steel sheet exiting the usual Drag-Out process tin plating of 2.8 g / ㎡ or less tin plating An object of the present invention is to provide a tin-plated steel sheet manufacturing method that can improve the gloss of the steel sheet.

The present invention for achieving the above object, in the tin-plated steel sheet manufacturing process using the Drag-Out process, after spraying high-pressure air on the surface of the tin-plated steel exiting the Drag-Out process, the phenol sulfonic acid concentration is 1.5 The present invention relates to a method for producing a tin-plated steel sheet having excellent gloss, characterized by spraying a mixed solution having a concentration of ˜2 g / l and a hydrochloric acid concentration of 0.3 to 0.5 g / l.

Hereinafter, the present invention will be described.

High pressure air is applied to the surface of the tin-plated steel sheet that exits the conventional Drag-Out treatment process of the present invention by spraying a mixed solution prepared by mixing pure water and phenol sulfonic acid and hydrochloric acid to remove the tin oxide. It is characterized by preventing the glossiness non-uniformity defect of the tin-plated steel sheet of low plating amount of plating amount below 2.8g / m <2>.

That is, the present invention, as shown in Figure 1, while moving the tin-plated steel sheet through the hold down roll (2) and the carrier roll (3) to remove the plating liquid on the surface of the No. 1 Drag-Out tank, and then again The carrier roll (3) is blown with high pressure air to the surface of the steel sheet exiting the conventional drag-out process, which is passed through a conventional drag-out tank made of a mixture of pure water and phenol sulfonic acid, and then pure water and phenol sulfonic acid. It is characterized by spraying a mixed solution of and hydrochloric acid.

Therefore, as shown in one embodiment of the drag-out process equipment according to the present invention of Figure 2, the tank 15 and the pump 20 for supplying the mixed solution to the drag-out process equipment of the present invention And an air knife (Air-Knife (18)) for spraying the mixed solution on the surface of the steel sheet, and to remove the solution on the surface of the steel sheet during the drag-out process by blowing compressed air. It is provided.                     

That is, in the present invention, in order to remove the solution buried on the surface of the steel sheet exiting the existing Drag-Out process, the air-Knife (18) is laid at the rear end of the existing Drag-Out process, and the compressed air 19 is sprayed do.

At this time, it is preferable to manage the air pressure in the range of 5 to 6 kg / ㎠, and if the air pressure is too low, the effect of improving the glossiness is reduced by mixing with the mixed solution due to the decrease in the degree of removal of the solution buried in the tin-plated steel sheet. On the other hand, too high can cause an increase in plate vibration and noise.

After spraying the high pressure air through the air knife as described above, the mixed solution of pure water, phenol sulfonic acid and hydrochloric acid is sprayed on the surface of the plated steel sheet.

In the present invention, the concentration of phenolsulfonic acid in the mixed solution sprayed on the surface of the steel sheet is limited to 1.5 to 2 g / l. If the concentration of phenol sulfonic acid is less than 1.5 g / l, the bonding ratio of tin and phenolsulfonic acid on the surface is lowered, so that the oxidation of tin on the surface may occur in a later process, which may cause unevenness of surface gloss. If it exceeds, excessive phenol sulfonic acid remains on the surface of steel sheet, so it is not completely removed in the post process. Therefore, harmful phenol sulfonic acid remains on the surface of the product. Therefore, the amount of chromium hydroxide adhered in the Chromate process This is because it inhibits.

In addition, the hydrochloric acid in the mixed solution acts as a factor to reduce the adhesion of chromium hydroxide in the Chromate process, which is a post-treatment process of tin-plated steel sheet, and in addition to tin oxide as well as tin oxide Appropriate concentration control is necessary because it also removes pure tin from the oxide underlayer.

In the present invention, the concentration of such hydrochloric acid is limited to 0.3 to 0.5 g / l, but if the concentration is less than 0.3 g / l, the effect of addition cannot be expected, and if it exceeds 0.5 g / l, Cl-ion (chloride) This is because a large amount of tin remains on the surface of the tin-plated steel sheet, which reduces the adhesion amount of chromium hydroxide in the subsequent Chromate process and decreases the glossiness of the surface by local excess removal of the tin oxide and tin layer.

In the present invention, it is preferable to spray the mixed solution having the above composition to the surface of the steel sheet at an injection amount of 90 to 110 l / hr. If the spraying amount is less than 90ℓ / hr, tin oxide on the surface of tin plated steel is not sufficiently removed.If it exceeds 110ℓ / hr, it flows from the surface of tin-plated steel sheet, which is a sprayed solution, causing uneven luster of the surface Because you can.

As described above, the present invention sprays a mixed solution of phenol sulfonic acid and hydrochloric acid on the surface of the tin plated steel sheet to remove tin oxide remaining on the surface, and further prevents oxidation of tin, thereby preventing tin plating amount of 2.8 g / m 2 or less. It can effectively prevent gloss non-uniformity defects caused by tin plated steel sheet of low plating amount.

Hereinafter, the present invention will be described in detail through examples.                     

(Example 1)

The tin-plated steel sheet was dragged out using a conventional Drag-Out process facility, and then the surface was sprayed with high pressure air of 5 kg / cm 2. Thereafter, as shown in Table 1, a mixed solution of phenol sulfonic acid and hydrochloric acid having different compositions was sprayed onto the surface of the steel sheet, and the spraying amount of the mixed solution was controlled to 90 l / hr. In addition, the distance between the mixed solution injection nozzle and the steel sheet was set to 10cm, the nozzle was placed at intervals of 10 cm in the width direction for a steel sheet having a width of 1000mm. The speed of the steel sheet was 200 m / min.

As described above, the degree of glossiness of the surface of the tin-plated steel sheet sprayed with the mixed solution was evaluated, and the degree of gloss according to the concentration of each component of the mixed solution for the sample amount of 1.1 g / m2 was graded from 1 to 5 in excellent order. It is shown separately.

division Phenolic sulfonic acid concentration (g / l) Hydrochloric Acid Concentration (g / ℓ) Glossiness (Rating) Inventive Example 1.5 to 2.0 0.3 to 0.5 One Comparative Example 1 0.5 to 1.0 - 4 Comparative Example 2 0.5 to 1.0 0.3 to 0.5 3 Comparative Example 3 0.5 to 1.0 0.5 to 0.8 3 Comparative Example 4 1.0 to 1.5 - 3 Comparative Example 5 1.0 to 1.5 0.3 to 0.5 2 Comparative Example 6 1.0 to 1.5 0.5 to 0.8 3 Comparative Example 7 1.5 to 2.0 - 2 Comparative Example 8 1.5 to 2.0 0.5 to 0.8 2 Comparative Example 9 2.0 to 2.5 - 3 Comparative Example 10 2.0 to 2.5 0.3 to 0.5 2 Comparative Example 11 2.0 to 2.5 0.5 to 0.8 3

As shown in Table 1, it can be seen that in the case of the present invention in which the mixed solution composition is properly controlled, the gloss is excellent as 1.

On the other hand, Comparative Examples (1 to 3) having a lower phenol sulfonic acid concentration than the present invention had a low bonding ratio between tin and phenolsulfonic acid on the surface of the steel sheet, so that oxidation of the surface tin occurred in a later step, resulting in poor surface glossiness. .

In addition, Comparative Examples (9 to 11) having a higher phenol sulfonic acid concentration than the present invention had poor surface glossiness, and excessive phenol sulfonic acid remained harmful to the human body on the surface of the steel sheet. In addition, the comparative examples (4-8) in which the phenol sulfonic acid concentration is in the range of the present invention but the concentration of hydrochloric acid are outside the range of the present invention also generally have poor glossiness on the surface of the plated steel sheet.

(Example 2)

In order to examine the effect of the mixed solution injection amount of phenol sulfonic acid and hydrochloric acid sprayed on the surface of the tin-plated steel sheet and the air pressure in the air knife, the experiment was performed by varying its operating conditions as shown in Table 2. At this time, the composition of the mixed solution was used as the composition of the invention example shown in Example 1, other operating conditions, glossiness evaluation criteria and the like are the same as in Example 1.

division Solution injection amount (ℓ / Hr) Air Knife Pressure (kg / ㎠) Glossiness (Rating) Inventive Example 90-100 5 to 6 One Comparative Example 1 60-70 3 to 4 2 Comparative Example 2 60-70 5 to 6 2 Comparative Example 3 60-70 7-8 2 Comparative Example 4 70-80 3 to 4 2 Comparative Example 5 70-80 5 to 6 2 Comparative Example 6 70-80 7-8 2 Comparative Example 7 90-100 3 to 4 2 Comparative Example 8 90-100 7-8 One Comparative Example 9 100-110 3 to 4 2 Comparative Example 10 100-110 5 to 6 One Comparative Example 11 100-110 7-8 One Comparative Example 12 110 to 120 3 to 4 2 Comparative Example 13 110 to 120 5 to 6 2 Comparative Example 14 110 to 120 7-8 2

As shown in Table 2, the example of the present invention in which the injection amount and air pressure of the mixed solution were properly controlled was excellent in its glossiness.

However, Comparative Examples (1 to 6) in which the injection volume of the mixed solution was less than 90 l / hr did not sufficiently remove tin oxide on the surface of the tin-plated steel sheet, resulting in poor glossiness, and comparative examples exceeding 110 L / hr (9 to 6). 14) shows that the glossiness is not constant since the sprayed mixed solution may flow down from the tin-plated steel sheet to generate non-uniform surface gloss.

In addition, Comparative Example (7) having a lower air pressure than the range of the present invention did not have good glossiness, while High Comparative Example (8) had good glossiness, but it was not preferable because of the occurrence of shaking of the plated steel sheet.

 As described above, the present invention, by spraying a phenol sulfonic acid and hydrochloric acid mixed solution through a nozzle to the tin-plated steel sheet exiting the conventional Drag-Out process, it is possible to improve the gloss of tin-plated steel sheet with a tin plating amount of 2.8 g / ㎡ or less It can be effectively produced tin-plated steel sheet.

Claims (3)

In the tin-plated steel sheet manufacturing process using the drag-out process, After spraying air at a pressure of 5 to 6 kg / cm 2 onto the tin-plated steel sheet leaving the Drag-Out process, a mixed solution having a phenol sulfonic acid concentration of 1.5 to 2 g / l and a hydrochloric acid concentration of 0.3 to 0.5 g / l Excellent tin-plated steel sheet manufacturing method characterized by spraying. The method of claim 1, wherein the mixed solution is sprayed at an injection amount of 90 to 110 l / hr. delete

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