JPH03221220A - Manufacture of drawn and squeezed can - Google Patents

Abstract

PURPOSE:To obtain a steel can excellent in color tone of outer surface by forming a zinc electroplating layer of the specific amount and a tin electroplating layer of the specific amount at its upper layer on the steel sheet surface from the surface side of steel sheet, executing drawing and squeezing so as to make the plated surface to the outer surface, and then executing substituting plating of the tin. CONSTITUTION:In order to reduce an exposure of steel generated with the drawing-squeezing work (DI-work), by utilizing the two layers plated steel sheet of tin/zinc, the DI-working is executed so as to make the plating surface of the outer surface of the can, and then it is coated by substituting plating of the tin. The surface treated steel sheet formed with the zinc electroplating layer of 0.5-10.0g/m<2> and the tin electroplating of 1.0-5.6 g/m<2> at its upper layer from the surface side of steel sheet on the one side, at least, of the surfaces of steel sheet, is subjected to squeezing so as to make the tin/zinc plated surface to the outer surface of the can and the DI-can is obtained. After washing this DI-can, it is immersed in the tin plating bath, subjected to substituting plating of the tin. Therefore, the steel DI-can of the color tone of outer appearance equal to the aluminium DI-can can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a drawn and ironed can using a steel plate.

(Prior Art) Generally, squeezed cans (hereinafter abbreviated as DI cans) are used as containers for beer, carbonated drinks, and the like.

Conventionally, in the production of DI cans using steel plates, the surface has a
A surface-treated steel sheet electroplated with 5.6 g/m of tin is used. That is, in order to ensure workability in the drawing and ironing process, the above-mentioned surface-treated steel sheet is used in which the tin plating layer is lubricated.

(Problem to be solved by the invention) A DI can using the above-mentioned surface-treated steel plate (hereinafter referred to as a conventional steel DI can) is a DI can using an aluminum plate (
The outer color tone is poor compared to aluminum DI cans (hereinafter abbreviated as aluminum DI cans).
That is, conventional steel DI cans have a blackish color tone and have a problem of poor print finish, especially white print finish.

The present invention provides a surface treatment method for the above-mentioned surface-treated steel sheet and a DI
By improving the surface treatment method of DI cans after processing,
A method for manufacturing steel DI cans that can produce steel DI cans with significantly superior external color tone than conventional steel DI cans, steel DI cans with an external color tone comparable to that of aluminum DI cans, or steel DI cans with an external color tone level that exceeds that of aluminum DI cans. It provides:

(Means for Solving the Problems) The present invention first electrogalvanizes at least one side of the surface of a steel sheet with a zinc amount of 0.5 to lo, Qg/rn', and then electroplats the upper layer of the galvanized layer. A surface-treated steel sheet is obtained by tin-plating 1.0 to 5.6 g/rn', and this surface-treated steel sheet is drawn and ironed so that the tin/zinc-plated surface becomes the outer surface of the can to produce a drawn and ironed can. The method for producing a drawn and ironed can is characterized in that after washing the drawn and ironed can, the drawn and ironed can is immersed in a tin plating bath to perform tin displacement plating.

The present invention employs the following technique as a means for improving the external color tone of steel DI cans.

(1) As a surface-treated steel sheet, tin with an electrogalvanized layer of 0.5 to 10.0 g/m and an electrolytic tin plating layer of 1.0 to 5.6 g/rn' formed on at least one side of the steel sheet from the surface side of the steel sheet. /Use double-layer zinc plated steel sheet.

(2) Perform drawing and ironing (DI processing) so that the tin/galvanized surface of this surface-treated steel sheet becomes the outer surface of the can.

f3) As a DI can surface treatment method after DI processing, tin electroless plating (displacement plating) is performed.

The disadvantage of DI cans using steel plates is the external color tone or aluminum D.
The reason why they are inferior to I cans is that after DI processing, the tin coating is not sufficient and the iron surface of the base material is exposed. In the present invention, in order to reduce the iron exposure caused by this DI processing, the above-mentioned tin/zinc double-layer plated steel sheet is used as the surface-treated steel sheet, and then the tin/zinc-plated surface of the above steel sheet becomes the outer surface of the can. , the slight defect (exposed iron) remaining after DI processing is covered with tin displacement plating.

By employing the three technologies described above, the present invention achieves a steel DI can with significantly superior outer color tone than conventional steel DI cans, an outer color tone level comparable to that of aluminum DI cans, or an outer color tone level exceeding that of aluminum DI cans. It is possible to obtain a steel DI can.

(Function) The content of the present invention will be explained in more detail below along with the function.

First, the treatment method for the surface-treated steel sheet used and the meaning of using the surface-treated steel sheet will be explained.

As mentioned above, electro-tinned steel plates are used in steel DI cans to improve DI workability. A feature of the present invention is that a zinc plating layer is provided below the tin plating layer within a range that does not impair DI processability.

The upper limit of the thickness of this galvanized layer may be within the range that does not impair DI formability as described above.

According to the investigation results of the present inventor, under normal DI processing conditions, if the tin plating amount of the upper layer is 1.0 to 5.6 g/m, even if the zinc plating amount of the lower layer is 10 g/m or less. BADI
Processability is within a practical range, and one can can be manufactured if the processability is good.

Next, the lower limit of the amount of zinc plating will be described. The purpose of the present invention is to improve the external color tone of DI cans manufactured from steel sheets, and to improve the color tone of the outer surface of DI cans manufactured from steel sheets.
If the amount of zinc plating is less than 0.5 g/m, there will be a lot of iron exposed like in normal tin-plated steel sheets, and even if you perform subsequent tin displacement plating, it will be difficult to cover the exposed iron parts with tin. It is. Therefore, zinc plating of 0.5 g/m or more is required.

In addition, within the above upper and lower limit ranges, the larger the amount of base zinc plating, the greater the improvement in the external color tone.From the viewpoint of manufacturing cost, the base zinc plating should be adjusted to the required level according to the required level of external color tone within the above upper and lower limit ranges. It is preferable to plate the minimum amount that satisfies the requirements.

Next, a method for improving the tin coverage on the outer surface of the can and reducing the exposed portion of the iron base by electroless plating tin in the surface treatment process of the DI can after DI processing will be described.

In the present invention, the exposed iron parts generated during DI processing are subjected to displacement plating with tin by immersing the zinc exposed on the outer surface of the can in a tin plating bath, thereby coating the exposed iron parts with tin. be. Therefore, the zinc plating layer placed under the tin plating has the effect of reducing iron exposure during DI processing, and the effect of making tin plating easier by replacing it with tin during the subsequent tin plating. It has two roles.

Usually, DI cans processed using electro-tinned steel plates or aluminum plates are washed with a washing solution to remove dirt (lubrication holes, etc.) during DI processing. Next, a chemical conversion treatment bath (phosphate bath, zirconate bath, etc.) is applied to improve paintability and rust resistance.
It is chemically treated inside.

The steps for carrying out the displacement tin plating of the present invention include: (1) Performing displacement tin plating in place of the above chemical conversion treatment; (2) Providing a new treatment step before the above chemical conversion treatment and after the cleaning step to perform displacement tin plating. , followed by chemical conversion treatment, etc., but the present invention is not particularly limited to this.
A tin plating process may be provided depending on the equipment configuration. According to the present invention, cleaning is performed according to the steps after the can female molding after the Dllffl molding.

After that, displacement tin plating may be performed in a pan plating bath, and coating printing may be carried out immediately, or coating printing may be carried out after chemical conversion treatment. However, it is not preferable to provide a new processing step in terms of manufacturing costs, and it is preferable to adopt the method (2) above and perform displacement tin plating and immediately paint and print.

Next, the tin plating bath referred to in the present invention will be explained.

In the present invention, since the steel sheet is galvanized to facilitate the electroless plating of tin, a special electroless tin plating bath is used as the tin plating bath (normal electroless plating baths contain a reducing agent, There is no need to use a reducing agent to reduce and precipitate tin. Instead, the zinc is dissolved on the surface of the steel sheet, especially where the surface tin plating layer has deteriorated, and the zinc is dissolved where iron is exposed. is reduced and precipitated as metal. That is, when zinc is dissolved, tin is displacement plated. Therefore, as the tin plating bath, a tin sulfate bath, a ferrostane bath (phenol sulfonic acid bath), a phosphoric acid bath, etc., which are generally used in electro-tin plating, can be used. Other alkaline tin plating baths are also available.

(Example) Hereinafter, description will be made according to examples.

Ordinary low carbon cold rolled steel plate (plate thickness 0) used for DI can manufacturing
．． 28 mm), degrease both sides with an electric tin plate under the following conditions, pickle, then zinc plate one side, then tin plate both sides. Thereafter, both sides were subjected to chromate treatment to produce a steel plate for DI cans.

As a comparison material, an ordinary electrolytic tin-plated steel sheet for DI cans was used, which was only tin-plated and not zinc-plated.

[Degreasing, pickling, electroplating, chromate treatment conditions] (1
) Degreasing NaO830g/1 Bath temperature 60°CI
OA/dtn'1 second Cathode electrolytic degreasing (2) Acid washing H2S0450g/1 Bath temperature 30
°CIOA/di1 second Cathode electrolytic pickling f3) Zn plating ZnSO4150g/l H2
SO, 10g/A' Bath temperature 50°C2OA/drn'
Cathode electrolytic treatment (4) Sn plating 5nSO, 60g, /n PSA
(phenol sulfonic acid) 50g# Bath temperature 50℃ 2OA/dm Cathode electrolytic treatment (5) Chromate treatment Na2Cr20t 30g,
/ 1 Immersion treatment for 2 seconds in a bath with a bath temperature of 40° CPH 1.5 Next, this steel plate was subjected to DI processing under normal conditions so that the Sn/Zn plated surface became the outer surface of the can (the plate after DI processing The thickness was set to 0.100 mm). After that, this DI
After degreasing the can with an alkaline degreasing solution, Sn
Replacement plating was performed.

[Sn displacement plating conditions] (1) Bath composition 5nSO, 60g/A PS, A (phenolsulfonic acid) 50g # (2) Bath temperature 40-600c (3) Immersion time (plating time) 20 seconds Manufactured in this way The whiteness of the outer surface of the can body of the DI can was investigated by printing with white ink (coating amount: 50 mg/dm).

Table 1 shows the amount of zinc plating, tin plating, displacement tin plating, and after DI processing and displacement tin plating of the sample materials.

The whiteness (L value) of the outer surface of the can body after printing is shown.

Table 1 also shows Comparative Example 6, in which the outer surface of the can body of an aluminum DI can using an aluminum plate was printed with white ink (coating amount: 50 cm,
/dm) The whiteness (L value) of the outer surface of the can body after washing is also shown.

The whiteness (L value) is measured using an automatic colorimeter (Suga Test Instruments).
Using the scoop Al1-CH-1) Te JrS Z8701
i, 1 m group was measured.

Electrotin plating Ml in Table 1, 2g/rd, 1.5g/
rn”, 2.0g/m, 2.8g%, 5
．． 6g, /rn' Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, Examples 4 to 6 and Comparative Example 4
, Comparing Examples 7 and 8 and Comparative Example 5, it is found that tin displacement plating is performed only by applying electrogalvanizing of 0.5 g/m or more to the surface of the steel sheet, and no electrogalvanizing is applied to the lower layer. It can be seen that the external color tone is significantly improved compared to each comparative example.

Also, referring to Comparative Example 6, when the upper layer electrolytic tin plating amount is 1.5 to 2.8 g7'm' than Examples 2 to 6, 1.5 to 2.8 g7'm' is applied to the lower layer. It can also be seen that by applying og/rn' electrogalvanizing and performing DI processing copper-tin displacement plating, the external color tone can be improved to the same level as that of aluminum DI cans.

Furthermore, from Examples 7 and 8, the amount of electrolytic tin plating on the upper layer was 5.6 g.
/m, it can be seen that by electrolytically galvanizing the lower layer at 1.0 g/m and performing DI processing copper-tin displacement plating, it is possible to improve the external color tone to a level exceeding that of aluminum DI cans.

(Effects of the Invention) As detailed above, according to the method of the present invention, the outer color tone is significantly superior to that of conventional steel DI cans, and furthermore, aluminum D.I.
It is possible to obtain a steel DI can with an external color tone level comparable to that of an I can or an excellent external color tone level exceeding that of an aluminum DI can.

Claims (1)

[Claims] First, the amount of zinc is 0.5 on at least one side of the steel plate surface.
~10.0g/m^2 electrolytic galvanizing is performed, and then the top layer of the zinc plating is electroplated with a thickness of 1.0~5.
A surface-treated steel sheet was obtained by plating with 6 g/m^2 of tin, and this surface-treated steel sheet was drawn and ironed so that the tin/zinc-plated surface became the outer surface of the can to obtain a drawn and ironed can.
A method for manufacturing a drawn and ironed can, which comprises washing the drawn and ironed can and then immersing it in a tin plating bath to perform tin displacement plating.