JPS5825493A - Shear spun can and its production - Google Patents

Abstract

PURPOSE:To produce a shear spun can having excellent paint adhesiveness and corrosion resistance with a small quantity of tin plating by subjecting a tin-plated steel plate which is plated with tin at a fairly small quantity and has surface roughness in a constant range to drawing and shear-spinning. CONSTITUTION:A tin plated steel plate which is plated with tin at a quantity fairly smaller than that of conventional blank materials, that is, 0.05-2.80g/m<2> and has 0.2-4mu average surface roughness is subjected to drawing and shear- spinning between a punch and a die. The steel plate is shear-spinning at 40-80% rate. If desired, the tin plating layer on the surface in the end barrel part 2 of a can body 1 where the iron surface of a constant area ratio exposes is heat- treated whereby it is converted to a tin-iron alloy layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drawn and ironed can made of a surface-treated steel plate and a method for manufacturing the same, and more particularly, the present invention relates to a drawn and ironed can made of a surface-treated steel plate, and more specifically, the tin plating amount is reduced compared to a drawn and ironed can made of a conventional tin-plated steel plate. The present invention relates to a drawn ironing can which has significantly improved paint adhesion and corrosion resistance while maintaining it at a low level, and a method for producing the same.

The product obtained by drawing the metal material between a punch and a die and then ironing it has a good appearance and a smooth bottom with no seams in the can body or the connection between the can body and the can bottom. It does not require operations such as tightening the lid or forming seams, and the can body has a thinner wall, so it has the advantage of requiring less metal material, making it suitable for applications such as beverage canning. Widely used.

The metal material of this drawing and ironing mm must naturally be a material with good workability, and from this point of view, relatively expensive metal materials such as aluminum plates and tin-plated steel plates (Purikin) are generally used.

Among these materials, tin-plated steel sheets have the problem of depletion of tin resources, and as a result, the cost of tin increases year by year, which is an economic constraint, so the amount of tin plating is reduced as much as possible. This is desirable.

However, the tin plating layer acts as a solid lubricant during drawing and ironing of tin-plated steel sheets, and as a protective coating layer against corrosion of the mounted body after processing. Attempts to reduce the amount of plating are subject to limitations from the viewpoints of processability and corrosion resistance. Thus, currently, tin-plated steel sheets for drawing and ironing are
#50 to #100 tin plate (tin plating amount 5.6 to 1
12 f/d) is in practical use.

The present inventors have developed a metal material for drawing and ironing that has a tin plating amount of 0.05 to 2, which is considerably smaller than conventional materials.
．． 80t/lr? C In this specification, when a tin-plated steel plate is used within the range of 100% and the surface roughness of the chainsaw-plated steel plate is selected to be within a certain range, K becomes the can body during drawing and ironing. A certain area ratio of the iron surface is exposed on the surface, which is completely unexpected.Compared to a can body made of a tin-plated layer where such iron surface is not exposed17, the adhesion of the paint is actually improved. , as a result of which the corrosion resistance is significantly improved, and thus the corrosion resistance K
Using low-cost metal materials, the
Moreover, it has been discovered that it can be manufactured with high productivity.

That is, the object of the present invention is to maintain the amount of tin plating at a significantly lower level compared to conventional drawing ironing made of tin-plated steel sheets, while significantly improving paint adhesion and corrosion resistance. K provides a method for producing the same.

Another object of the present invention is to maintain the surface of a metal material for drawing and ironing in a state of a metal tin plating layer sufficient to exhibit a sufficient solid lubricant action during drawing and ironing.
On the other hand, it is an object of the present invention to provide a method for producing a drawn and ironed can in which a surface having excellent paint adhesion and corrosion resistance is formed on the can body after the drawing and ironing process is completed.

According to the present invention, the can body is obtained by applying a drawing and ironing process to a surface-treated steel plate, and comprises a relatively thick can bottom and a relatively thin can body. In a drawn ironing can that does not have a joint between the bottom of the can and the bottom of the can,
The can body of the Mukuyoshi-shigoki can is 0.01 to 1.709/m.
” has a surface layer containing tin, and the surface layer has an exposed area ratio of 1.
Provided is a drawing and ironing can made of a combination of a 5 to 80 iron surface and a tin-iron alloy layer and/or a tin plating layer, and the bottom surface of the can is made of a tin plating coating layer. .

According to the present invention, furthermore, in the drawing and ironing manufacturing method, which comprises subjecting a tin-plated steel plate to drawing and ironing between a punch and a die, the tin-plated steel plate has a tin plating amount of 0.05 to 2. ,809/rr? Using a tin-plated steel plate with an average surface roughness of 0.2 to 4 microns, ironing is performed at an ironing rate of 40 to 80, and if desired, the tin-plated layer on the surface of the cup side wall is replaced with a tin-iron alloy. Provided is a method for producing a drawn and ironed can, which comprises performing heat treatment for converting the material into a layer.

The present invention will be described in detail based on specific examples shown in the accompanying drawings.

In FIG. 1-A showing the overall structure of the squeezer of the present invention, this integral body 1 consists of a can body section generally designated by 2 and a IIJiiE section generally designated by a drawer. This - the side surface of the body 2 and the connection part 4 between the can body 2 and the can bottom 6
There are virtually no seams.

The can body 2 is formed by drawing a metal material between a punch and a die, then punching it, as described in detail, and as a result, its thickness is greater than that of the can bottom 3. The meat is thin.

At the upper edge of the can body 2, if desired, a 7-thick groove is provided through the neck 5, and it is possible to tighten the VC211 between it and the peripheral edge of one end member (not shown). It has become. In addition, there is a spherical clear protrusion (dome) 7 on the bottom part 6 of the can.
are provided inward to prevent the bottom part 3 of the can from protruding outward due to the pressure of the contents, thereby improving the sitting comfort of the can.

An important feature of the drawing and ironing can of the present invention is that the surface of the can bottom 30 is made of a tin-plated coating layer, whereas the can body 2 is made of a tin-plated coating layer.
1 to 1.70r/ff1”, special [0,1 to 1.5f
/- has a surface layer containing significantly less tin, and this surface layer has an exposed area ratio of 15 to 809! In particular, it consists of a combination of a 25 to 60% iron surface and a tin-iron alloy layer and/or a tin plating layer.

That is, in the present invention, the above-described amount of tin in the can body 2 exists in the form of a tin-iron alloy layer or a tin plating layer, but from a microscopic perspective, this iron surface that does not contain tin is exposed. A notable feature is that

Conventionally, in the field of canning cans, various types of surface-treated steel sheets have been used in order to suppress iron elution into the contents. Exposure is considered undesirable.

On the other hand, according to the present invention, by exposing the tin-plated steel plate or the iron surface of a certain area ratio, it is possible to improve the adhesion of the paint. This will become clear by plotting the relationship between the area ratio and the beer strength of the coating film and referring to FIG. 4.

Moreover, the conventional tin-plated steel sheets for drawing and ironing have a relatively large amount of tin plating, as already mentioned above.
According to the present invention, the total amount of tin present on the surface of the drawing and ironing can can be reduced to a significantly lower level compared to conventional ones, and it can be easily drawn and ironed without impairing workability.
Furthermore, the paint adhesion and corrosion resistance of the product can be significantly improved.

In FIG. 2 showing an enlarged cross-section of the can bottom 3, the bottom wall 6 includes a steel plate substrate 8, a tin-plated coating layer 9, and a tin-iron layer that is optionally interposed between the substrate 8 and the tin-plated coating layer 9. It consists of an alloy layer 10. This can bottom 3 has not been drawn and ironed, so the tin content is the same as the material, 0.05 to 2.80 fed, and the average surface roughness is 0.2 to 4 microns. within the range of

In Figure 6-A, which shows an enlarged example of the surface structure of the can body 2, the side wall is made up of a copper plate substrate 11 and a metal tin layer 12 on a steel plate substrate, and microscopically speaking, it is partially made of iron. An exposed surface 16 is present. In FIG. 3-B showing another example of the surface structure of the can body 2, this side wall is formed by the steel plate substrate 1.
1. Consists of a tin-iron alloy layer 14 on a steel plate substrate, microscopically speaking, there is a partially exposed iron surface 1 between the tin-iron alloy layers.
6 still exists. In some cases, a metal-deficient tin layer 12 is present on the tin-iron alloy layer 14.

In this specification, the exposed area ratio of the iron surface of the can printing side wall 2 and the tin-iron base metal layer is a value obtained by the following measuring method. That is, using a Bote/Geostat (constant voltage electrolyzer), using a saturated calomel electrode as a reference electrode, platinum as a counter electrode, and adjusting the pH to 95 with sodium hydrogen carbonate *0.05N anhydrous sodium carbonate aqueous solution, a fixed area was The surface of the can body of the object to be measured is first polarized from -200 mV to -1450 txr, then -1450 rPLV.
Polarize from +550 mV to +550 my, and finally polarize from +550 mV to -1300 mV while obtaining a polarization curve. In either case, polarization is continued at a constant rate of 1000 mV/min. This polarization curve is shown in FIG. Note that, prior to measurement, a pre-operation is performed as necessary to remove dirt, oxidation layer, and surface treatment film on the surface of the object to be measured.

One VC peak was observed between -450 and -800 mV in this polarization curve, and this was caused by the sum of the iron surface and the tin-iron alloy. -1000FJ of this polarization curve
A maximum of three peaks were observed between LI/ and -1250 mF, the first peak appearing is tin, the second peak is iron, and the sixth peak is caused by tin-iron alloy.

These peaks can be seen by taking the above polarization curves of pure substances and their known mixtures.

As shown in Fig. 4, the exposed area ratio S of the tin-iron alloy layer appears around -1150 mV, and the tin-iron alloy layer of the tin -
If the peak height of the iron alloy layer is A, fim/-, then 5A = Q, 21 x A, ? Defined in [H].

Since the peak of iron from -1000mF to -1250mF is not quantitatively accurate, the exposed area ratio 5B of the iron surface is calculated by using the peak height of -450 to -800mV in Figure 4.
As tJ7'nl, 5B=0.52 (hp-Q, 1
4xi').

In the present invention, the area ratio of the exposed iron surface is 15 to 80 *
1 In particular, the fact that the area ratio is in the range of 25 to 60% may also be overlapping. In other words, if this area ratio is smaller than the above range, a remarkable improvement in coating film adhesion can be expected. Increasing the amount more than the range is not good from a processing standpoint or from the standpoint of preventing rust.

K for manufacturing the drawn and ironed can of the present invention has a tin plating amount of 0.
, 05 to 2.80 f/m', and the surface that becomes the outer surface of the ironing can is 1.00 to 2.80 f/m'. , and the inner surface is 0.05 to 2.801/lr? and the average surface roughness Hα) is 0.2 to 4 microns,
In particular, it is important to use a tin-plated steel plate in the range of α5 to 2 gigrons.

In the present invention, when the plating amount is less than the range mentioned above, the drawing and ironing workability tends to decrease significantly.On the other hand, when the plating amount is less than the above range and the paper is more than the above range, the surface becomes #
It becomes difficult to expose iii. In addition, surface roughness is also related to both iron surface exposure and workability9, and when the roughness is smaller than the above range, workability with a low plating amount decreases, and the iron surface exposure also falls within the scope of the present invention. If the roughness is more than 4 degrees above the above range, too much iron surface will be exposed, which is likely to cause deterioration in workability and poor appearance of the can.

The tin-plated steel plate used is a low-carbon rolled steel plate electroplated with tin in the amount described above, and this tin-plated steel plate is preferably a matte plate (no-reflow plate) that remains as plated for 7 tons. It is desirable that melt treatment is performed after plating.
Even a t-performed reflow plate can be used for the purpose of the present invention if its roughness is within the above range.

In order to expose the iron surface on the body wall, it is also necessary to perform drawing ironing at a certain ironing rate or higher, which is 40 to 80
It is preferable to perform the processing at an ironing rate of 1%, especially in the range of 50 to 7096.

In the drawing and ironing of the present invention, the ironing rate (RD) is defined as the thickness of the can bottom 6 being D1 and the thickness of the can body 2 being d.
Defined by Eq. It is desirable that the thickness of each of these parts be in the range of D=0.27 to Q, 50m d=0.080 to 0.220m.

The drawing and ironing process can be easily carried out by means known per se, using a combination of a punch and a die, which are known per se, and supplying a lubricant between the material and the die, if necessary. Although the drawing and ironing process may be performed in one stage, it is generally desirable to perform the drawing process and ironing process in multiple stages.

In this way, the side wall of the nine cups receives the drawing and ironing process.
-A or 3-BfgK surface texture is shown.

A cup having the surface texture shown in FIG. 3-A can be used as the 11th can, but if desired, this cup may be heat-treated to remove part or all of the remaining tin plating layer.
It can also be converted into a tin-iron alloy layer showing AK and made into a can.

According to this aspect of the present invention, rather than allowing the thinned tin plating layer to partially remain on the surface as it is, the tin plating layer is converted into a tin-iron alloy layer by heating. By doing so, it is possible to actually improve the adhesion of paint etc. and the corrosion resistance. In this case, the tin-iron alloy layer is formed by thermal diffusion of metallic tin as a plating layer and iron as a substrate, but the overlap is such that the iron surface is not excessively converted to VcfII. For this purpose, the heat treatment must be performed at a temperature of 150C or higher but not exceeding the melting point of tin (232C), and for a period of 15 seconds to 10 minutes.
more easily done. Prevents excessive oxidation or rust on iron surfaces,
Or as a friend to prevent pitting of steel surfaces due to contents, IJ
In some cases, it may be advisable to passivate the exposed portion of the iron surface by applying a general surface treatment such as salt treatment, chromic acid treatment, or chromic acid treatment.

The obtained T-cup is trimmed, subjected to operations such as degreasing and cleaning if necessary, and then painted or printed on the inner or outer surface, dried, and baked. Next, 1R or multi-stage neck-in processing is performed, and finally, flange processing is performed to obtain the final mounted body. In some cases, the bell body is also processed with beads, etc.

The drawn and ironed can according to the present invention has excellent paint adhesion, and even when subjected to bead processing of the bell body or multi-stage neck-in processing of two or three stages, cracks and holes will not occur in the paint film. The paint adheres well to the underlying metal, and the degree of metal exposure is negligible from the perspective of the contents.
It is also a significant advantage of the present invention that a can with excellent corrosion resistance is obtained.

The invention is illustrated by the following example.

Example 1゜Single plate thickness 0. ' 52 wm, hardness 7"-21/2, surface roughness Ra 1μ, tin coating amount 1.7f/mu (inner v outer surface) A matte plated steel plate was punched into a disc with a diameter of about 145", according to the usual method. The inner diameter between the aperture punch and the aperture die is approximately 72-
Form into a small lump shape.

Next, it was ironed using a combination of ironing punch and ironing die. The dimensions and physical properties of this shell are as follows.

Bottom wall thickness CD) 132■ Trunk wall thickness <c
l) 0.09 discipline rate
72- Partial inner diameter 65.4M Neck-in part inner diameter 6tO Partial height 122 Iron exposed area ratio 6591 After degreasing and cleaning the inside and outside of this can body, it was painted with epoxy area paint. The m* adhesion was 0.3 to α5Kt15■ at 180° beer strength.

After neck-in processing, it was filled with carbonated drinks (cola) and canned, then stored at 50 CIC. Open after 1 month and 6 rows,
A box used to observe the inside of a chisel.

As a result, an integral part of the present invention can be used not only after one column but also after six columns.
Even after storage for months, no pitting corrosion was observed on the bell body, and no abnormalities such as peeling of the paint film were observed. In addition, in order to evaluate the adhesion with the external paint, the contents of a carbonated beverage containing low fruit juice were filled into a can with a white coat and finishing varnish applied to the outside surface of the can, and the contents of the can were filled (after being canned). -Alternatively, the product of the present invention was subjected to heating and heat sterilization treatment using a bust riser, etc., but even after undergoing these heat cycles, the white coat and finishing varnish did not peel off and there was no abnormality.

Furthermore, in order to clarify the superior effect of the present invention, a control sample other than the present invention was prepared in the same manner as in Example 1, except for the following changes.

(1) Control unit A Surface roughness RaQy 1μm, tin adhesion amount 11.2f/l?
(2) Control integral B The same as in Example 1, except that the prite material was used as a bright material with a surface roughness Ra[) of 1 μm and a tin adhesion amount of 5.6 f/d. The two types of control bodies similar to those of Example 1 and the body of Example 1 were compared and evaluated in terms of iron exposed area ratio and coating film adhesion (180° building strength) on some of the inner surfaces.

As is clear from the above comparison results, it was confirmed that the exposed area of iron affects the coating adhesion, and it is clear that by selecting it within the scope of the present invention, an excellent integrity can be obtained. .

Example 2゜ A bell body was prepared by drawing and ironing a blank plate with a surface roughness Rts of 2 μm by setting the tin adhesion amount on the inner and outer surfaces to 1.70 f/m' on the outer surface and 0.5 f/d on the inner fit. An integral piece was made using the same process as in Example 1, and when the adhesion of the coating on the inner surface was measured, it showed a strength of 1.0 go/5 m or more.

When coated with epoxy/phenol paint, the adhesion of the film is 3.5 kg/5 ms or more for the inner surface and 15 kg/5 ms for the outer surface.
Strong over Kg15m! lft shown〇The iron exposed area ratio at this time is 35% on the outer surface and 60% on the inner surface.
Next time.

Example 6: In addition to evaluating the content resistance suitability, the m4 of Example 1 and the can bodies of Controls A and B were washed with bales, pH 4.5, concentration 2. Spray a sodium salt solution of s% of phosphoric acid at 800 for 20 seconds on some of the inner and outer surfaces of the barrel to form a ring coating on the iron 1i.
Iif passivation and next. After that, I painted M4 with Evokisuria paint.

Fill these containers with the contents and beverages (cola type, citric acid type), store them in a 50C storage room for 6 months, open them 7 times, measure the amount of dissolved iron, and measure the pores. I observed the food situation.

- The corroded parts of these m4 cola-based contents were near the seaming part of the neck-in part and the seaming process part.

The pitting corrosion occurred near the seaming of the neck-in part.

From the above results, it was confirmed that the integrated product of the present invention had sufficient can performance with no abnormalities observed even in terms of content resistance.Example 4, base plate thickness 0. ! 121111, hardness T -21/2, surface roughness Ra015μ expanded tin adhesion amount 2.2f/rr? A bright plated steel plate (both inside and outside) was processed and painted using the same 11KL method as in Example 1. At this time, the iron exposed area ratio was 30%.
Paint film adhesion at 180° building strength is 0.4fi15
■I am very happy with this.

Example 5゜ 6R neck-in processing was performed on the m4 coated with epoxy phenol based on Example 2, and the pole after neck-in was 57
After processing into (1) and filling it with charcoal beverage (cola type), it was stored at 50C for 6 months and then opened and evaluated. As a result, pitting corrosion does not occur. Further, the amount of dissolved iron was 0.4 pp, and the inner surface coating was in good condition with no abnormalities observed.

Example & Example 2 A bead was inserted into the m4 coated with the epoxy phenol paint of Example 2, and the diameter after neck-in was processed to 61 mm. I filled the can with 5096 orange juice, filled the head space with nitrogen, and sealed the lid. 6 at 57C
After storage for a month, the opening was evaluated. Dissolved amount of iron I PP town dissolved amount of tin 0. IPP" or less, and the inner surface was in good condition with no abnormalities such as lifting of the Ii! film.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the overall structure of the drawing and ironing can of the present invention; 3-A Zusha, an enlarged view of an example of the surface texture of a part of the drawing and ironing can in Fig. 1, and Fig. 5-8 is an example of the surface structure of the drawing and ironing can in Fig. 1. A diagram showing an enlarged view of another example of the surface texture of L, No. 4@sha, - A polarization curve showing the relationship between the polarization of the shell surface and the amount of reduction current, where reference numeral 1 indicates one piece, and 2 indicates one part. , 6 is the bottom of the can, 4 is the connection between the part and the bottom of the can, 5Fi neck, 6 is the flange,
7 is a dome, 8 is a steel plate substrate, 9 is an eroded layer, 10 is a tin-iron alloy layer, 11 is a steel plate substrate, 12 is a metal tin layer, 16 is an exposed iron surface, and 14 is a tin-iron alloy layer. . Toyo Seikan Co., Ltd. Inner Section 3-B Inner Section Figure 4

Claims (2)

[Claims] (1) It is obtained by drawing and ironing a surface-treated steel plate, and consists of a relatively thick can bottom and a relatively thin can body. In a drawn ironing can that has no seam at the connection part with the bottom, the can body of the drawn ironing can has a surface layer containing tin of 0.01 to 170 f/-, and the surface layer has an exposed area ratio. is 15 to 809
A drawing and ironing can comprising a combination of an iron surface (g), a tin-iron alloy layer and/or a tin plating layer (i), and a bottom surface of the can comprising a tin plating coating layer. (2) In a method for producing a drawing and ironing can that involves subjecting a tin-plated steel plate to drawing and ironing between a punch and a die, the amount of tin plating is 0.0 as the tin-plated steel plate.
5 to 2.80 fAt? and the average surface roughness is 12
Use a tin-plated steel plate with a thickness of 4 to 4 microns, and the ironing rate is 4.
1. A method for manufacturing a drawn and ironed can, which comprises performing ironing from 0 to 80°, and optionally performing a heat treatment to convert the tin plating layer on the surface of the side wall of the cup into a tin-iron alloy layer.