JPS5841152B2 - Metal containers and their manufacturing method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When forming joints of metal containers, particularly side seams of the can body of three-piece cans, the present invention provides an inert gas atmosphere in which the moving metal container is sprayed immediately after electric resistance welding. The present invention relates to a metal container formed with a side seam that does not form an oxide film of a predetermined thickness or more on the surface when exposed to water, and a method and apparatus for manufacturing the same.

The means for high-speed and continuous electric resistance welding of the joints of metal containers of this type is to pass the weld between a pair of upper and lower electrode rollers, or to pass between a pair of upper and lower electrode rollers via an electrode wire. However, in both cases, when high-temperature resistance heating is concentrated on the seam to melt the lapped surface, an oxidation reaction with the oxygen atmosphere surrounding the seam is inevitably excited, resulting in a unique color depending on the thickness of the film formed on the seam surface. Coating with an oxide film is well known.

This is caused by the interference of reflected light in the oxide film, and follows the principle of light interference in general thin films.

Table 1 shows the degree of oxidation of the metal and its reflected light.

The oxidation of metals, which is a factor in the formation of film thickness, causes rust at room temperature, but the rate of oxidation is not that great, but at high temperatures of over 550 degrees Celsius due to resistance welding heat, the oxidation reaction occurs violently, and the seams easily form. This naturally causes discoloration as shown in the table.

However, the discolored welded seams look different from the other parts, which have the unique color and luster of the surface metal material, which impairs the aesthetics and reduces the consumer's desire to purchase, which is the biggest bottleneck in the dissemination of the product as a practical product. .

In addition, the thickness of the oxide film that forms on the seam surface exhibits the characteristic color shown in the table above, and the thicker it becomes, the more difficult it is for the transparent paint to coat the seam in the subsequent process. Worse still, during subsequent process work (by Franscher, Netsker, Seamer, etc.), the oxide film often peels off together with the correction coating, exposing the base metal, which only leads to metal elution and container corrosion. Moreover, it has been found that the oxide film looks bad and leads to quality deterioration.

Therefore, the biggest technical difficulty that must be overcome for the widespread practical use of the welded metal container is how to reduce the thickness of the oxide film that inevitably occurs during welding, which inhibits the inherent color and luster of the surface metal material itself. It depends on whether the control is suppressed to the extent that it does not deteriorate the processing adhesion of the correction coating.

In view of the above-mentioned conventional drawbacks, the present invention provides a metal container which is exposed to an inert gas atmosphere immediately after electric resistance welding in order to suppress the oxide film formed on the joint surface to below a certain level, and a method and apparatus for manufacturing the same. It is something.

The method for manufacturing a metal container of the present invention involves applying electric resistance welding to the seam that does not produce an oxide film of a thickness greater than a certain thickness that impairs the unique color and luster of the metal material itself. The basic idea is to place the welded seam under special environmental conditions that cut off contact with the oxygen atmosphere and forcibly cool the welding temperature to below the oxidation reaction promotion temperature (for example, below 550'C). In an inert gas atmosphere that also serves as a cooling medium, the lap seam is electrically resistance welded by passing between a pair of upper and lower electrode rollers or between a pair of upper and lower electrode rollers via an electric wire, and the seam surface is coated with a film thickness of at least a predetermined thickness. This prevents the formation of an oxide film.

A first embodiment of the apparatus of the present invention applied to metal cans will now be described with reference to FIGS. 1 to 3.

The manufacturing apparatus A of the present invention includes an upper electrode roller 3 fixed between the forked ends 1a and 1b of a drive roller shaft 2 which is rotatably supported through the forked ends 1a and 1b of the lower end of the hanging bracket 1, and an upper electrode roller 3 fixed between the forked ends 1a and Ib of the A bifurcated end 4a at the end of a guide rod 4 for externally guiding the can body β held by wrapping the side seam α.
, 4b, which is attached to a fixed shaft 5 fixed through each other so as to be freely rotatable, and the feed line L of the side seam α over a predetermined section immediately after passing between the upper and lower electrode rollers 3 and 6 of the side seam α. 8 groups of 7° inert gas blowing nozzles arranged vertically in a line facing each other are provided.

In the figure, reference numeral 9 denotes a drive wheel which is fixed to the end of the drive roller shaft 2 and transmits torque by wrapping an endless chain or an endless belt 10 around it.

The upper and lower blowout nozzle groups 7.8 have a bifurcated starting end 11a,
11b straddles one side of the upper electrode roller 3 and connects the forked ends 1a and 1b of the hanging bracket 1 to the front side of the lower part) 12, 13
The lower surface of the upper gas distribution box 11, which is fixed at right angles to the hanging bracket 1 and cantilevered over the entire length of a predetermined section horizontally, and the T-shaped end 14a at the starting end are connected to the bifurcated ends 4a, 4 of the guide rod 4.
b, fixed with bolts 15, 16 across the tip, and cantilevered over the entire length of a predetermined section parallel to the upper gas distribution box 11. The degree of directivity between the rollers 3 and 6 is large, and the rollers are arranged opposite to each other in a staggered manner.

Furthermore, the right-angled bent end of a supply pipe 17 that hangs down vertically and communicates with the internal gas chamber 11c is connected to the upper end of the upper gas distribution box 11 with a nut 18, and the end of the upper gas distribution box 14 is connected with a nut 18. A guide rod 4 and an internal gas chamber 14 are installed at the bottom of the surface, extending along the lower side of the gas distribution box 14.
The folded end of the supply pipe 19 communicating with c is connected with a nut 20.

A second embodiment of the device of the present invention will be described with reference to FIGS. 4 to 6.

The apparatus B of the present invention includes the apparatus A of the first embodiment,
The left and right side plates 21 and 22 extend from the starting end to the vicinity of the ending end of the opposing halves of both outer surfaces of the upper and lower gas distribution boxes 11 and 14, respectively.
23 and 24 are attached in parallel respectively to the upper and lower blowout nozzles 7.
．． The left and right side plates 21 and 2 extend protrudingly on both sides of the 8th group.
End plates 25 and 26 are interposed between the terminal ends of 2, 23 and 14, respectively, while upper and lower brush walls 27.
28 are flocked, and the opposing ends are abutted and closed so that the side seam α portion can freely pass through, so that the inert gas ejected from the upper and lower blow-off nozzle groups 7 and 8 is sealed off as outside air.

``Also, if necessary, the mutually opposing surfaces 11e, 14e at the terminal ends of the upper and lower gas distribution boxes 11, 1''4 are curved with both sides projecting out in a cross-sectional shape corresponding to the inner and outer shapes of the side seam α and its surrounding area, and formed into an arc-shaped shape. It is also possible to form a passing gap P, but in that case, the end plates 25, 26 and the end brush wall that is flocked thereto may be omitted.

A third embodiment of the device of the present invention will be described with reference to FIG.

In the device C of the present invention, in place of the upper and lower brush walls 27, 28 in the device B of the second embodiment, left and right side plates 21, 22,
The nozzle holes 29, 30, 31, 32 are opened in the opposite end faces of the end plates 23, 24 and the end plates 25, 26, and communicate with the gas chambers 11C, 14C of the upper and lower gas distribution boxes 11, 14, respectively. 23, 24 and the end plate 25, 26 to emit air from the upper and lower blowout nozzles 7 and 8 at the same time as the nozzle hole 2.
Inert gas is also ejected from 9.30 and 31.32 to form a gas curtain 33 that continuously surrounds both sides and the end, leaving no room for outside air to enter.

A fourth embodiment of the device of the present invention will be described with reference to FIGS. 8 to 10.

The apparatus of the present invention, E, and F correspond to the inner and outer shapes of the side seam α and its surrounding area, respectively, extending continuously over the tips of the upper f blowing nozzles 7 and 8 in the apparatus A of the first embodiment. Seven-F kite covers 34 and 35, each having opposing surfaces 34a and 35a formed in their cross-sectional shapes, are integrally attached to the inert gas induction gap 36 and are mounted opposite each other. Groups of blow-off ports 37 and 38 communicating with the groups of upper and lower blow-off nozzles 7 and 8 are opened in 35a, respectively, so that the inert gas ejected from the blow-off ports 37 and 38 is guided to the guide gap 36 and drawn out to both sides. It will be configured.

Note that FIG. 8 shows the case of a round can body β1, and FIG. 9 or 10 shows the case of a square can body β2. The case of β3 is shown respectively.

However, when it is sufficient to prevent the formation of an oxide film only on the outer surface of the side seam α, as in the case of dry pack welded cans,
Lower gas distribution box 14 blowout nozzle 8 groups, left and right side plates 23, 24,
Lower brush wall 28. Needless to say, the lower guide cover 35 is not required at all.

Since the present invention is constructed as described above, prior to welding work, an intermediate supply pipe 17 is supplied from an inert gas source (not shown) in advance.
, 19 to the gas chamber 11 of the upper and lower gas distribution boxes 11.14.
c, 14c is supplied with inert gas from the upper and lower blow-off nozzles 7 and 8 groups or the blow-off ports 37 and 38 groups on the outlet side of the metal container that moves at the same time as the storage and toward the feed line L of the side seam α. The inert gas is ejected at a set pressure of 0.1 to 20,771 inches/hour to stagnate and float in a predetermined section of the front and rear feed line L between the upper and lower electrode rollers 3 and 6 to create a stable inert gas atmosphere. .

The can body β, which has a circumference r under these environmental conditions and holds the side seam α by wrapping, is wrapped around the guide rod 4 and transported in the direction of the arrow at a conveyance speed of about 7 m/min or more, for example, about 1 on/min. When feeding and passing between the upper and lower electrode rollers 3 and 6, the upper and lower electrode rollers 3 and 6 become electrically connected through the side seam α, generating high-temperature resistance heat and melting and joining the lap surfaces. The starting end of the side seam α begins to penetrate into an inert gas atmosphere that cuts off contact with the outside air, and in a predetermined section along the feed line L after passing between the upper and lower electrode rollers 3 and 6, the upper and lower blow-off nozzles 7 and 8 groups or the upper and lower Air outlet 37.3
Inert gas is sprayed from the 8th group onto the inner and outer surfaces of the side seam α, and the inert gas is forced to cool down to a temperature that does not promote the activation of oxide film formation, while passing through an inert gas atmosphere.Then, the side seam α is subjected to a coating film correction process. Send.

The second to fourth embodiments of the present invention have upper and lower brush walls 27 and 28.
The gas curtain 33 and the upper and lower guide covers 34 and 35 completely isolate the air from the outside air, so the effect is remarkable.

Here, various experimental comparisons will be made between the case of the present invention in which lap seam welding was performed in an inert gas atmosphere and the conventional case in which lap seam welding was performed in the atmosphere.

(1) In the case of the present invention The present invention is made of beam flow tinplate (plate thickness 0.23 mm, plating amount #25 - outer surface side Free Sn amount 2.129 /
m, alloy Sn amount 0.60g/m), chromium-treated steel sales (
Chromium oxide 15■/m', metal chromium 100■/m
2) Seam welding was performed under the following welding conditions in a N2 gas stream using a black plate (from which the surface chromium layer of chromium-treated steel was peeled off), and then the oxide film thickness appearance (reflected light) and adhesion of the welded area were measured. The properties, processing adhesion, and chemical resistance were measured.

The measurement method was as follows.

(2) Oxide film thickness Using an ESCA (X-ray photoelectron spectrometer), measure the oxide film thickness based on the element concentration ratio of Sn and 0°Fe while etching the surface with Ar gas.

■ Appearance Visually observe the oxide film thickness.

■ Apply nylon powder to the welded area as an adhesive paint and apply 300~
Baked at 320℃, 15~20SeC, thickness approx. 80~10
A coating film of 0μ is formed and used as a sample.

This coating film is forcibly peeled off from the board and the adhesion is visually observed to see if the oxide film has migrated to the coating side.

(2) Two types of adhesive paints, epoxy powder and epoxy urea solvent-based paint, are used, and the epoxy powder is used to form a coating film with a thickness of approximately 40 μm under the same method conditions as in (2) above.

Also, epoxy-based solvent-based paints are applied with a brush2.
Baking is performed at 80° C. for 10 seconds to form a coating film with a thickness of about 13 to 15 μm, which is used as a sample.

Each sample was bent into a U-shape, and microcracks occurring in the coating at the processed area were observed under a microscope to check the adhesion of the process.

■ A sample prepared using the same method and conditions as in ■ above using epoxy powder as a chemical-resistant paint was immersed in Glastar sol, which is the most corrosive type of aerosol product, and heated at 50°C for 1 hour.
Store it for several months and observe the bubbles that form under the coating over time to check its chemical resistance.

(2) In the case of the conventional example The conventional example is the same material and the same welding conditions as the present invention, but
Seam welding was performed in the air without using N2 gas, and the oxide film thickness, appearance, adhesion, processing adhesion, and chemical resistance were measured under the same method conditions.

The results are shown in Table 2.

In addition, ◎ is the best, ○ is good, × is poor, and xx is extremely poor, respectively.

As described above, it is recognized that seam welding in a N2 gas stream produces a thin oxide film for all materials, and that the appearance, adhesion, processing adhesion, and chemical resistance are excellent.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing the first embodiment of the present invention, Fig. 2 is a partially cutaway enlarged sectional view taken along the line ■-■ of Fig. 1, and Fig. 3 is a schematic side view showing the first embodiment of the present invention.
FIG. 4 is a schematic side view showing the second embodiment of the present invention, FIG. 5 is an enlarged end view as seen from FIG. FIG. 4 is an enlarged sectional view taken along line VI-VT, FIG. 7 is an enlarged sectional view of a portion corresponding to FIG. 4 taken along line VI-VI, showing a third embodiment of the present invention, and FIGS. FIG. 6 shows enlarged cross-sectional views of main parts of the fourth embodiment. A-F...Metal container manufacturing equipment, L...
・Feed line, α...Side seam, β,
β1. β2゜β3...Can body, 3,6...
・Upper and lower electrode rollers, 7°8...Upper and lower blowing nozzles, 27, 28...Upper and lower brush walls, 29,3
2... Upper and lower nozzle holes, 33... Gas curtain, 34, 35... Upper and lower guide covers 34
a, 35a... opposing surface, 36... guiding gap.

Claims (1)

[Claims] 1. The thickness of the oxide film formed on the surface is at least 400 mm.
A metal container in which the aesthetic appearance of the seam and the processing adhesion of a corrective coating film are significantly improved by forming an electric resistance welded seam which retains as much as possible the inherent color and luster of the surface metal material itself. 2. The metal container according to claim 1, wherein the seam is a side seam of the body. 3. While the can body is being transported at a speed of 7 m/min or more, the weld seam is exposed to an inert gas atmosphere immediately after electric resistance welding, and the thickness of the oxide film generated on the weld seam surface is suppressed to at least 400 Å or less. A method for manufacturing metal containers. 4. The method for manufacturing a metal container according to claim 3, wherein the welded seam is a side seam of the body. 5. The method for manufacturing a metal container according to claim 3 or 4, wherein the inert gas is nitrogen gas, argon gas, or carbon dioxide gas. 6. The method for manufacturing a metal container according to claim 3, 4, or 5, in which electric resistance welding is performed using a pair of upper and lower electrode rollers. 7. The method for manufacturing a metal container according to claim 3, 4, or 5, wherein the electric resistance welding is performed using an electrode wire. 8. The inert gas atmosphere is created by continuously spraying an inert gas in a predetermined section along the flow of the side seam immediately after passing between the upper and lower electrode rollers.
A method for manufacturing a metal container according to paragraph 5, paragraph 6, or paragraph 7. 9. The method for manufacturing a metal container according to claim 3, 4, 5, 6, 7, or 8, wherein the inert gas atmosphere is sealed and isolated from outside air. . 10. The method of manufacturing a metal container according to claim 8 or 9, wherein the inert gas is sprayed from both or one of the inner and outer surfaces of the side seam. 11 The thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400λ or less, and an inert gas is applied along the upper side of the feed line of the side seam over a predetermined section immediately after the side seam passes between the upper and lower electrode rollers. Metal container manufacturing equipment consisting of a group of blowing nozzles oriented downward. 12. The apparatus for manufacturing a metal container according to claim 11, wherein the 12 blowing nozzle groups have a greater directivity with respect to the upper and lower electrode rollers as they are closer to the starting end of the predetermined section. 13 The thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400A or less, and immediately after the side seam passes between the upper and lower electrode rollers, over a predetermined section, the feed line of the side seam is sandwiched between the upper and lower sides. A metal container manufacturing device comprising a group of inert gas blowing nozzles arranged in opposition. 14. The apparatus for manufacturing a metal container according to claim 13, wherein the 14 blowing nozzle groups have a larger directivity with respect to the upper and lower electrode rollers as they are closer to the starting end of the predetermined section. 15. The metal container manufacturing apparatus according to claim 11 or 12, wherein the upper and lower blow-off nozzle groups are arranged opposite to each other in a staggered manner. 16 The film thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400 Å or less, and is arranged downward along the upper side of the feed line of the side seam over a predetermined section immediately after the side seam passes between the upper and lower electrode rollers. A manufacturing apparatus for a metal container, which includes a brush wall that surrounds a group of inert gas blowing nozzles in parallel along both sides thereof to block and confine the inert gas blown from the inert gas blowing nozzle group from the outside air. 17 The thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400 Å or less, and the side seam is vertically opposed over a predetermined section immediately after passing between the upper and lower electrode rollers with the feed line of the side seam sandwiched therein. Upper and lower brush walls are provided parallel to and surrounding both sides of the arrayed inert gas blowing nozzle group, and the upper and lower brush walls abut and close opposite ends so that the side seam portion can freely pass through, and the upper and lower brush walls are closed so that the inert gas blowing nozzle group can pass through the upper and lower brush walls. Equipment for manufacturing metal containers that seals and seals blown inert gas from the outside air. 18 The thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400A or less, and the side seam is vertically opposed over a predetermined section immediately after passing between the upper and lower electrode rollers with the feed line of the side seam in between. Upper and lower brush walls are provided that continuously surround both sides of the arrayed inert gas blowing nozzle group and the end of the predetermined section, and the opposing ends of the brush walls are abutted and closed so that the side seam portion can freely pass through, and the inert gas A metal container manufacturing device that seals inert gas blown out from a group of blowing nozzles by blocking it from the outside air. 19 The thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400 Å or less, and the side seam is applied over a predetermined section immediately after the side seam passes between the upper and lower electrode rollers, along the upper side of the feed line of the side seam, and and a guide cover with a downward facing surface having a cross-sectional shape corresponding to the outer shape of the surrounding area, and a group of inert gas outlets are opened in a straight line along the surface of the guide cover facing the feed line. Equipment for manufacturing metal containers made of tar. 20 The film thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400 Å or less, and from immediately after the side seam passes between the upper and lower electrode rollers, over a predetermined section, the feed line of the side seam is sandwiched between the upper and lower sides. , upper and lower guide covers each having opposing surfaces formed in a cross-sectional shape corresponding to the inner and outer shapes of the side seam and its surrounding area are arranged oppositely across an inert gas induction gap, and face the feed line of the upper and lower guide covers. A manufacturing device for a gold-layered container in which a group of inert gas outlets are arranged in a straight line along both sides. 21 The film thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400λ or less, and the oxide film is downwardly aligned along the upper side of the feed line of the side seam over a predetermined section immediately after the side seam passes between the upper and lower electrode rollers. In the evening, a group of inert gas blowing holes are arranged downward at equal intervals on both sides of the group of inert gas blowing nozzles and at the end of the predetermined section, and the gas curtain ejected from the group of blowing holes is used to blow out the inert gas. A manufacturing device for a metal container that continuously surrounds an atmosphere of inert gas blown out from a group of gas blowing nozzles to shut it off from outside air. 22 The film thickness of the oxide film generated on the electric resistance welding surface can be suppressed to at least 400 Å or less, and from immediately after the side seam passes between the upper and lower electrode rollers, over a predetermined section, the feed line of the side seam is sandwiched between the upper and lower electrode rollers. A group of upper and lower inert gas blow-off holes is arranged facing each other at equal intervals on both sides of the group of inert gas blow-off nozzles arranged oppositely and across the terminal end of the predetermined section, and a gas curtain ejected from the group of blow-off holes is used to control the inert gas blow-off nozzle. A manufacturing device for a metal container that continuously surrounds an atmosphere of inert gas blown out from a group and shuts it off from the outside air.