KR850001365B1 - Method of welding tin coating can - Google Patents

Abstract

No content.

Description

Manufacturing method of welding can

1 is a plan view showing a welding can of the present invention.

2 is an enlarged cross-sectional view of the raw material of the welding can of the present invention.

3 is an enlarged sectional view of a seam portion of the side surface of the welding can of FIG.

4 is an explanatory diagram showing a method for manufacturing a welding can of the present invention.

5 is a graph showing the concentration ratio of each element on the material surface before welding.

6 is a diagram showing the concentration of each element on the weld surface when welded in a non-oxidizing atmosphere using tin-plated copper wire.

FIG. 7 is a graph showing the concentration ratio of each element on the welding surface when welding in a non-oxidizing atmosphere using copper wire. FIG.

8 is a diagram showing the concentration ratio of each element on the welding surface when welding in the air using a copper wire.

9, 10, and 11 are photomicrographs showing the metallographic cross-sectional structure of a welded joint, showing the samples 4, 7 and 8 of FIG.

The present invention relates to a manufacturing method of a new welding can, and more specifically, metal or metal is formed of a surface-treated steel sheet having a tin-iron alloy layer and a chromium hydride oxide layer thereon, and such a coating layer is formed inside and outside the welded joint. The present invention relates to a method for producing a new welded tube, in which a welded joint is formed by retaining on the surface thereof, which is excellent in corrosion resistance and adhesion of paint and exhibits good appearance characteristics.

As a conventional manufacturing method, a can-making material such as a tin-plated steel sheet is formed in a cylindrical shape, and both ends thereof are joined using a lap seam, a oxy seam, or a combination seam thereof using a soldering agent or a lubricating agent. have. However, the manufacturing method requires a certain area in the seam, and there is a problem in terms of resource saving, and in the case of the can by the bonding means, there is a problem in terms of strength and durability of the joint. In addition, in the case of a seam can with solder and an adhesive, there is a level difference in the side seam to some extent, so that there is a problem that frequent leakage occurs at the stepped portion during double joint with the can lid.

Conventionally, a canning method instead of a soldering can has been used in certain fields of seamless (simless) cans by draw-ironing. Because of its size, it is hardly possible to use a vacuum can, ie, the contents as a can for retort use. As another example of the canning method replacing the soldering can, a welding can in which both ends of the can manufacturing are wrapped (polymerized) by welding is also known. Such welding cans have a significantly smaller area than the lap seam compared to solder cans, and the thickness of the seam is relatively thin, thus alleviating the problems caused by the above steps and eliminating the need for a special solder and a special bonding agent. However, depending on the type of can-making material, the manufacturing operation is inconvenient, and the corrosion resistance of the joint is not yet sufficiently satisfactory in the adhesiveness and appearance characteristics of each paint.

In the production of the welding seam can, the polymerization portion is formed by passing a polymerization portion formed by forming a can-making material into a cylindrical shape between a pair of upper and lower electrode rollers, or a pair of upper and lower electrode rollers through an electrode wire. It is generally performed by welding electric resistance.

Tin-fried steel obtained by treating a rolled steel sheet of can-making material with electrochromic acid is cheaper and more readily available than other can-making materials such as tin-coated steel sheets, and has excellent corrosion resistance and adhesion to paint. It has an advantage, but that tin. The free seal (hereinafter simply referred to as TFS) has a problem in that a high battery resistance chromium oxide layer exists on the outer surface thereof and inhibits the energization during the above electrical resistance welding, and prior to the welding operation, There is a hassle to remove the chromium coating layer of surface thread. Thus, the conventional manufacturing method of the TFS welding can has the drawback of increasing the number of processes, and at the same time, the corrosion resistance of the part and the adhesion of the paint are inevitably deteriorated by removing the chromium coating layer of the joint and exposing the iron surface. In addition, the removal of these chromium layers causes damage to the chromium coating layer and the paint of other parts of the material, and also causes the problem that these fragments and particles are frequently incorporated into the contents of canned food.

On the other hand, when the conventional tin-plated steel sheet, i.e., a manufactur key for canning, is used as a can manufacturing material, the above problem of interruption of electrical conduction does not occur, and tin is an expensive metal that is depleted in resources all over the world. Also in the field, the tin plating amount is seriously examined. However, decreasing the tin plating amount inevitably lowers the corrosion resistance of the can, and in the case of manufacturing a welding can, significantly increases the contact resistance between the material and the electrode or the electrode wire. When the temperature inside and outside the surface becomes high, a slash splash occurs (or molten iron is pushed out of the joint), or the loss of the protective effect by the scattering of fume in tin plating or oxidation promotion by high temperature. This results in defects such as poor appearance of the joint, deterioration in corrosion resistance, and poor adhesion of the coating layer.

An object of the present invention is to form a surface-treated steel sheet having a significantly thin tin plated layer and a chromium hydroxide oxide layer thereon as compared to the conventional tin-plated steel sheet for conventional canning, and the chromium hydrate layer of the surface-treated steel sheet It is to provide a novel method that enables direct electrical resistance welding without removing. Accordingly, the present invention relates to a method for manufacturing a welding can, which does not require removing the surface layer by mechanical polishing such as edge cleaning in advance.

According to the present invention, in the manufacturing method of a welding can, in which a raw material made of a surface-treated steel sheet is formed in a cylindrical shape and subjected to electric welding by passing a polymerized portion through a pair of electrode rollers through an electrode wire, the surface-treated steel sheet is a steel sheet substrate. An electrode wire having a coating amount of 0.05 to 1.0 g / m ² (metal chromium equivalent) formed thereon and having a plating layer having a thickness of 0.15 to 2.0 μm of tin or tin alloy formed on the surface of the surface-treated steel sheet. Provided is a method for manufacturing a welding can, wherein the welding can is carried out in an inert atmosphere by being in close contact.

In FIG. 1 showing the welding seam can of the present invention, the raw material 1 made of a specific surface-treated steel sheet is molded into a cylinder, and the edges 2 and 2 of both ends thereof are polymerized, and will be described in detail later. The side seam 3 is formed by joining by specific welding means.

In FIG. 2 in which the cross-sectional structure of the raw material 1 is enlarged and displayed, the raw material 1 is formed of a steel tin substrate 4 and a metal tin layer or tin iron alloy 5 formed on the steel substrate and the layer ( 5) composed of a chromium hydroxide oxide layer 6 formed thereon. It is important for the metal tin layer or the tin-iron alloy layer 5 to be expressed as metal tin to have a coating amount of 0.05 to 0.05 g / m ² . That is, when the coating amount of tin is larger than the above-mentioned range, the tin plating amount is lower than that of the conventional tin-coated steel sheet for steel making, and this does not meet the purpose of lowering the cost of the material, and the amount is smaller than the above-mentioned range. At this time, the contact resistance with the electrode wire becomes high, and the above-mentioned various problems arise, and it is especially unsuitable for a high speed welding pipe. On the other hand, the chromium hydroxide 6 is closely related to the adhesion of paints and the like, and when it is less than the above-mentioned coating amount, there is a tendency for poor adhesion of the coating film. This leads to problems as described above. In addition, when the tin coating amount is small and when the chromium oxide layer has a large coating amount, the workability of the welding can, for example, the flange processing and the winding processing, may be poor.

The surface-treated steel sheet is degreased and pickled by a conventional method as described in, for example, Japanese Patent Laid-Open Publication No. 53-23833, 53-26236, and the amount of tin coated is It is produced by tin plating by electrolysis so as to be in a range, and by performing chromic acid treatment by electrolysis so that the chromium coating amount is in the above-described range after washing with water. The tin-plated side is mostly converted to a tin-iron alloy layer by heating (reflowing) as needed.A tin-plating bath is a known tin-plating bath, and an acidic tin such as tin sulfate or tin chloride is used. Any bath, or an alkaline tin bath such as a soda bath, a tartaric acid bath, etc. The electrochromic acid treatment is, for example, chromic anhydride in one type of production of sulfuric acid, a fluorine compound, an aromatic, disulfonic acid, riourea, and the like. It is carried out by cathodic electrolytic treatment with an electric quantity of 5 to 20 coulombs / dm ² using the bath to which the above is added, of course, the surface-treated steel sheet used in the present invention is not limited to the above-mentioned manufacturing method, but the above-described coating structure Any of those can be used as long as they have.

An important feature of the welding can of the present invention is that the canned material is used with the surface-treated steel sheet described in detail above, and the thickness of the oxide layer is regulated to 400 kPa or less on both outer surface portions of the side seam by welding. Both outer surface portions are in a combination on the premise that they have a tin coating amount of 60% or more of the tin coating amount of the original surface-treated steel sheet.

In general, in the case of performing a known electrical resistance welding of a cast iron plated steel sheet, the molten tin plating layer transfers to the electrode member or scatters as a fume, so that the protective effect of the tin plating layer is lost. On the surface, black or blue iron oxide (presumably Fe ₃ O ₄ ) is easily formed. Such a film of iron oxide generally reaches a thickness of 700 kPa to 3000 kPa, and the poor appearance of the joint causes defects such as deterioration of corrosion resistance and poor adhesion of the coating film.

In contrast, in the welding can of the present invention, tin, which is preferable in the oxidation prevention and corrosion resistance of iron, is retained at the outer surface portion of the seam at a high level of 60% or more of the tin coating amount of the original material, and further, the outer surface. As the oxide layer formed on the substrate is also suppressed to a remarkably light colorless level, the external appearance characteristics of the joint, the corrosion resistance and the adhesion of the paint are remarkably improved.

In the welding can according to the present invention, the oxide channel 8 is made of chromium oxide, formed of iron oxide and tin oxide, and the chromium oxide 9 is further distributed on the outer surface. Next to the oxide layer is a metal tin and tin-iron alloy layer. The transition from the oxide layer to the metal tin and tin-iron alloy layer may be either stepwise or continuous.

In FIG. 3, in which the outer surface portion of the side seam 3 is enlarged, the welding can of the present invention comprises an intermediate layer 7 made of iron-tin alloy and metal tin formed on a steel substrate 4 and an oxide layer thereon. (8) is provided.

In the present invention, the composition of the layer 7 mainly composed of the iron-tin alloy layer is not particularly limited, but it is likely to be in the range of 10: 1 to 1: 3 in the atomic ratio of Fe: Sn on average.

In FIG. 4 showing the manufacturing method of the present invention, in order to perform direct welding on the coated steel sheet, a plating layer of soft metal selected from the group consisting of tin and tin alloy as the electrode wires 10 and 10 '. It is important to use the electrode wire formed.

Conventionally, the use of electrode wires having a plating layer having a thickness of 30 to 300 μm of soft metals such as tin when welding plated steel sheets such as tin plated steel sheets with electrical resistance is known by Japanese Patent Publication No. 49-36860. . In contrast, according to the present invention, the thickness of the plated layers of the electrode wires 10 and 10 'is suppressed in a remarkably thin range of 0.15 to 2 占 퐉, whereby the thickness of the tin plated layer is extremely thin and high electrical resistance thereon. Seam welding is also possible for the material having the chromium oxide coating layer, and furthermore, the welding point is also successful in forming a uniform and strong seam. However, when the thickness of the electrode wire plating layer is thicker than 2.0 μm, sliding occurs between the wire and the material to be welded during welding, resulting in uniform welding points and inadequate seam strength or appearance. In addition, when the thickness of the plating layer is thinner than 0.15 mu m, the effect of tin plating is not seen, the amount of remaining tin on the surface of the material is markedly reduced, and the iron exposure area can be increased. That is, in the above known method, the resistance value between both is reduced by interposing a relatively thick plating layer between the material to be welded and the electrode wire. However, in the present invention, the thickness of the plating layer on the electrode wire is thinly opposed to the conventional idea. It has been found that the tin plating layer is only effective for welding a material on which an extremely thin and high electrical resistance chromium oxide layer is formed thereon. In the case of seam-welding the opposite polymerized portion, it is better to keep the temperature of both outer surface portions as low as possible compared to the temperature of the central portion of the polymerized portion to form a welded joint having excellent corrosion resistance, paint adhesion and appearance characteristics. Importantly, by using the electrode wires 10 and 10 'provided with the above-described plating layers of a specific thickness, it is possible to form a desirable temperature distribution in the polymerization portion as described above.

Thus, when the plating layer of the electrode wire is thicker than the above-mentioned range, the temperature of the inner and outer surface portions of the polymerized portion becomes excessively high, resulting in defects in the above characteristics. The slip is likely to occur, so it seems to be the cause here. Moreover, when the thickness of the plating layer is smaller than the above range, the amount of tin remaining on the surface of the raw material is considerably reduced, and the iron exposed area tends to increase.

As the electrode wires 10 and 10 ', those having the above-described plating layer formed on the copper wire substrate are used, and those having a flat cross section and having a cross section of 0.2 to 4 mm are suitable.

Conducting electrical resistance welding in a non-oxidizing atmosphere is important for the purpose of suppressing the thickness of the oxide layer to 400 kPa or less and maintaining the tin coating at a high level. Here, as an inert atmosphere, nitrogen, argon, neon, helium , Hydrogen and carbon monoxide can be used. Although the welding operation is preferably carried out by maintaining the welding joint in the air flow of the inert gas, the operation may be performed in a sealed container filled with the gas. In addition, in order to suppress the thickness of the oxide filler in the above-mentioned range, it is preferable to make the atmosphere until the surface temperature of a weld part falls to 550 degreeC as non-oxidizing atmosphere.

Here, the thickness of the surface oxide film was measured according to the atomic concentration ratio using ESCA and etching the surface with gas. When the welded part of the can that was welded in the non-oxidizing atmosphere was etched at a rate of 15 kW / min, the oxygen concentration was the largest on the surface and gradually decreased with etching, and within about 20-30 minutes. It becomes a fixed amount and is considered to be 400 Pa or less as a surface-surface oxide film thickness (refer FIG. 6).

The application pressure of the polymerization portion through the electrode wire is in the range of 20 to 90 kg / welding point, and is applied by the electrode rollers 11 and 11 'as a power source for electric resistance welding. A power source can be used, and the voltage and current may be conventionally used in the manufacture of a welding can.

The welding can according to the present invention has a high level of preferable tin in terms of corrosion resistance on the outer surface of the joint, and the oxide layer formed is also regulated to a very thin thickness, so that the corrosion resistance of the joint and the adhesion of the paint and It has a remarkable advantage that it is extremely excellent in terms of appearance and can be provided at low cost by using a material having a small tin plating amount.

The present invention will be described below with an example.

Example 1

Tin plating amount is 0.30g / m ^{2 with a} metal chromium conversion plate thickness of 0.24mm, hardness T ₄ of the welding material is used, the plating thickness of 0.5μ on the intermediate electrode 10, 10 'of FIG. A tin-plated copper wire was used to weld welds in the N ₂ gas stream under the following welding conditions.

Welding condition

Welding speed 30m / min Overlap amount 0.4mm

50kg electrode pressure

Comparative Example 1

Welding was carried out using copper wire to the intermediate electrode under the same material and the same welding conditions as in the example.

Comparative Example 2

The same materials as in Example 1 were welded using the same copper wire as the intermediate electrode in the atmosphere and without using the N ₂ gas stream.

The results are shown in Table 1 and FIGS. 5 to 8.

[Welding Range]

The welding current value when molten iron protrudes out of the welding part at the time of welding is applied as the upper limit, and the welding current value when peeling phenomenon occurs at the welding joint by applying external force such as peeling off the welding part of the welding part as the lower limit. The upper limit and the lower limit of the current value were set in the weldable range. The wider the weldable range, the easier the welding.

[Measurement of Relative Area]

A buffer of pH (10) containing 0.2 moles of sodium carbonate and 0.2 moles of sodium bicarbonate was filled into the can, and the anode was placed on the can and the cathode was grafted to measure the oxidation current of iron to determine the exposed area of iron. I used a method of finding relative values.

The oxidation current of iron and the iron exposure area are almost proportional. The voltage of the constant voltage device used for such a measurement uses the electric potential range which can almost ignore the oxidation current of Sn and Cr. The area of the measured data was cut out by 50 mm in length and 10 mm in width in the welding direction.

[Investment Test]

Sprayed 5% saline at 37 ℃ for 30 minutes to see the appearance of the eye. As for Ox of Table 1, two types were compared, and the one with a larger degree was made into x, and the one with less was marked with O.

The Fe, Sn, Cr, and O amounts on the weld surface shown in FIGS. 5 to 8 were measured by using an ESCA-Electron Spectroscopy for Chemical Analysis- (X-ray Photoelectron Spectroscopy) and etching the surface with Ar gas to the element concentration ratio. Measured by. The etching rate in this case is Fe: 15Å / min, Sn: had a 15Å / min: 8Å / min, Cr: 26Å / min O _2.

Example 2

The amount of tin plating is 0.30g / m ² with internal and external surfaces, the amount of chromium oxide is 5.0mg / m ² , the thickness of metal chromium conversion plate is 0.24mm, hardness T ₄ , and the amount of tin plating is 0.5g / with both internal and external surfaces. m ^2, chrome oxide settled amount 4.0mg / m ^2, in terms of metal chromium plate 0.24mm, the two types of welding materials of the hardness ② T ₄ and two kinds of air of the flat tin-plated copper wire of the flat donseon and plating thickness 1.5μ Welding was produced in the medium and N ₂ gas under the following welding conditions.

Welding condition

Welding speed 30m / min

50kg electrode pressure

TABLE 2

[Measurement of Steel Area Relative Value]

It is the same method as Example 1. However, the area of the data measured in Example 2 was cut out by 40 mm in length of a welding direction, and 3 mm in width, and measured.

)성이 우수함이 명백하다.In the results of Tables 1 and 2 and the results of figures 3, 4 and 5, the ease of welding, the iron exposure area of the welding surface and the antirust

It is clear that) is excellent.

Example 3

A welding can was produced in the same manner as in Example 1 except that a tin plated copper wire having a copper alloy layer thickness shown in the following table was used. The weldable range was measured in the same manner as in Example 1, and the results are shown in Table 3 below.

Moreover, the pitch of the weld part was observed, and the thing which is not equal to "O" at the equal interval was marked with "x". For some samples, the welded cross-sectional structure was taken with a micrograph and shown in FIG. 9 (electrode wire plating layer 0.50 m), FIG. 10 (electrode wire plating layer 3.00 m), and 11 (electrode wire plating layer 5.00 m). .

[Table 3]

From these results, it can be seen that by setting the thickness of the electrode wire to be 0.15 to 2.0 mu m, a wide weldable area can be ensured and the same welding can be performed at the same pitch. If the plating thickness exceeds 2,0 m, the welding pitch does not become constant due to sliding, and it is understood that the welding defect is caused at a large distance, resulting in poor sealing and insufficient bonding strength.

Claims (1)

In the manufacturing method of a welding can which is formed in a cylindrical shape of a surface-treated steel sheet and undergoes electrical resistance welding by passing a polymerized portion formed between a pair of electrode rollers through an electrode wire, the surface-treated steel sheet is coated on a steel plate substrate. A metal tin or tin iron alloy layer having an amount of 0.005 to 1.0 g / m ² (in terms of metal tin) and a chromium hydroxide oxide layer having a coating amount formed on the layer of 0.05 to 0.05 g / m ² (in terms of metal chromium), the surface of which is A method of manufacturing a welding can, characterized in that electrical resistance welding is performed in an inert atmosphere by bringing an electrode wire having a plating layer having a thickness of 0.15 to 2.0 μm of tin or tin alloy in close contact with a surface of a treated steel sheet.

Images