JPH05152B2 - - Google Patents

Description

[Detailed description of the invention]

[Prior art] Can materials such as tinplate are molded into a cylindrical shape, and the joints on both edges are joined to lap seams, lock seams, or a combination of these seams using solder, adhesive, etc., and cans are manufactured. Can be done.
However, this can manufacturing method requires a considerable area for the joint, which poses problems in terms of resource conservation, and also requires adhesive cans (cans joined with adhesive).
In this case, there are problems with the strength and durability of the seam. Furthermore, solder cans (cans joined by solder) and adhesive cans have a considerable level difference in the joined joint, so when double-sealing with the can lid,
There is a problem in that leakage is likely to occur at stepped portions. Conventionally, seamless cans (seamless cans) made by drawing and ironing have been used as cans in place of solder cans in some fields. In other words, it is completely impossible to use it in cans whose contents are sterilized by retort. Other examples of cans made using a can manufacturing method that replace solder cans include:
Welded seam cans are already known, in which both ends of a cylindrical can material are lap-joined by welding. In such welded seam cans, the area of the lap joint is significantly smaller than that of solder cans, etc., and the thickness of the joined joint is also relatively small, which alleviates the problems associated with the step mentioned above. , which has the advantage of not requiring a special bonding agent such as solder, but as will be explained later, depending on the type of can material, the manufacturing operation may be troublesome, and the bonded joint may be difficult to manufacture. The corrosion resistance, paint adhesion, and appearance characteristics of these materials were still not fully satisfactory. The above-mentioned welded seam cans are manufactured by overlapping the joints of both edges of can materials molded into a cylindrical shape, and passing the overlapping joints between a pair of upper and lower electrode rollers, or by passing an electrode wire between the overlapping joints between a pair of upper and lower electrode rollers. This is generally carried out by passing the joint between a pair of upper and lower electrode rollers via an electric resistance welding method. [Problem to be solved by the invention] By the way, among the materials for cans, electrolytic chromate-treated steel sheets (Tein Free Stale, hereinafter referred to as TFS) obtained by electrolytic chromate treatment of steel sheets are used.
Compared to other can materials such as tinplate, it has the advantage that it is inexpensive and easily available, and also has excellent corrosion resistance and paint adhesion. However, this TFS always has a chromium hydrated oxide layer with high electrical resistance on its outer surface, which inhibits current conduction when using current copper or copper matrix alloy electrode wires for electrical resistance welding. There is the problem of having to remove the chromate film containing the chromium hydrated oxide layer on the TFS iron surface prior to this welding operation. Therefore, the conventional manufacturing method of TFS welded cans (welded cans using TFS) has the problem of increasing the number of steps, and also has the problem that the chromate film at the joint is removed to expose the iron surface. However, there is a disadvantage that the corrosion resistance and paint adhesion of this part inevitably decrease. Furthermore, these chromate films are generally removed by mechanically polishing the joints where the TFS materials are to be overlapped, but during this polishing, debris and particles separated from the materials may cause other materials to be damaged. This results in damage to the chromate coating or paint on the part, and the incorporation of these fragments and particles into the contents of the can. In contrast, recently, TFS materials for non-polishing seam welding that do not require pre-treatment by polishing,
A non-polishing TFS welding method is being researched and considered. TFS materials for non-polishing seam welding include those made by thinning the chromium hydrated oxide layer of conventional TFS to reduce the electrical resistance between the chromate films at the overlapped joints, and those that reduce the electrical resistance between the chromate films at the overlapped joints, as well as those that reduce the electrical resistance between the chromate films at the overlapped joints. A method has been proposed in which the chromium hydrated oxide layer is destroyed during welding pressure by making the chromium layer contain finely divided particles, thereby reducing the electrical resistance between the chromate films. These methods aim to uniformly generate heat through resistance heating between overlapping chromate films, and suppress the occurrence of splash (a phenomenon in which molten iron protrudes outside the joint) at the weld joint interface, while also improving the weld joint area. Efforts are being made to improve airtightness and joint strength. However, even if such methods are used, the electrical resistance of the contact area between the TFS material and the electrode wire cannot be reduced.
The temperature of the inner and outer surfaces of the overlapped joints becomes high, causing splash, making it impossible to obtain a weldable current value, or even if it is obtained, it is limited to a very narrow range, making it difficult for industrial use. This method has problems that make it inapplicable to high-speed welding can manufacturing. On the other hand, unpolished
As a TFS welding method, there is a method in which the electrode wire is tinned to reduce the contact resistance between the electrode wire and the chromate film of the TFS material, thereby improving weldability. Since tin is a soft metal with a low melting point, it can reduce contact resistance with materials and enable welding. However, the solid lubricity of tin causes slippage when holding the material between a pair of electrode wires, making it difficult to stably overlap them with a constant width. moreover,
Electrode rollers and electrode wires are made of copper or copper alloy, so copper-tin alloy grows during welding, and long-term operation can contaminate the electrode rollers that hold the electrode wires, which can interfere with operations. Sometimes I give. On the other hand, if a commonly used tin-plated steel plate, i.e., can-making tin, is used as a material for cans, the aforementioned problem of blocking current flow does not occur, but the worldwide depletion of tin resources is a problem. It is an expensive metal, and reducing the amount of tin plating is being seriously considered in the field of can manufacturing. However, a decrease in the amount of tin plating not only inevitably leads to a decrease in the corrosion resistance of the can, but also causes a significant increase in the contact resistance between the material and the electrode roller or electrode wire during the production of welded cans, resulting in a weldable current value. is limited to a very narrow range. For this reason, if the current is insufficient, complete bonding cannot be achieved, and if the current is excessive, the temperature of the inner and outer surfaces of the overlapping joints will become high, causing splashes or the tin plating layer. Loss of protective effect due to fume scattering or acceleration of oxidation due to high temperature causes defects such as poor appearance of joints, decreased corrosion resistance, and poor paint adhesion. Therefore, an object of the present invention is to obtain a well-joined joint by electrical resistance seam welding of overlapping joints without removing the chromate film of electrolytically chromate-treated steel sheets used as can manufacturing materials. Furthermore, it can be applied to ultra-thin tin-plated steel sheets and nickel-plated steel sheets, which are recently being developed as materials for can manufacturing, by electrical resistance seam welding of overlapped joints, and similarly well-joined joints. It is an object of the present invention to provide an electric resistance seam welding electrode wire for can making, which can be obtained. [Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted repeated research on welding characteristics in electric resistance seam welding, with particular emphasis on heat generation characteristics. As a result, welding characteristics not only greatly depend on the surface characteristics of the can material such as TFS (electrolytic chromate treated steel sheet), but also the electrical interface between the surface of the electrode wire and the surface of the material that come into contact during welding. We found that it also depends greatly on electrical characteristics. In other words, the copper electrode wire and copper matrix alloy electrode wire used in electrical resistance seam welding are soft materials, so even when pressure is applied during welding, the chromium hydrated oxide layer remains on the top surface. The contact resistance at the interface with the can material is originally high. Since the surface of the electrode wire is likely to be covered with a very thin copper oxide film, the contact resistance at this interface becomes higher. In addition, electrode wires coated with tin on copper or copper matrix alloys can reduce the contact resistance at this interface, but due to the high solid lubricity of tin, the joints of the can material can be accurately bonded during welding. Because it is difficult to maintain a constant width, when resistance seam welding is performed at high speed, it is impossible to weld a constant width due to slippage. Therefore, the present inventors further investigated the electrode wire surface, the interfacial contact resistance between this surface and the can material surface,
After repeated research into the lubrication properties of the surface, we found that
If the surface of the copper or copper-based alloy electrode wire is coated with a film such as chromium, which has the effects of preventing surface oxidation, reducing contact resistance with the can material, and preventing slippage with the can material, the above-mentioned effect can be achieved. I found that I could achieve my goal. This invention was made based on the above findings, and the electrode wire of this invention has surface oxidation prevention on the surface of the electrode wire made of copper or copper matrix alloy.
It is characterized by the formation of a plating layer made of a plating metal such as chromium, which has various effects of reducing contact resistance with the can material and preventing slipping between the can material and the can material. In this invention, the copper or copper-based alloy electrode wire that forms the plating layer is a known copper or copper-based alloy electrode wire with a diameter of about 1.5 mm that is used in electrical resistance seam welding for can manufacturing. say. In addition to chromium, nickel and iron can be used as the plating metal that has the above-mentioned effects to be used in the present invention. These chromium, nickel, and iron may be used alone to form a plating layer on the surface of an electrode wire made of copper or a copper matrix alloy, or two or more of them may be combined to form a plating layer in the form of an alloy. Furthermore, chromium can also form a plating layer in the form of hydrated or non-hydrated chromium oxide.
Furthermore, the plating layer can be formed with a metal chromium layer as the lower layer and a thin chromium oxide layer as the upper layer. The plating layer made of metallic chromium and the plating layer consisting of the metallic chromium layer and a thin chromium oxide layer thereon can also contain particulate metallic chromium. These plating layers are made of chromium, which is the plating metal,
Due to the properties of nickel, iron, and chromium oxides, they all have excellent corrosion resistance and surface oxidation prevention properties, preventing surface oxidation of electrode wires during storage and use. In addition, these plating layers are
It itself has poor workability and is easily destroyed during welding pressure, exposing the new surface of the underlying copper of the electrode wire. At the same time, it destroys the chromium hydrated oxide layer of the film on the outermost surface of the can material. Therefore, although the chromium hydrated oxide layer itself has a high contact electrical resistance, it is possible to significantly reduce the contact electrical resistance at the interface between the electrode wire and the welded portion of the can material during welding. In particular, when the plating layer is made of or has a metallic chromium layer, the hard metallic chromium promotes the destruction of the chromium hydrated oxide film, so that extremely low interfacial contact resistance can be achieved. When the metallic chromium layer contains particulate metallic chromium, the contact resistance at the interface becomes even lower because film breakage is further promoted. moreover,
The large surface friction of the plating layer prevents slippage between the electrode wire and the can material, making it possible to maintain the joint with an accurate overlapping width. For this reason, even if the material for the can is TFS, etc., the chromate film etc. on the surface can be removed without removing it.
It becomes possible to perform good welding. In the case of a plating layer made of metallic chromium, or a plating layer consisting of a metallic chromium layer and a thin chromium oxide layer thereon, the plating layer is applied to the surface of an electrode wire made of copper or a copper matrix alloy from 0.005 to 0.05% in terms of chromium.
It is preferable to form with a plating amount of 1 g/m ² .
If the amount of plating is less than 0.005 g/m ² , the desired effect of the present invention cannot be sufficiently achieved. In order to obtain a more stable effect, the amount is preferably 0.01 g/m ² or more. On the other hand, even if the amount of plating exceeds 1 g/m ² , there is no corresponding improvement in the effect and it is only disadvantageous in terms of cost. In the case of a plating layer made of chromium oxide, 0.005 chromium equivalent is applied to the surface of the electrode wire.
It is preferable to form with a plating amount of ~0.1 g/m ² . If the amount of plating is less than 0.005 g/m ² , the desired effect of the present invention cannot be obtained sufficiently, as described above, and on the other hand, if the amount exceeds 0.1 g/m ² , there is no corresponding improvement in the effect and the cost is reduced. be at a disadvantage. In order to obtain a more stable effect, the amount should be 0.01 g/m ² or more. Nickel, iron, nickel - iron alloy, nickel -
In the case of a plating layer made of any one of chromium alloy, iron-chromium alloy, or nickel-iron-chromium alloy, it is preferably formed on the surface of the electrode wire with a thickness of 0.01 to 2.0 μm. Thickness is 0.01μm
If the amount is less than that, the desired effect of the present invention cannot be sufficiently obtained. For more stable effect, 0.02μ
m or more is preferable. On the other hand, even if the thickness exceeds 2.0 μm, there is no corresponding improvement in the effect, which is disadvantageous in terms of cost. To form the above-mentioned plating layer on the surface of an electrode wire made of copper or a copper matrix alloy, it is possible to use a known electroplating method that is commonly used in the production of surface-treated steel sheets such as tin plate and TFS. good. Furthermore, this does not include, but is not limited to, immersion chemical plating,
It is also possible by vapor deposition plating. Can materials to which electrical resistance seam welding using the electrode wire of this invention is applied include electrolytic chromate treated steel sheets (TFS), granulated electrolytic chromate treated steel sheets (granulated TFS), ultra-thin tin-plated steel sheets, and ultra-thin nickel-plated steel sheets. A steel plate is raised. TFS is
For example, it is a surface-treated steel sheet having an electrolytic chromate film consisting of a metallic chromium layer of 100 mg/m ² and a chromium hydrated oxide layer of 10 mg/m ² in terms of chromium thereon. Granulated TFS is a surface-treated steel sheet in which the metal chromium layer in the electrolytic chromate film is entirely granulated. Ultra-thin tin-plated steel plate, for example, 500
mg/m ² tin plating layer and 7 mg/m ² on the tin plating layer
of metallic chromium and its chromium equivalent: 12mg/
This is a surface-treated steel sheet having a chemically treated film consisting of chromium hydrated oxide of ^m2 . The ultra-thin nickel-plated steel sheet has, for example, a nickel-plated layer of 500 mg/ ^m2 ,
This is a surface-treated steel sheet having 4 mg/m ² of metallic chromium on the nickel plating layer and a chemically treated film consisting of 6 mg/m ² of chromium hydrated oxide in terms of chromium. In order to perform electric resistance seam welding of the overlapped joints of these can materials bent into can shapes using the electrode wire of the present invention, as shown in FIG. This can be done using a welding machine. That is, the joined portion 1a of the overlapping can materials 1 is gripped by the upper and lower conductive rolls 3a, 3b of the welding machine via the electrode wire 2. Then, by rotating the upper and lower conductive rolls 3a and 3b,
While moving the stacked joint 1a and the electrode wires 2 above and below it together in the horizontal direction, electricity is applied to the stacked joint 1a from the upper and lower conductive rolls 3a, 3b through the upper and lower electrode wires 2, Thereby, the joint parts 1a may be heated by electrical resistance, and the joint parts 1a may be welded together. As mentioned above, with the electrode wire of this invention, even if the material for the can is TFS etc., it can be bonded well without removing the chromate film etc. on the surface. Furthermore, since the plated metal is also inexpensive and requires less plating, it has the advantage of being able to significantly reduce the price. In addition, since the amount of plating is small, the amount of impurities mixed into the electrode wire is significantly smaller than that of tin-plated electrode wire, so it is extremely difficult to recover copper from discarded electrode wire after use. It is a flight. Furthermore, when the impurities mixed in are mainly chromium, it is also possible to regenerate the electrode wire as a general-purpose copper-chromium alloy electrode. [Example] Examples of the present invention will be described below. Example 1 A pure copper wire with a circular cross section of 1.38 mm in diameter was subjected to continuous cathode electrolysis in an aqueous dichromic acid solution to produce a plating layer consisting of chromium oxide of 0.02 g/m ² in terms of chromium on the surface of the pure copper wire. I made electrical resistance seam welding electrode wire for cans. Using this electrode wire, we seam welded the joint of the body of the food can with a Sudronik type welding machine (welding current 500Hz), and with another Sudronik type welding machine (welding current 175Hz).
Seam welding of the body joint of a 5 gallon can was performed. Then, the weldability at that time was investigated. Both beverage cans and 5-gallon cans are made of ultra-thin tin-plated steel sheets.
Four types were tested: TFS, granulated TFS, and ultra-thin nickel plated steel sheet. Example 2 Pure copper wire similar to Example 1 was subjected to continuous cathode electrolysis in an aqueous solution mainly containing chromic anhydride to form a 0.1 g/m ² metallic chromium layer on the surface of the pure copper wire and a chromium equivalent layer on the surface of the pure copper wire. An electric resistance seam welding electrode wire for can making having a plating layer consisting of a chromium hydrated oxide layer of 0.005 g/m ² was prepared. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Example 3 Pure copper wire similar to Example 1 was plated with metallic chromium by continuous vapor deposition in a vacuum to produce a can manufacturing product having a plating layer consisting of a 0.07 g/m ² metallic chromium layer on the surface of the pure copper wire. I made electrical resistance seam welding electrode wire. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Example 4 A pure copper wire similar to Example 1 was used as an intermittent cathode electrode in an aqueous solution mainly containing chromic anhydride, with weak anodic electrolysis inserted in the middle.
A 0.1g/ ^m2 metallic chromium layer with granular metallic chromium on the entire surface and a chromium equivalent of 0.005g/m2 on top.
A plating layer consisting of a m ² chromium hydrated oxide layer,
An electric resistance seam welding electrode wire for can making having a pure copper wire surface was made. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was examined. Example 5 Pure copper wire similar to Example 1 was subjected to continuous cathode electrolysis in an acidic aqueous solution mainly composed of nickel sulfate to produce a can-making electric wire having a plating layer consisting of a 0.1 μm metal nickel layer on the surface of the pure copper wire. I made resistance seam welding electrode wire. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Example 6 Pure copper wire similar to Example 1 was subjected to continuous cathodic electrolysis in an acidic aqueous solution mainly composed of nickel sulfate and ferrous sulfate to form a 0.1 μm nickel-iron electrodeposited alloy layer on the surface of the pure copper wire. An electric resistance seam welding electrode wire for can manufacturing with a plating layer was made. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Example 7 The same pure copper wire as in Example 1 was subjected to continuous cathode electrolysis in an acidic aqueous solution mainly composed of nickel chloride and chromium chloride to form a plating layer consisting of a 0.2 μm nickel-chromium electrodeposited alloy layer on the surface of the pure copper wire. We made an electric resistance seam welding electrode wire for can manufacturing. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Comparative Example 1 The same pure copper wire as in Example 1 was used as an electrode wire without being plated. This is the current non-plated electrode wire. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was investigated. Comparative Example 2 Pure copper wire similar to Example 1 was tin-plated by hot-dip plating to produce electrical resistance seam welding for can manufacturing having a plating layer of tin and tin alloy with a thickness of 0.17 μm on the surface of the pure copper wire. An electrode wire was made, and welding was performed using this in the same manner as in Example 1, and weldability was investigated. Comparative Example 3 The same pure copper wire as in Example 1 was tin-plated by continuous electroplating to produce an electric resistance seam welding electrode wire for can making, which had a plating layer of tin with a thickness of 0.1 μm on the surface of the pure copper wire. I made it. Using this electrode wire, welding was performed in the same manner as in Example 1, and weldability was examined. The results of the weldability investigation in Examples 1 to 7 and Comparative Examples 1 to 3 are shown in Tables 1 to 4.

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〔Effect of the invention〕

According to the electrode wire of the present invention, it is possible to satisfactorily join the overlapped joint portions without removing the chromate film of the electrolytically chromate-treated steel sheets used as the raw material for cans, and it is also possible to bond the overlapping joints well, and also to bond the overlapping joints of the can materials such as ultra-thin tin-plated steel sheets and ultra-thin nickel-plated steel sheets. It can also be applied to steel plates to satisfactorily join overlapping joints.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing electrical resistance seam welding of overlapping joints of can materials using an electrode wire using a Sudronik type welding machine. In the drawings, 1... Can material, 1a... Joint portion, 2... Electrode wire, 3a, 3b... Conductive roll.

Claims (1)

[Claims] 1. On the surface of a copper or copper matrix alloy electrode wire,
The plating layer made of metallic chromium is converted into chromium.
An electric resistance seam welding electrode wire for can making, characterized in that it has a formation of 0.005 to 1 g/m ² . 2. The electric resistance seam welding electrode wire for can manufacturing according to claim 1, wherein the plating layer contains granular metallic chromium. 3. On the surface of the copper or copper matrix alloy electrode wire,
The plating layer made of chromium oxide is 0.005 to 0.1
An electric resistance seam welding electrode wire for can manufacturing, characterized by forming a g/ ^m2 . 4. On the surface of the copper or copper matrix alloy electrode wire,
A plating layer consisting of a metallic chromium layer and a thin chromium oxide layer on top of the metal chromium layer is applied at a rate of 0.005 to 1 g/chromium equivalent.
An electric resistance seam welding electrode wire for can manufacturing, characterized by forming ^m2 . 5. The electrical resistance seam welding electrode wire for can manufacturing according to claim 4, wherein the metallic chromium layer contains granular metallic chromium. 6. On the surface of copper or copper matrix alloy electric wire,
Nickel, iron, nickel-iron alloy, nickel-chromium alloy, iron-chromium alloy or nickel-iron-
A plating layer made of any one of chromium alloys,
An electric resistance seam welding electrode wire for can making, characterized in that it is formed with a thickness of 0.01 to 2.0 μm.