JPH0755382B2 - Electrode roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electrode roll used for electric resistance seam welding of superposed metal plates such as side seam portions of a can body, The present invention relates to an electrode roll in which a conductive liquid fusible alloy mainly containing gallium is enclosed in a void portion formed between a fixed portion and a rotating portion.

(Prior Art) In recent years, Suzuki steel plate, nickel plated steel plate nickel-
The overlapped part of the can body formed by rolling a metal plate such as a Suzuki steel plate into a cylindrical shape and stacking the edges on both ends is connected to the electrode roll inside the body using a copper wire electrode and the can body. BACKGROUND ART A can barrel is manufactured by an electric resistance seam welding method in which a molded body is clamped between the electrode roll and the electrode roll to be energized to perform welding.

A vertical sectional view of a typical electrode roll used in this electric resistance seam welding is shown in FIG.

In FIG. 4, 1 is an electrode roll, 2 is a fixed portion located at the center of the electrode roll 1 and having a disk-shaped portion 3,
Reference numeral 4 denotes a rotary portion that surrounds the disk-shaped portion 3 of the fixed portion and is rotatably attached to the fixed portion 2 (2 in the figure).
Shown is a combination of parts).

A groove portion 5 for accommodating a copper wire electrode is provided on the outer peripheral portion of the rotating portion 4, and a gap portion 6 is provided between the rotating portion 4 and the fixed portion 2.
Is formed, and the void 6 is filled with the conductive liquid metal 7.

Reference numeral 8 is a sealing material for preventing the conductive liquid metal 7 from leaking to the outside, and 9 is a ball bearing for facilitating rotation of the rotating portion 4 around the fixed portion 2.

Reference numeral 10 denotes a cooling liquid passage for passing a cooling liquid for preventing the electrode roll from becoming too high in temperature due to welding heat, and extends to the disk-shaped portion 3 of the fixed portion.

A current is introduced into the fixed part 2 through an electrode roll holder (not shown), and from the viewpoint of conductivity, most of the fixed part 2 and the rotating part 4 are made of copper or a copper alloy. The stationary portion 2 and the rotating portion 4 of the portion facing the cavity 6, in particular.
Is made of copper or a copper alloy.

As the electrode roll, in addition to the type shown in FIG.
A type in which the rotating part is rotatably mounted in the center of the fixed part, and a type in which the fixing part is arranged inside and outside the rotating part as disclosed in US Pat. No. 4051343. There is one.

In any type of electrode roll, a conductive liquid metal is interposed between the stationary part and the rotating part, which are mostly made of copper or a copper alloy, as a means for energizing them. Is common.

Mercury has conventionally been used as a conductive liquid metal for electrode rolls.

The reason is that the melting point of mercury is as low as −39 ° C., the liquid state is maintained at room temperature as well as at a considerably low temperature, and the conductivity is relatively good.

However, since mercury has a considerably high toxicity, a substitute for mercury is desired in consideration of leakage.

As an alternative to this mercury, the applicant has already disclosed in Japanese Patent Laid-Open No. 56-
62680 discloses a binary alloy of Ga87-73 wt% and In13-27 wt%, and Japanese Patent Laid-Open No. 57-75291 discloses Ga95 wt% and Sn5 wt%.
In addition, in JP-A-56-77076, a four-element alloy composed of gallium, indium, tin and zinc was proposed.

According to the findings of the applicant's research, even among four-element alloys, those having a Ga67%, In20%, Sn10%, and Zn3% by weight have a freezing point of 6.
It has 5 ℃, melting point of 8.5 ℃, electric resistance of 22μΩ ・ cm, and is more than 4 times more conductive than mercury's electric resistance of 95.8μΩ ・ cm.

In addition to this, Japanese Patent Publication No. 55-40355 discloses Ga69.5 ± 5.0, I
n15.2 ± 1.0, Sn6.1 ± 1.0, Zn4.5 ± 0.8, Ag3.2 ± 0.5, Al1.5
It is proposed to use ± 0.5 (atomic%) 6-element alloy to which 0.005 to 0.05% by weight of fine powder of impurities (SiO ₂ , Al ₂ O ₃ ) is added.

Further, in Japanese Patent Publication No. 55-40359, in an electrode roll using the above-mentioned 6-element alloy as a conductive liquid metal, the contact electric resistance between the 6-element alloy and the rotating part and between the 6-element alloy and the fixed part. In order to reduce the amount of noise, it has been proposed to apply a nickel plating or an iron plating to the rotating portion and the fixed portion facing the void portion (see 7 in FIG. 5).

In addition, the applicant, in Japanese Patent Laid-Open No. 57-75291, enables long-term use of an electrode roll in which a gallium element or a fusible alloy mainly composed of gallium is sealed as a conductive liquid metal with an inert gas in a space. In order to achieve the above, the melting point of the alloy formed when mixed during easy fusion mainly consists of the original gallium on the surface of the fixed part and the rotating part which face the void for accommodating the easy fusion metal. It has been proposed that the metal plating should be below the melting point of the easy fusion metal.

(Problems to be solved) As described above, most of the electrode roll is manufactured from copper or a copper alloy from the viewpoint of improving conductivity, but gallium has a strong corrosiveness to copper. Therefore, in the case of using the fusible alloy mainly containing gallium as the conductive liquid metal, after using the electrode roll,
Before a long time elapses, copper is mixed into the easy-melting alloy mainly composed of gallium from the fixed part and the rotating part to raise the melting point of the easy-melting alloy, so that the easy-melting alloy solidifies and rotates. There is a drawback that the parts cannot be rotated.

That is, the melting point of gallium alone is 29.8 ° C., whereas when 1% by weight of copper is mixed in gallium, the melting point of this alloy reaches 100 ° C.

For example, when a four-element alloy consisting of the above-mentioned weight ratios of Ga, In, Sn, Zn is used as the conductive liquid metal of the electrode roll, when 4% by weight or more of copper is mixed in this liquid metal. , The liquid metal gelled, and the rotating part stood unrotatable.

A concrete example of this state is as follows.

Conventional Example 1 Using the electrode roll having the structure shown in FIG. 4, as the conductive liquid metal 7, by weight ratio, Ga67%, In20%, Sn10%,
A 4-element alloy containing 3% Zn was used.

In the electrode roll 1, the fixed portion 2 is made of a chrome copper alloy and the rotating portion 4 is made of a beryllium copper alloy, and the conductive liquid metal filled and sealed in the void portion 6 directly contacts the surfaces of the chrome copper alloy and the beryllium copper alloy. It was in a state of contact.

This electrode roll 1 reached the point where 13 hours had passed after the start of its use for can body welding, and the rotating part 4 became unrotatable.

When the electrode roll 1 was disassembled and the surfaces of the chromium copper alloy and the beryllium copper alloy that were in contact with the conductive liquid metal 7 were examined, the entire surface was corroded.

The eroded state was almost the same in both the fixed part 2 and the rotating part 4.

Conventional Example 2 An electrode roll having the same structure as that of Conventional Example 1 is used, and the fixed portion 2 and the rotating portion 4 (that is, the rotating portion 4) of the surface in contact with the conductive liquid metal 7 in the space 6 between the fixed portion 2 and the rotating portion 4 (that is, , The outer surface of the fixed portion 2 facing the void portion 6 and the inner surface of the rotating portion 4) were coated with an average of 3 μm of cobalt, and the void portion 6 was filled with the same four-element alloy as in Conventional Example 1 and sealed (just. (The state is as shown in FIG. 1).

When this electrode roll 1 was used for can body welding,
After 93 hours, slippage occurred between the copper wire electrode and the electrode roll 1 due to the increase in the rotating torque of the electrode roll 1, so the use was stopped, and the electrode roll 1 was disassembled and inspected. The surface of the cobalt plating that was in contact with the liquid metal 7 was partially eroded and perforated, and the chromium copper alloy was also intensively perforated and eroded at that portion.

Further, the cobalt plating of Conventional Example 2 was replaced with a nickel plating, the four-element alloy was replaced with a two-element alloy consisting of 95% by weight of gallium and 5% by weight of tin, and the can copper was welded with nitrogen gas sealed in the void. However, at first, the welding was performed well, but after 10 hours, the electric resistance value gradually increased, and soon the rotation of the rotating part became not smooth.

Further, the conductive liquid metal is gallium simple substance or easy fusion metal mainly composed of gallium, and silver, tin, zinc, etc. are plated on the surface of the fixed portion and the rotating portion facing the void of the electrode roll, Some electrode rolls were prepared by mixing the conductive liquid metal in a nitrogen gas atmosphere and filling the voids with fusible metal and nitrogen gas.The welding time of some electrode rolls exceeded 150 hours. It had a large variation in the service life and lacked reliability.

As described above, the known electrode roll using the fusible alloy mainly composed of gallium as the conductive liquid metal is unpractical because the usable time is too short and the reliability is low.

The present invention is intended to solve the problems of the prior art as described above.

That is, the object of the present invention is to prevent the erosion of the copper or copper alloy, which is the main constituent material of the fixed part and the rotating part of the electrode roll, by the fusible alloy mainly composed of gallium, and the fusible alloy mainly composed of gallium. An object of the present invention is to provide an electrode roll for electric resistance seam welding, which exhibits excellent characteristics as a conductive medium (conductive liquid metal) between a fixed part and a rotating part and can be used for a long time.

Another object of the present invention is to provide an electrode roll for electric resistance welding, which has a small contact electric resistance between the fixed part and the rotating part of the easy-to-melt alloy mainly composed of gallium and generates a small amount of heat due to energization. .

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention has a fixing portion at least a part of which is made of copper or a copper alloy, and the fixing portion is rotatably attached to the fixing portion, and at least a part of the fixing portion. A rotating portion made of copper or a copper alloy, an annular void portion formed between the rotating portion and the fixed portion, and an easy fusion metal mainly containing gallium as a conductive liquid metal in the void portion. In the encapsulated electric resistance seam welding electrode roll, the copper or copper alloy material portion of the fixed portion and the rotating portion facing the void portion has a weight ratio of cobalt and tungsten of 90:10 to 30. :
Coated with a cobalt-tungsten alloy layer in the range of 70,
Further, the cobalt-tungsten alloy layer is covered with a thin layer of one kind of metal selected from the group consisting of tin, silver, zinc, gallium, indium and aluminum or an alloy of two or more kinds of metals. did.

(Operation) In the present invention, the fusible alloy mainly composed of gallium enclosed in the space between the fixed part and the rotating part is directly connected to the copper (or copper alloy) material part of the fixed part and the rotating part. A thin layer of one type of alloy selected from tin, silver, zinc, gallium, indium, and aluminum or a thin layer of an alloy of two or more types of metals, which forms the outermost layer of these surfaces without contact Although they will come into contact with each other, since these metals have good wettability with the easy-fusion gold mainly composed of gallium,
The electric resistance of contact between the easy fusion metal and the fixed portion and the rotating portion is small, and accordingly, the amount of heat generated during resistance welding is small.
Moreover, since these metals are gallium itself or a metal that forms a eutectic alloy with gallium, and the layer of these metals or alloys is thin, even if they are mixed in the easy-fusion alloy mainly containing gallium, the easy-fusion alloy is formed. Without significantly increasing the melting point of (at most, melting point of gallium simple substance), and further, between these metal layers or alloy layers and the copper (or copper alloy) material portion,
The cobalt-tungsten alloy layer exists in the range of 90:10 to 30:70 in weight ratio of cobalt and tungsten,
Since this cobalt-tungsten alloy layer has the property of being less likely to be corroded by gallium, even if welding is performed for a long time, the fixed part and the rotating part are not easily corroded, and therefore copper is mixed in the fusible alloy. As a result, the fusible alloy can continue to exhibit excellent characteristics as a conductive liquid metal.

(Examples and Experimental Examples) Next, the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an electrode roll for welding showing one embodiment of the present invention, and most of it is the same as FIG.

In FIG. 1, 1 is an electrode roll, 2 is a fixing part located in the center of the electrode roll and having a disk-shaped part 3, and 4 is a part surrounding the disk-shaped part 3 of the fixing part and with respect to the fixing part 4. And a groove 5 for accommodating the wire electrode is provided on the outer peripheral portion of the rotary portion.

Most of the fixed portion 2 and the rotating portion 4 are preferably made of a copper alloy such as a chromium copper alloy or a beryllium alloy from the viewpoint of conductivity and strength.

Reference numeral 7 is an easy-fusion alloy mainly containing gallium as a conductive liquid metal enclosed in a space 6 formed between the fixed portion 2 and the rotating portion 4, and is composed of the above-mentioned two-element alloy and four elements. In addition to alloys and 6-element alloys, various kinds of materials can be used, and some examples are Ga96.4%, Ag3.6% (all are weight%,
The same shall apply hereinafter), a two-element alloy consisting of Ga65.6%, In21.3%, Sn
4 element alloy consisting of 10.7%, Ag2.5%, Ga63.4%, In20.6
%, Sn10.3%, Zn3.3%, Ag2.4%, and other five-element alloys.

In addition, these elements are mixed and liquefied in an inert gas atmosphere.

Reference numeral 8 is a sealing material for preventing the easy fusion metal from leaking, and 9 is a ball bearing for facilitating the rotation of the rotating portion 4.

Further, 10 is a cooling liquid passage for passing a cooling liquid such as water, which extends to the disk-shaped portion 3.

An electric current is introduced into the fixed portion 2 via an electrode roll holder (not shown).

Reference numeral 11 is a metal coating layer that covers the fixed portion 2 and the rotating portion 4 in the portion facing the void portion 6. Referring to FIG. 2 which is an enlarged view of a main portion of FIG. 1, a copper alloy or The weight ratio of cobalt and tungsten coating the copper material surface is 90:10 to 30:
Cobalt-tungsten alloy layer 12 in the range of 70 and tin, silver coating on the cobalt-tungsten alloy layer 12;
It comprises a thin layer 13 of one metal selected from the group consisting of zinc, gallium, indium and aluminum, or an alloy of two or more metals.

The thickness of the cobalt-tungsten alloy layer 12 is 1 to 10 μm,
It is preferably 3 to 5 μm.

Further, the coating method of the cobalt-tungsten alloy layer 12 may be a well-known method such as an electric plating method and a thermal spraying method.However, when the electric plating method is adopted, from the viewpoint of the adhesion and adhesion of the alloy, It is desirable that the corner portions forming the convex portion and the concave portion of the fixed portion 2 and the rotating portion 4 to be covered be R = 0.4 mm or more to avoid an acute angle.

The thickness of the metal or alloy thin layer 13 on the cobalt-tungsten alloy layer 12 is not limited to this value, for example, 0.1.
It can be extremely thin, such as ~ 1.5 μm.

The upper limit of the thickness of the thin layer 13 depends on the kind and the amount of the fusible alloy mainly containing gallium used as the conductive liquid metal (the constituent metals and their mixing ratio) and the kind of the metal constituting the thin layer 13. Decided by

That is, even when all the metal forming the thin layer 13 is mixed in the easy-melting alloy mainly containing gallium, the melting point of the easy-melting alloy does not exceed the melting point of gallium (29.8 ° C.). To do.

The upper limit of the thickness of the thin layer 13 can be easily calculated by an experiment by measuring the surface areas of the fixed portion 2 and the rotating portion 4 to be covered.

Then, if the coating is performed with a thickness equal to or less than the calculated upper limit value, even if all of the metal of the thin layer 13 is mixed in the fusible alloy, the temperature during use of the electrode roll is sufficiently higher than the melting point of gallium. The fusible alloy can maintain its liquid state and continue to exhibit excellent characteristics as a conductive liquid metal.

This thin layer 13 is coated with a cobalt-tungsten alloy layer.
Similar to 12, various methods can be adopted.

The metal constituting the thin layer 13 can be any of those mentioned above. Among them, the price is low, the metal is easy to be plated, and the melting point of the fusible alloy when it is mixed with the fusible alloy mainly containing gallium. The tin is preferable from the viewpoint that the increase in the temperature is not rapid.

Further, FIG. 3 is a vertical sectional view of another embodiment.
The embodiment is exactly the same as the illustrated embodiment except for the rotating part.

That is, in the present embodiment, of the rotating part 4 composed of two parts 4a and 4b, the part 4a which faces the outer peripheral surface of the disk-shaped part 3 of the fixed part and through which a large current flows during welding is made of copper or copper alloy. The other component 4b is made of a material which is hard to be eroded by the easy fusion gold mainly composed of gallium, for example, nickel-chromium-iron alloy, chromium-iron alloy, cobalt-tungsten alloy, etc. Is.

Therefore, the cobalt-tungsten alloy layer is formed only on the portion of the rotating portion that faces the void portion 6 of the component 4a made of copper or copper alloy.
12 and a thin layer of a single metal or alloy selected from the group consisting of tin, silver, zinc, gallium, indium and aluminum 13
Is provided (see FIG. 2).

Since only a small current flows in the component 4b during welding, the welding performance does not significantly decrease without using copper or copper alloy.

Although not shown in the drawing, when a hole for filling the conductive liquid metal is provided in a part of the component 4b, there is no hole in the surface of the component 4a on which the cobalt-tungsten alloy layer 12 or the like is provided on the side of the void portion 6 side. Therefore, there is an advantage that it is easy to apply a uniform coating by an electric plating method or the like (there is a problem that a hole easily causes poor coating and is apt to be corroded).

Further, it is also preferable that the surface of the component 4b facing the void portion 6 is plated with tin, silver, zinc or the like directly or through another metal layer because the wettability with the easy fusion metal is improved.

In the present invention, the surface of the copper or copper alloy material portion of the fixed portion and the rotating portion facing the void is covered with a cobalt-tungsten alloy layer to form an easy fusion alloy mainly containing gallium. In order to utilize the excellent erosion resistance of the cobalt-tungsten alloy, it is known from the following experimental results that iron known to be used on the surface of the electrode roll that comes into contact with the easy-melting alloy mainly containing gallium. In comparison with nickel, tin, silver, and other metals, the cobalt-tungsten alloy has excellent erosion resistance with respect to the easy-melting alloy mainly containing gallium.

Experiment 1 Tin, zinc, silver, iron, nickel, cobalt thin plates (all have a thickness of 0.2 mm) and 2 mm thick copper plates with 4 μm Co-W
Prepared with a metal (Co: W = 40:60), each of which is a liquid 4-element alloy whose weight% is Ga67%, In20%, Sn10%, Zn3%, and a liquid 2 element consisting of Ga76%, In24%. Elemental alloy and Ga60.5%, In21.6%, Sn9.5%, Zn3.8%, Ag4.1
%, Al 0.5%, liquid 6 element alloy, 3
Drop one drop at a point, tin plate, zinc plate and silver plate 120 ℃
For 40 hours, the iron plate, nickel plate, cobalt plate, and Co-W plated copper plate are left at 300 ° C for 40 hours, and then placed in soapy water, water, and acetone in that order, Remove each alloy from each plate by applying a sound wave, observe each drip surface and measure the roughness of that surface, then cut the drip part and take a magnified photograph of its cross section Observe the condition,
In addition, the permeating metal was analyzed with an EGX measuring instrument.

The results are shown in Table 1 (drops of a four-element alloy), No. 2
The results are shown in Table (dropped with 2 element alloy) and Table 3 (dropped with 6 element alloy).

The roughness is the center line average roughness (μm), the upper part shows the roughness of the dropping surface, and the lower part () shows the roughness of the plate material base.

From the results of Table 1, Table 2 and Table 3, compared with metals such as iron, nickel, tin, silver, etc. which are known to be used for the surface of the electrode roll that is in contact with the easy-to-melt alloy mainly containing gallium. Then, it is found that the cobalt-tungsten alloy has a high erosion resistance with respect to the fusible alloy mainly containing gallium.

Next, in the present invention, of the fixed part and the rotating part facing the void, the weight ratio of cobalt to tungsten in the cobalt-tungsten alloy layer covering the surface of the copper or copper alloy material part is 90:10. The reason for limiting the range to 30:70 is that the alloys within this range are superior in erosion resistance to the fusible alloy mainly containing gallium, as compared with those outside the range.

This is clear from the following experimental results.

Experiment 2 In the electrode roll of the type shown in FIG. 1, the weight ratio of cobalt to tungsten was 95: 5,90: 10,80: 20,70: 30,60: 40,50: 50, 40: 60,30: 70,20:
Prepared by changing the value of 80 to a value of 3 μm in the fixed part and the rotating part facing the void, and mixing them in a nitrogen gas atmosphere. Ga67%, In20%, Sn10
%, Zn 3% (wt%), a four-element alloy was filled into the voids in air.

Three types of these electrode rolls were prepared, and welding can bodies were manufactured under the same conditions.

The results are shown in Table 4.

For the electrode rolls with a Co-W weight ratio of 95: 5, the rotation torque increased with a usage time of nearly 100 hours, and slippage was observed between the electrode rolls and the copper wire electrode, so the machine was stopped. Then, when the electrode roll was disassembled and the inside was inspected, it was found that in both cases, the perforations started at the fixed surfaces of the fixed part and the rotating part due to erosion.

In addition, the electrode rolls with a Co-W weight ratio of 80:20 to 30:70 all had no abnormal rotation torque even when the usage time exceeded 20 hours, but when disassembling and inspecting the inside, The easy fusion metal maintained the same fluidity as when it was filled, and neither the solid surface nor the rotating surface was eroded at all. However,
20-50% of the total surface area of the plated surface to which the fusible metal was not adhered (the same was true for the electrode roll having a Co-W weight ratio of 90:10). All of the electrode rolls having a Co-W weight ratio of 20:80 became unusable due to an increase in the rotating torque within 30 hours of use.

From this experimental result, the weight ratio of Co—W in the Co—W alloy layer is
It turns out that it is necessary to be within the range of 90:10 to 30:70.

Next, in the present invention, in order to improve the poor wettability of the cobalt-tungsten alloy layer with respect to easy-melting gold mainly composed of gallium, it is eroded by the easy-melting gold and mixed in the easy-melting gold. However, gallium itself selected from the group consisting of tin, silver, zinc, gallium, indium, and aluminum, or a metal forming a eutectic alloy with gallium, which does not significantly increase the melting point of the fusible alloy, or these 2 The cobalt-tungsten alloy layer is coated with a thin layer of an alloy composed of more than one kind of metal, and these metals have good wettability with respect to easy-melting gold mainly containing gallium. The result of Experiment 1 showing that the fusible alloy mainly containing gallium is easily eroded, and these metals are either a constituent of the fusible alloy or a gallium which is the main component of the fusible alloy. Although it is apparent from the fact that a metal to form an alloy, it is clear from the following comparative experiment.

Experiment 3 Prepare a copper plate with only 4 μm Co-W plating (co: W weight ratio of 40:60) and a plate with 0.4 μm tin plating on each of them, and prepare 5 flat plates each. After being placed in each case, the same four-element alloy used in Experiment 1 was dropped on the plate one drop at a time, and the lapse of time and the degree of spread of the four-element alloy were observed.

In the case of Co-W plating only, there is no change immediately after dropping and after 20 minutes have passed, whereas in the case of tin plating on Co-W plating, the four-element alloy spreads over time. I was tired.

The graph of FIG. 5 shows the relationship between time and the area obtained by calculating the average spread radius. According to this, the area increases almost linearly from just after the dropping until about 10 minutes later.

Therefore, when a coating layer of tin or the like that forms a eutectic alloy with gallium is provided on the surface of the Co-W alloy layer, the wettability with respect to easy-melting alloy mainly containing gallium is markedly higher than that of the Co-W alloy layer. It can be seen that it will be improved.

Example Nearly all of the fixed part 2 and the rotating part 4 were made of chromium copper alloy and beryllium copper alloy, and an electrode roll having a structure as shown in FIGS. 1 and 2 was manufactured.

The cobalt-tungsten alloy layer 12 that covers the fixed portion 2 facing the void 6 and the rotating portion 4 is an alloy having a weight ratio of cobalt and tungsten of 40:60 and a thickness of about 3 μm by the electroplating method. A thin metal layer 13 is formed by plating, and the thickness of the thin metal layer 13 is about 0.5 μm by the electric plating method.
It was painted with tin.

In addition, the conductive liquid metal 7 has a weight ratio of Ga67%, In20
%, Sn10%, Zn3%, a four-element alloy was used (mixing of the four-element alloy was performed in a nitrogen gas atmosphere), and the cavity 6 was filled and sealed in the atmosphere (the filling hole is (Not shown).

Using this electrode roll as an electrode roll for the inner surface of the can body, a welded can body made of # 25 tin plate material (plate thickness 0.22 mm) was manufactured under the following conditions (copper was used between each electrode roll and the tin plate material). Line electrodes were used).

Welding speed 50m / min Welder secondary current 4200A Electrode roll pressure 40kgf This electrode roll had no abnormality in the rotating torque of the rotating part even after 250 hours of welding.

After 250 hours of use, the electrode roll was disassembled and the inside was inspected. As a result, it was found that the fusible alloy mainly containing gallium was attached to the entire surface of the tin plating.

In the electrode roll of the present embodiment, since the fusible alloy mainly composed of gallium contacts the tin layer to erode the tin layer and adheres to the corroded portion at the same time, the fusible alloy is fixed between the fusible alloy and the fixed part and the rotating part. The contact electric resistance of is reduced, and along with this, the amount of heat generated at these interfaces during welding is suppressed, so that the corrosion of the fusible alloy with respect to the cobalt-tungsten alloy under the tin layer is also suppressed, Further, deterioration of the sealing material is suppressed.

Further, the contact electric resistance between the fusible alloy and the fixed part and the rotating part is much smaller than that in the case where only the cobalt-tungsten alloy layer is used as the coating layer, so that the conductivity is good and the quality of the welded part is stable. To do.

Furthermore, since a cobalt-tungsten alloy layer mainly composed of gallium and having a composition ratio that is not easily eroded by the fusible alloy exists below the tin layer, the fixed portion and the rotating portion that are protectively covered by this alloy layer. Even if the copper alloy of No. 3 is welded for a considerably long time, a situation in which the copper alloy is eroded by the fusible alloy and mixed into the fusible alloy does not occur.

As described above, the electrode roll of this example has a small contact electric resistance between the easy-to-melt alloy mainly composed of gallium and the fixed part and the rotating part, and further includes the tin layer existing on the contact surface with the easy-to-melt alloy. Even when tin is mixed in the fusible alloy, the fusible alloy continues to maintain a liquid state and excellent characteristics as a conductive liquid metal, and moreover, a cobalt-tungsten alloy layer is used to form copper. Since the alloy portion continues to be protected, it can be used for a long period of time without performing the operation of replacing the air in the void with an inert gas.

As the thickness of the metal that constitutes the thin layer of the metal or alloy coated on the cobalt-tungsten alloy layer, the wettability with the easy-to-use fusion alloy mainly composed of Galimuu is good, and the metal is the easy-to-use alloy. It is sufficient if the metal and its thickness (amount) are such that the melting point of this alloy does not exceed the melting point of gallium (29.8 ° C) when mixed into it to form a new alloy with a different mixing ratio. , Tin, silver, zinc, gallium,
A single layer of indium or aluminum or a thin layer of an alloy composed of two or more of these may be mentioned.

As the fusion alloy mainly composed of gallium, various alloys can be used as described above. Among them, the four-element alloy used in Example 1 has a considerably low melting point and is superior to the six-element alloy. It is particularly preferable because it has the advantages of easy preparation and low cost.

(Effect) In the present invention, of the fixed part and the rotating part facing the void,
The outermost layer of the coating layer that covers the surface of the copper or copper alloy material portion has good wettability with the easy-to-use fusion alloy mainly containing gallium enclosed in the void, and the easy-to-use fusion alloy. Since the thin layer is made of one kind of metal or an alloy of two or more kinds of metals, the melting point of which does not greatly increase even if mixed in the metal, the fusible alloy is brought into contact with the fixed part and the rotating part. Not only does it have a small electric resistance and a small amount of heat during welding, but it can also prevent solidification of the fusible alloy due to the mixing of the outermost layer metal, and furthermore, inside the outermost layer, cobalt and tungsten are in a weight ratio, Since a cobalt-tungsten alloy layer having a high corrosion resistance to the easy fusion alloy mainly containing gallium is provided in the range of 90:10 to 30:70, even if welding is performed for a long time. The copper of the fixed part and the rotating part is mixed in the easy fusion metal and Without solidifying the fusion money,
Therefore, the fusible alloy can continue to exhibit excellent characteristics as a conductive liquid metal.

That is, the electrode roll of the present invention uses the fusible alloy mainly containing gallium as a liquid metal, and uses copper or a copper alloy for at least a part of the fixed part and the rotating part facing the void for enclosing the gallium. However, there is an advantage that good electric resistance seam welding can be performed for a long time.

[Brief description of drawings]

1 is a longitudinal sectional view of an electrode roll according to one embodiment of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a vertical sectional view of an electrode roll according to another embodiment of the present invention, and FIG. 4 is a vertical sectional view of a conventional electrode roll. FIG. 5 is a graph showing the relationship between the area of the fusible alloy immediately after dropping the fusible alloy on the tin plating, the elapsed time thereafter, and the spread area. 1 ... Electrode roll, 2 ... Fixed part, 4 ... Rotating part, 6 ...
... Void portion, 7 ... Conductive liquid metal, 12 ... Cobalt-tungsten alloy layer, 13 ... One kind of metal selected from the group consisting of tin, silver, zinc, gallium, indium and aluminum, or two or more kinds A thin layer of metal alloy.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-62-45484 (JP, A) JP-A-61-293688 (JP, A) JP-A-57-75291 (JP, A) JP-A-56- 77076 (JP, A)

Claims (2)

[Claims] 1. A fixed part at least a part of which is made of copper or a copper alloy, a rotary part which is rotatably mounted on the fixed part and at least a part of which is made of copper or a copper alloy, and the rotary part. In an electrode roll for electric resistance seam welding, an annular void portion formed between the fixing portion and the fixing portion, and an easy fusion metal mainly containing gallium as a conductive liquid metal are enclosed in the void portion. The copper or copper alloy material portion of the fixed portion and the rotary portion facing the void is covered with a cobalt-tungsten alloy layer having a weight ratio of cobalt to tungsten within the range of 90:10 to 30:70. Further, the cobalt-tungsten alloy layer comprises tin, silver, zinc,
An electrode roll coated with a thin layer of one kind of metal selected from the group consisting of gallium, indium, and aluminum or an alloy of two or more kinds of metals. 2. The electrode roll according to claim 1, wherein the fusible alloy mainly containing gallium is composed of a four-element alloy composed of gallium, indium, tin and zinc.