JP2820815B2 - Manufacturing method of electrode for resistance welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode used for resistance welding of a metal plate such as an aluminum alloy plate.

[0002]

2. Description of the Related Art Conventionally, an electrode used for resistance welding of an aluminum alloy plate or the like has a very small area within a surface (tip pressing surface) abutting on the metal plate at the time of welding due to a difference in current-carrying resistance of a contact surface. There is a problem that the current tends to be concentrated in the portion, and in the portion where the current is concentrated, deposits are formed on the electrode or the electrode is damaged, and the life of the electrode is shortened.

The cause of the above problem is considered as follows. In the resistance welding, a metal plate (a work member) such as an aluminum alloy plate is provided between electrodes provided opposite to each other in a welding device.
The parts to be welded are overlapped and inserted, and current is supplied in a state where the tip pressing surface of the electrode is pressed against the parts, and the parts are heated by the resistance of the metal plate and welded to weld. How to do it. In this method,
When welding a relatively soft material such as aluminum, it is common to use an electrode whose tip pressing surface is shaped into a convex spherical surface so as not to cause deformation and cracks around the welded portion of the metal plate. . However, in the case of a metal plate such as an aluminum alloy plate, a non-uniform oxide film is generally formed on the surface of the metal plate. When the tip pressing surface of the electrode is pressed against such a metal plate, a current is applied to a weak portion of the oxide film. concentrate. When an attempt is made to supply power to the metal plate from the electrodes in this state, the metal oxide film generally acts as a resistor during energization, so that current flows through the metal plate only through the weak portion of the oxide film, and in the portion where the current is concentrated, If the temperature rises excessively, sticking between the electrode and the metal plate occurs, and the substance generated by the sticking adheres to the electrode, or conversely, the electrode is broken. That is, it is considered that the above problem occurs due to the magnitude of the resistance value of the oxide film.

In order to solve the above-mentioned problem, there has been proposed an electrode in which a pressing surface at the tip of a welding electrode is processed so that the oxide film can be totally destroyed at a portion where the electrode comes into contact. According to such an electrode, when the tip pressing surface of the electrode is pressed against the metal plate for welding, the oxide film is destroyed at the entire portion where the tip pressing surface abuts, and the electrode is brought into contact with the unoxidized portion of the metal plate. The contact part increases. As a result, it is possible to prevent the current from being uniformly supplied from a wide range on the electrode and to be locally concentrated, thereby prolonging the life of the electrode.

As such an electrode, for example, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 8-159986 proposes an electrode in which a groove having a triangular or trapezoidal cross-sectional shape is formed in a concentric or spiral shape formed by a plurality of annular grooves on a pressing surface of the electrode. In the electrode, an apex of a portion sandwiched between the grooves forms an annular or spiral ridge having an acute angle.
According to the description of the above publication, by using an electrode having a groove having the above-described shape formed on the tip pressing surface, when the tip pressing surface of the electrode is pressed against a metal plate for welding, the ridge portion is formed. Breaks the oxide film on the surface of the metal plate, so that the portion of the electrode in contact with the unoxidized portion of the metal plate can be increased, and welding can be advantageously performed.

However, in the electrode disclosed in the above publication, the current load tends to concentrate on the center of the electrode in the groove formed on the tip pressing surface of the electrode which is shaped into a convex spherical surface during welding. In addition, there is a disadvantage that a product generated by fusion of the electrode and the metal plate at the time of welding adheres to the entire portion, and the appearance quality of the work to be welded is deteriorated and the strength variation is increased.

Further, according to the description of the above publication, the grooves formed on the tip pressing surface of the electrode are processed by a lathe, so that the surface roughness of the tip pressing surface is large, and the tendency of the product to adhere is high. However, there is an inconvenience that much time and labor are required to smooth the surface of the groove.

Japanese Unexamined Patent Application Publication No. Sho 62-156085 proposes an electrode in which unevenness is formed by shot blasting a pressing surface at the tip of the electrode. According to the description of the above-mentioned publication, the effective life of the electrode is extended by forming irregularities on the pressing surface at the tip end of the electrode, and welding can be continuously performed many times with the same electrode. However, since the electrode disclosed in the above-mentioned publication performs the formation of irregularities on the pressing surface at the tip of the electrode by shot blasting,
It is difficult to form projections of uniform size, and it is difficult to process the electrodes on a production line. Also,
It was not possible with the above-mentioned prior art to process the tip pressing surface of the electrode into a complicated shape.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages. An object to be welded having excellent appearance quality and joining quality is obtained, and a long-life resistance welding electrode is provided. It is an object of the present invention to provide a method of manufacturing easily and at low cost.

[0010]

In order to achieve the above object, a method of manufacturing an electrode for resistance welding according to the present invention provides a method of supplying an electric current in a state where a work member made of a metal plate is pressed against a superposed portion. In a method of manufacturing an electrode in which a portion is heated by the electrical resistance of a work member and welded by welding, the powder of the electrode material is placed in an electrode molding die in which a plurality of concave portions having a substantially V-shaped cross section are regularly arranged. A molding step of obtaining a preformed body of an electrode in which a plurality of protrusions whose tips are thinner than the base independently of each other are formed by pressure-forming the filled powder and granules, A firing step of firing the preformed body obtained in the above step to obtain a sintered formed body of the electrode.

The term “substantially V-shaped cross section” means
It also includes an inverted trapezoidal shape in which the V-shaped bottom is straight or curved.

Further, in the method for producing an electrode for resistance welding according to the present invention, a powdery material of an electrode material is filled in a metal mold for electrode forming, and the filled powdery material is subjected to pressure molding so that one end is substantially formed. A preforming step of obtaining a preformed body of the electrode having a smooth convex spherical shaped surface, a firing step of firing the preformed body obtained in the above step to obtain a sintered body of the electrode, By pressing a shaping tool for applying a projection thinner than the base to the electrode on at least one surface to the shaping surface of the electrode molded body obtained in the above step, the electrode sintered body is independently formed from the electrode sintered body. Forming a plurality of protrusions having a tip thinner than the base.

[0013] The powder of the electrode material may be a powder containing an electrolytic copper powder as a main component and containing chromium powder, or a powder containing an electrolytic copper powder as a main component and containing chromium powder, aluminum powder and titanium powder. Etc. can be used. It is preferable that the granules containing the electrolytic copper powder as a main component are wet-mixed in ethanol and used.

[0014]

According to this method, a preform of an electrode having a plurality of projections independently of each other and having a tip thinner than a base is formed of a plurality of electrode materials made of a powdery or granular material having a substantially V-shaped cross section. Are directly obtained by pressure molding using a regularly arranged electrode molding die, so that the projections have a smooth surface. Since the projection has a sufficiently smooth surface to reduce adhesion of a product generated by fusing the electrode and the work member during resistance welding, until the machining is performed again. In addition, by firing the pre-formed body, a sintered formed body of the electrode can be obtained. Therefore, the manufacturing time required for machining or the like of the resistance welding electrode having the protrusion is reduced, and the cost is also reduced.

According to another method of the present invention, a preform of an electrode having one end face having a smooth convex spherical shaped surface is formed by using a metal mold as an electrode material made of powder and granules. And directly obtained by press molding. Then, after firing the pre-formed body, by forming a plurality of protrusions whose tips are thinner than the base independently of each other on the shaping surface of the obtained sintered body, a resistance welding having the protrusions is provided. An electrode is obtained. Since the projections are formed on a smooth shaping surface, the tips are smooth and need not be machined again. Accordingly, the manufacturing time of the electrode for resistance welding having the protrusion is reduced, and the cost is also reduced.

[0016]

Embodiment 1 Next, a method for manufacturing an electrode for resistance welding according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a flowchart showing the manufacturing process of the present embodiment, FIG. 2 is an explanatory sectional view showing a pressure forming method in the forming process of the present embodiment, and FIG. 3 is obtained by the manufacturing method of the present embodiment. Explanatory sectional view of the electrode for resistance welding, FIG. 4 is a plan view showing a tip pressing surface of the electrode for resistance welding obtained by the manufacturing method of the present embodiment, and FIG. 5 is a sectional view taken along line V─V in FIG. .

FIG. 6 is a plan view showing a pressing surface at the tip of a resistance welding electrode in which another shape is formed by applying the manufacturing method of this embodiment.

FIG. 7 is a flowchart showing a manufacturing process of another embodiment, and FIG. 8 is an explanatory sectional view showing a pressure forming method in a preforming process of another embodiment.

Next, the manufacturing method of this embodiment will be described with reference to the flowchart of FIG.

In the manufacturing method of this embodiment, first, 97.5% by weight of the total weight of electrolytic copper powder having an average particle diameter of 44 μm, and 2.5% by weight of the average particle diameter of 1. 6μ
m of chromium powder was mixed to prepare a powder material mixture of an electrode material.

Next, the above-mentioned powder mixture was wet-mixed in a ball mill using ethanol as a mixing medium, and the chromium powder was uniformly dispersed in the electrolytic copper powder.

Next, the powder mixture was adjusted to be contained at 12 to 13% by weight in the ethanol of the mixed medium solution, and then charged into an electrode molding die 21 shown in FIG.

The electrode molding die 21 is formed by a molding plate 22.
And a forming hole 23 provided vertically through the forming plate 22.
And an upper punch 24 and a lower punch 25 that are inserted into the forming holes 23. The upper punch 24 and the lower punch 25 are each driven by a pressing device (not shown),
A molding hole 23 is provided slidably up and down.

The forming hole 23 has a diameter corresponding to the electrode to be formed. In the present embodiment, the diameter D is φ22.6 m.
m. The upper punch 24 has a sliding pressure portion 26 that slides in contact with the inner peripheral side of the forming hole 23, and further has a core punch 2 that extends below the central bottom of the sliding pressure portion 26.
7 is provided. The lower punch 25 has a molding hole 23 in the upper part.
And a sliding pressure portion 28 that slides in contact with the inner peripheral side of the hole. The upper end surface of the sliding pressure portion 28 is a plane orthogonal to the central axis of the forming hole 23.

Then, on the upper end surface of the sliding pressure portion 28,
A plurality of concave portions 29a having a substantially V-shaped cross section are formed. The concave portions 29a are partitioned by a plurality of protrusions 29b having a trapezoidal cross section provided to be orthogonal to each other, and are arranged in a lattice shape. The bottom of the concave portion 29a is formed so as to form a part of the concave spherical surface.
The surface connecting the bottom of 9a is a 150R spherical surface.

[0027] It is arranged and configured as described above,
The concave portion 29a is formed to be deeper toward the center of the lower punch 25 and slightly shallower at the peripheral portion, and 0.8 m at the deepest portion.
m. The angle between the two slopes that oppose each other and forms the substantially V-shaped cross section of the concave portion 29a is formed to be 90 °, and the distance between the centers of the concave portions 29a is 3.0 mm. It is formed to become.

In the electrode molding die 21 having the above structure,
In the state in which the lower punch 25 was fixed at a predetermined position in the forming hole 23, the powder mixture was slid upward to move the upper punch 24 to open the upper surface of the forming hole 23, and the powder mixture was released. It was thrown in from the upper surface of the forming hole 23. After the powder mixture is charged and filled, the upper punch 24 is again inserted into the forming hole 23 and slid downward to cooperate with the lower punch 25, and the powder is pressed at a pressure of 150 MPa by the pressing device. The granule mixture was subjected to hydrostatic pressure to obtain an electrode preform 30.

In the preformed body 30, the shapes of the concave portions 29a and the projections 29b formed above the sliding pressure portions 28 of the lower punch 25 are transferred to the surfaces to be the pressure pressing surfaces of the electrodes. ing. Further, a portion serving as a cooling water hole of the electrode is formed by a core punch 27 on the upper part of the preform 30.

Next, the pre-formed body 30 is
After holding at 60 ° C. for 6 hours, the temperature was raised to 150 ° C., and further kept for 4 hours to dry.

Next, the preform 30 was fired according to the following procedure to obtain a sintered compact, and an electrode for resistance welding was obtained.

First, the pre-formed body 30 dried as described above is placed in a nitrogen atmosphere at a flow rate of 2 liters per minute, at a rate of 1 minute per minute.
After the temperature was raised to 350 ° C. at a rate of 0 ° C. and maintained at that temperature for 1 hour, the temperature was further raised to 485 ° C. at a rate of 10 ° C./min and maintained at that temperature for 1 hour. In the baking process, a protective film of a ceramic containing nitride is formed on the surface of the chromium particles, so that the strength of the electrode is improved. When an electrode reinforced with such ceramics is used, even if the electrode is pressed against a work member at the time of welding, damage and wear of the electrode are reduced and the life is extended.

Further, after the temperature is raised to 900 ° C. at a rate of 10 ° C. per minute and maintained at that temperature for 30 minutes, nitrogen gas is sealed so that the furnace pressure becomes 5 bar in order to stabilize the ceramic protective film. did. Next, the temperature was raised to 980 ° C. at a rate of 10 ° C./min and maintained at that temperature for 30 minutes, and then raised to 1030 ° C. at a rate of 5 ° C./min and maintained at that temperature for 30 minutes. The temperature was raised to 1050 ° C. at a rate of 5 ° C. per minute and kept at that temperature for 30 minutes.

After the above treatment, the temperature was immediately lowered to 1000 ° C., maintained at that temperature for 4 hours, rapidly cooled by oil cooling, and subjected to an aging treatment at 500 ° C. for 2 hours.

The resistance welding electrode obtained by sintering the powder-particle mixture in the firing step has a density of 8.92 g / c.
It exhibited physical properties of m ³ , hardness H _RB 78 and tensile strength of 58 kgf / mm ² , and the theoretical density was almost 100%. Analysis of the resistance welding electrode indicated that it contained about 0.18% by weight of nitrogen.

As shown in FIG. 3, the resistance welding electrode 31 obtained by the above-described manufacturing method has a cooling water hole 32 which is substantially cylindrical and has an upper opening at the center.
The lower end is a tip pressing surface 33. A plurality of projections 34 are formed on the distal end pressing surface 33 independently of each other, and the distal ends thereof are thinner than the base, and a valley 35 is formed between the projections 34.

The tip of the projection 34 is formed so as to form a part of a convex spherical surface, and the surface connecting the tip of the projection 34 is
As shown by the phantom line in FIG. 3, it is a 150R convex spherical surface. The surface connecting the valleys 35 is a plane orthogonal to the central axis of the resistance welding electrode 31 as shown by a virtual line in FIG.

As shown in FIG. 4, the protrusions 34 have a truncated quadrangular pyramid shape, are partitioned by a plurality of valleys 35 formed orthogonal to each other, and are arranged in a lattice. The area of the tip of the projection 34 is smaller toward the center of the tip pressing surface 33.

As described above, the surface connecting the tips of the projections 34 is a spherical surface of 150R, and the surface connecting the valleys 35 is a plane orthogonal to the center axis of the resistance welding electrode 31. For this reason, the height h of the projection 34 increases toward the center of the front end pressing surface 33 as shown in FIG. Protrusion 3
The height h of 4 is 0.8 mm at the highest part.

Further, as shown in FIG.
The angle θ formed by the two slopes forming the valley 35 between 4 and 34 is 90 °, and the distance P between the centers of the projections 34 is 3.0 mm. Is formed.

In the resistance welding electrode 31, during welding, loads such as welding pressure, current, heat generation, etc. are concentrated toward the center of the tip pressing surface 33, but as described above, the center of the tip pressing surface 33 is higher. The formation of the sharp projection 34 having a small area of the portion is advantageous because the load can be reduced.

A protrusion 34 having an effective function is provided on the tip pressing surface 33 of the resistance welding electrode 31 obtained in this embodiment.
It is formed in six places.

In the manufacturing method of this embodiment, the powder mixture of the electrode material is mixed with a lower punch having a plurality of recesses 29a having a substantially V-shaped cross section arranged regularly on the upper end surface of the sliding pressure unit 28. Since the preformed body is obtained by filling into the electrode forming die 21 provided with the mold 25 and press-molding, the protrusion 3
Form 4 is formed directly from the granule mixture. As a result, the projection 34 has a sufficiently smooth surface to reduce the adhesion of products generated by fusion of the electrode and the workpiece during resistance welding, and is again subjected to machining or the like. Not even. Accordingly, the resistance welding electrode 31 having the projections 34 can be manufactured in a short time, and the cost can be reduced.

A welding test was performed using the electrode 31 for resistance welding. Welding is performed by superposing aluminum alloy plates having a thickness of 3.0 mm and 3.5 mm corresponding to JIS A5182 from above and below the superposed portion of the aluminum alloy plate using the resistance welding electrodes. Welding was performed at a pressure of 1200 kgf at a welding current of 42 kA for 15 cycles, and a test was conducted to determine how many consecutive hit points were obtained.

The above test results show that the number of hit points at which an effective nugget was sufficiently generated and the breaking strength of not less than the minimum guaranteed strength of 1300 kgf was obtained was referred to as “continuous hitting property”. The number of hit points until the outside break-out or weld cracking occurred in the portion was expressed as "effective continuous hitting property", and was used as an index for evaluating the life of the electrode. In the evaluation method, the larger the value of the continuous hitting property and the effective continuous hitting property, the longer the life of the electrode. Table 1 shows the continuous spotting property and the effective continuous spotting property of the resistance welding electrode.

In this embodiment, the resistance welding electrode 31 is used.
A plurality of protrusions 34 whose tips are thinner than the base are formed independently of each other on the tip pressing surface 33 of the first embodiment. However, according to the manufacturing method of this embodiment, the powder material mixture of the electrode material is pressed and formed. By doing so, an electrode is obtained.
In addition, it is possible to easily manufacture a resistance welding electrode in which patterns such as characters and symbols are formed on the tip pressing surface 33.
In this case, in the electrode molding die 21 shown in FIG. 2, a concave spherical surface is formed on the upper end surface of the sliding pressurizing portion, and the concave spherical surface has a convex or concave portion having a pattern such as a character or a symbol. May be used as the lower punch.

Such an electrode for resistance welding is, for example, shown in FIG.
As shown in FIG. FIG. 6 is a plan view of the resistance welding electrode in which patterns such as characters and symbols are formed on the tip pressing surface 33. The resistance welding electrode 61 has a plus sign 62, and the resistance welding electrode 63 has a plus sign 62. A letter 64 is formed on the resistance welding electrode 65, and a letter 66 is formed on the resistance welding electrode 67.

When welding is performed using the above-described electrode for resistance welding, a lattice pattern, characters 64, 6
6. Since the patterned shapes such as symbols 62 and 68 are transferred to the work to be welded as welding marks, an added value not only serving as welding marks can be obtained. That is, welding quality can be estimated based on whether or not a clear welding mark can be obtained, and a function of distinguishing a product of one's own from a product of another company can be provided.

[0049]

Embodiment 2 Next, a manufacturing method of another embodiment will be described with reference to the flowchart of FIG.

First, in the same manner as in Example 1, a powder-particle mixture of an electrode material was prepared, wet-mixed, and charged into an electrode molding die 81 shown in FIG. The electrode molding die 81 is the same as that of the first embodiment.
The configuration is the same as that of the electrode molding die 21 used in the above.
The only difference is that an R-shaped concave spherical surface 84 is formed. In the electrode forming die 81, the electrode forming die 2
The same components as those in 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Next, in the same manner as in Example 1, the upper and lower punches 24 and 82 cooperate with each other to hydrostatically press the powder mixture at a pressure of 150 MPa.
An electrode preform 85 having a size of 6 × 125 mm and a smooth convex spherical surface at one end was obtained.

Next, the preform 85 was dried and fired in the same manner as in Example 1 to obtain a sintered body having a smooth convex spherical shaped surface at one end. The sintered body had a density of 8.92 g / cm ³ , a hardness of H _RB 78 and a tensile strength of 58 kg.
It showed physical properties of f / mm ² and the theoretical density was almost 100%.

In the sintered body, a protective film of a ceramic containing nitride is formed on the surface of the chromium particles in the firing step, as in the first embodiment.

Next, the sintered body was converted into an electrode shaping tool made of a cemented carbide mold in which a plurality of concave portions having a substantially V-shaped cross section, such as the upper end surface of the lower punch 25 of Example 1, were regularly arranged. ,
Pressing using a 1000 ton mechanical press, forming a plurality of truncated quadrangular pyramid-shaped protrusions whose tips are thinner than the base independently of each other on the shaping surface of the sintered body to obtain an electrode for resistance welding. . The processing for forming the truncated quadrangular pyramid-shaped projections was performed by applying molybdenum disulfide to the sintered body in order to improve the sliding characteristics of the sintered body. The shape of the truncated quadrangular pyramid-shaped projection formed by the above-described processing is the same as the truncated quadrangular pyramid-shaped projection 34 formed on the resistance welding electrode 31 of the first embodiment shown in FIGS.

In the manufacturing method of the present embodiment, the powder mixture of the electrode material is mixed with an electrode forming metal provided with a lower punch 82 having a 150R concave spherical surface 84 formed on the upper end surface of the sliding pressure portion 83. Since the mold 81 is filled and molded under pressure, a preformed body 85 of the electrode having one end face having a smooth convex spherical shaped surface is directly obtained from the powder-particle mixture. Then, by pressing the electrode shaping tool against the shaping surface of the sintered body obtained by firing the pre-formed body 85, the same as the protrusion 34 formed on the resistance welding electrode 31 manufactured in Example 1 The electrode for resistance welding in which the protrusion having the shape of (1) is formed is obtained. Since the shaping surface has a sufficiently smooth surface to reduce the adhesion of products generated by welding the electrode and the workpiece during resistance welding, the tip surface of the projection is machined again. It is so smooth that it does not need to be processed. Accordingly, the electrode for resistance welding having the protrusion can be manufactured in a short time, and the cost can be reduced.

A welding test was carried out in the same manner as in Example 1 using the resistance welding electrode. Table 1 shows the continuous spotting property and the effective continuous spotting property of the resistance welding electrode.

[0057]

Comparative Example 1 A commercially available chrome copper electrode material was used, and the tip of the material was processed into a convex spherical surface to produce an electrode for resistance welding. No protrusion is formed at the tip of the electrode independently of each other and the tip is thinner than the base.

A welding test was performed using the electrodes. The welding conditions were a welding pressure of 1600 kgf and a welding current of 4
Except for 6 kA, it is the same as the above embodiment. Since the electrode of this comparative use example does not have a projection at the tip, and it is considered that the action of breaking the oxide film of the work member becomes insufficient, the pressing force and the welding current are set to be larger than those of the example.

Table 1 shows the continuous spotting property and the effective continuous spotting property of the resistance welding electrode of this comparative use example.

[0060]

[Table 1]

As is apparent from Table 1, the resistance welding electrode obtained by the manufacturing method of the present invention has a longer service life than the conventional chromium copper resistance welding electrode having a convex spherical tip. Has been significantly extended.

[0062]

As is evident from the above, according to the manufacturing method of the present invention, a plurality of protrusions whose tips are thinner than the base independently of each other and whose surface is smooth are free from defects. The formed electrode for resistance welding can be efficiently manufactured in a short time, and the manufacturing cost can be reduced.

According to the resistance welding electrode, a good welding mark is obtained without sticking or the like, the appearance quality of the workpiece is improved, and the life of the electrode is extended.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of an embodiment according to a manufacturing method of the present invention.

FIG. 2 is an explanatory cross-sectional view showing a pressure molding method in a molding step of Example 1.

FIG. 3 is an explanatory sectional view of a resistance welding electrode obtained by the manufacturing method of Example 1.

FIG. 4 is a plan view of a tip pressing surface of the resistance welding electrode obtained by the manufacturing method of the first embodiment.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a plan view of a tip pressing surface of a resistance welding electrode in which another shape is formed by applying the manufacturing method of the first embodiment.

FIG. 7 is a flowchart showing a manufacturing process of another embodiment according to the manufacturing method of the present invention.

FIG. 8 is an explanatory sectional view showing a pressure forming method in a preforming step of Example 2.

[Explanation of symbols]

21 ... electrode molding die, 25 ... lower punch, 29a ... V
A concave portion having a U-shaped cross section, 31 ... electrodes for resistance welding, 33 ...
Tip pressing surface, 34: protrusion, 35: trough, 81: electrode shaping mold, 84: concave spherical surface.

Continuing from the front page (72) Inventor Tamotsu Harada 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (72) Inventor Yukihiro Yaguchi 1-10-1 Shinsayama, Sayama City, Saitama Honda Engineering Stock In-company (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 11/30

Claims (2)

(57) [Claims] In a method of manufacturing an electrode, a current is supplied in a state where a work member made of a metal plate is pressed against an overlapped portion, and the portion is heated by the electric resistance of the work member in the portion to generate heat and weld the electrode. A plurality of concave portions having a U-shaped cross-section are filled with electrode material powder in an electrode molding die in which regularly arranged electrodes are formed, and the filled powder particles are subjected to pressure molding so that the tips thereof are independent of each other. From a forming step of obtaining a preformed body of the electrode on which a plurality of projections thinner than the base are formed, and a firing step of firing the preformed body obtained in the step to obtain a sintered formed body of the electrode A method for producing a resistance welding electrode, comprising: 2. A method of manufacturing an electrode, comprising: supplying an electric current in a state in which a work member made of a metal plate is pressed against an overlapped portion; and heating and welding the portion by electric resistance of the work member in the portion. An electrode material is filled with a powder material of an electrode material, and the filled powder material is subjected to pressure molding to obtain a preformed body of an electrode having one end having a substantially smooth convex spherical shaped surface. A preforming step, a firing step in which the preformed body obtained in the above step is fired to obtain a sintered body of the electrode, and a projection whose tip is thinner than its base is applied to the electrode on at least one surface. Pressing a shaping tool against the shaping surface of the electrode sintered body obtained in the step, forming a plurality of protrusions on the electrode sintered body independently of each other, the tips of which are thinner than the base. Of an electrode for resistance welding characterized by comprising: Method.