JP2855016B2 - Aluminum-based resistance welding method and insert member - 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 resistance welding of an aluminum-based material such as aluminum or an aluminum alloy (hereinafter referred to as an aluminum-based material), and a method of welding the same.
It relates concert members, even more particularly, to lap resistance welding method and the insert member of an aluminum-based material.

[0002]

2. Description of the Related Art As one of conventional joining methods of aluminum plate materials (aluminum-containing alloy plate materials), there is a method disclosed in Japanese Patent Application Laid-Open No. 58-47576. In this method, an anodic oxide film or a chemical oxide film is formed in advance on the overlapped portion of the aluminum plate and welded.After the work is coated with a margin, the work is immersed in a sulfuric acid bath to form an anodic oxide film. , That part is welded.

[0003] In this case, not only the number of steps up to welding is large, but also a processing bath is required, so that there is a disadvantage that the cost is increased.

[0004] In general, when resistance welding is performed on an aluminum plate, there is a tendency that the pressing force and welding current must be increased because the aluminum has high electrical conductivity. In addition, an oxide film is formed on the surface of the aluminum material, which becomes a resistor, and is sandwiched between the electrode chip and the work contact surface. As a result, heat is generated also in this portion, and as a result, dust and welding are generated. Therefore, there were problems such as deterioration of appearance quality. Note that the occurrence of dust, welding, and the like also affects the life of the electrode chip, and has the disadvantage of shortening the life.

Another prior art is disclosed in Japanese Unexamined Patent Publication No.
There are also those such as 78679 and JP-A-55-100882.

In Japanese Patent Application Laid-Open No. 63-278679, there is a drawback that the insert material (plate material) is provided at the welding portion in advance, which is wasteful and costly.

In Japanese Patent Application Laid-Open No. 55-100882, since the insert material is a plate-like solid such as a disk or a plate, it is necessary to set the insert at each welding point. Therefore, it is good when the work is a single work (one with one hit point and the welding is completed), but there is a drawback that when the work is welded continuously, the work becomes difficult.

There is also a disadvantage that the cost of the insert material is increased because a plate-like solid material is used.

Further, Japanese Patent Application Laid-Open Nos. 64-62284 and 63-1 disclose techniques for interposing a substance for increasing the resistance between the plates between the plates to be welded.
Japanese Patent Application Laid-Open No. 1998-88 and Japanese Patent Application Laid-Open No. 1-254388. Each of these sheet materials is a galvanized steel sheet, and the inclusions are Al ₂ O ₃ (particle size: 50 to 500 μm), mending tape (thickness: 0.1 mm), salt particles (particle size: 250 mm).
μm) and MnSi ₂ (particle size: 100 μm).

[0010] In these methods, by inserting inclusions,
The aim is to increase the resistance of the part, thereby reducing the current and shortening the conduction time, reduce the amount of zinc lost from these two, improve the corrosion resistance and extend the life of the electrode. . Also, by forming a nugget between the plates to be welded, the aim is to improve the strength.

However, when the above-mentioned inclusions are used for the aluminum-based material to be welded according to the present invention, the welding characteristics are rather deteriorated. Therefore, such inclusions cannot be applied to the present invention. The reason is as follows.

The surface of the aluminum material is easily oxidized,
Usually, it is covered with the oxide film of Al ₂ O ₃ . The affinity between aluminum and oxygen is one more than the affinity between Zn and O _2.
It is about 00 times larger. Therefore, the thickness of the oxide film Al ₂ O _{3 on} the surface of the aluminum material is much larger than the thickness of the oxide film on the surface of the galvanized steel sheet. Further, the resistivity ρ of Al ₂ O ₃
Since Al is large as 1 × 10 ¹⁶ Ω · cm (14 ° C.), if Al ₂ O ₃ is further used as an inclusion, the resistance between the electrodes to be welded becomes too large, and welding can no longer be performed. In this case, if a material having a large particle size of 50 μm to 500 μm is used, as in JP-A-64-62284, the resistance is further increased and welding becomes more and more impossible.

[0013] In addition, regarding the welding strength after welding, the use of inclusions can only be expected to improve the strength due to the reduced thermal effect on the base material. That is, when using Al ₂ O ₃ as inclusions, since Al ₂ O ₃ and the member being welded to an inclusion is not be alloyed or combined by welding, the weld strength by such that This is because improvement cannot be achieved. Rather, when the plate material to be welded is an aluminum material, the particle size is 50 to 500.
When Al ₂ O ₃ grains of μm are interposed, the strength is rather deteriorated, and further, under stress, the Al ₂ O ₃ grains become a source of fracture.

Further, when the mending tape is used as the inclusion, since the mending tape itself is too thick, it is impossible to conduct electricity between the plates to be welded as in the case of using Al ₂ O _3. Welding cannot be performed.

Further, when salt grains are used as the inclusions in the aluminum material, the welding strength is reduced.

Further, the plate material to be welded is made of aluminum.
Material, MnSi as an inclusion _TwoWhen using
In addition, Mn and Si cause a needle-like phenomenon,
The welding strength decreases.

The present invention was made focusing on the above problems, aims to provide a resistance welding method results in improvement of efficiency and external appearance of the resistance welding, a high service life of the electrode material And In addition, the present invention provides a
Between the aluminum plates, and thus between the aluminum plates
Made of a weak conductive material or conductive material
It is an object of the present invention to provide an insert member.

[0018]

According to the present invention, in a resistance welding method for an aluminum-based material in which an insert member is interposed at a joint surface when aluminum-based material is resistance-welded , Fe, Fe, Ni,
At least one selected from the group consisting of Co, Cr, Ti
And the semiconductor material is 30 to 40% by weight of the semiconductor material.
By using a mixed powder obtained by mixing at a ratio of, and applying a solution obtained by mixing the powder , the powder is interposed in the bonding surface, and an oxide film on the surface of the aluminum-based material is removed at the time of energization. Is the same as the aluminum-based material
Resistance welding method of aluminum-based material, characterized in that the serial insert member is complexed or alloys are obtained.

According to the present invention, there is provided an aluminum-based material.
Aluminum material interposed at the joint surface during resistance welding of steel
Fe, Ni, C
o, Cr, and at least one selected from the group consisting of Ti
The semiconductor substance is 30 to 40% by weight of the semiconductor substance;
Aluminum-based, characterized by being mixed in proportions
An insert member for resistance welding of the material is obtained.

The aluminum material has a high conductivity, and has a large electric current when performing resistance welding, compared to SP steel sheets and galvanized steel sheets.
Requires high pressure. Therefore, in order to maintain sufficient heat generation and enable welding, increase the current-carrying area by enlarging the current-carrying area (increase the electrode tip diameter) or increase the resistance of the weld between aluminum materials. Need to be done.

Now, as shown in FIG.
Insert member 1 that increases resistance between workpieces between 12
When 5 is inserted, a preferential heat generation site is provided in that portion, so that the Joule heat generation efficiency can be increased and the generation site can be limited. At this time, if conditions such as the amount, type, particle size, and particle size of the insert member 15 are appropriately determined, it is expected that a great effect can be obtained by a simple method of interposing a substance between works.

If the insert member 15 interposed between the workpieces is made of powder, a flash should occur for a very short time in the initial stage of energization. This is because the powder has a small contact particle area and a large current is concentrated here.

On the other hand, the surface of the aluminum material is generally covered with Al ₂ O ₃ which is an oxide film. Therefore, at the time of resistance welding, an oxide film having a high electric resistance is sandwiched between the aluminum plates. Therefore, it is considered that this portion is initially melted by energization. However, it is well known that the aluminum material has high thermal conductivity and the nugget moves to above or below the oxide film. In particular, in the case of direct current, this phenomenon is remarkable, and the nugget is biased to the + side. This is a phenomenon that is often seen in TIG welding, but eliminates the effect of such an oxide film.
We thought that bringing the nugget to the center would improve weldability. In order to eliminate the influence of the oxide film, it is preferable to break the oxide film. In this case, too, a powder having a high resistance is interposed between the oxide films, at least having a resistance higher than that of the base material such as an aluminum material. It is considered suitable.

Now, considering the above, if the powder is interposed between the aluminum plates to be welded, as shown in FIG.
Since the aluminum plates 21 and 25 face each other via the powder 23 and the outlet of the large current is limited, it is possible to easily estimate that the arc will fly. This is in a plasma state, and has sufficient energy to destroy the oxide films 22 and 24. When the current value is several KA (direct current) or several hundred A, the energy obtained by this flash is several tens μm generated on the aluminum plates 21 and 25.
It has the ability to destroy the thick oxide films 22, 24. Therefore, the oxide films 22 and 24 are removed by the flash, and a clean metal surface appears, which is welded.

Electrode 1 after energization and flashing
Considering the resistance between the electrodes 3 and 14, as shown in FIG.
2. resistance 33 in the work 11, resistance (contact) 34 between the work 11-insert member (powder) 15-work 12,
It is a series resistance of the resistance 35 in the work 12, the contact resistance 36 between the work 12 and the electrode 14, and the internal resistance 37 in the electrode 14. Of these, in resistance welding, as is well known, the resistance 34
When the resistance is overwhelmingly larger than other resistances, welding with high efficiency and high welding strength can be performed. An insert member (powder) 15 sandwiched between the clean metal surfaces created by the flash is arranged to raise and control this resistance 34.

For this reason, after the flash, a rise in the temperature of the metal on the clean metal surface, that is, so-called Joule heat is selectively generated here. If the temperature rises, the electric resistance further rises exponentially, so that this part eventually melts and becomes composite or alloyed with the interposed insert member (powder) 15.

In the later stage of welding, the power supply is stopped, and the heat of the molten portion is diffused to the base material and the electrode by heat conduction. At this time, the used insert member (powder) 15 is contained in the nugget and solidified together with the melting of the contact portion. Since the thermal conductivity of the insert member (powder) 15 is usually about 1/1000 of that of the base material aluminum, the cooling rate is reduced.

In conventional resistance welding of aluminum materials, the cooling rate at this time is extremely fast and rapid cooling.
Cracks are likely to occur at the interface between the surrounding structure and the weld, and even if a post-heating current is applied, the heat conduction is too good and a great effect cannot be expected. Tissue was obtained.

FIG. 3 shows these welding models. Since there is a flash area, it is easy to think that time will be delayed, but after flashing, a clean metal surface will be welded, so the subsequent rise of current will be sharp, and in fact it will be faster than the delay It becomes.

Further, the interposed insert member (powder) 15 must be selected so as to be compounded or alloyed with the material of the work and not to impair the strength of the material. A sensible choice is to increase the strength or rigidity of the (material) weld by compounding or alloying.

As described above, the aluminum-based material
In the case of, an oxide film Al_TwoO_ThreeIs formed
(See FIG. 2). Therefore, the aluminum plates 21 and 25
The distance between the oxide film 22 and the powder 23 is
And 24 are added. This oxide film
Al which is 22 and 24_TwoO_ThreeAbout 1 × 10 ¹⁶
Because it is as high as Ω · cm, between aluminum plate materials 21 and 25
In order to pass a large current that enables welding,
It is necessary that the specific resistance of the powder 23 to be
You.

For example, when a powder made of Al ₂ O ₃ is used as the powder 23, the specific resistance of Al ₂ O ₃ is large. Must be reduced. On the other hand, since the surface of the aluminum plates 21 and 25 originally has irregularities,
If the particle size of the powder 23 becomes small and becomes equal to or less than the degree of the unevenness, the oxide films 22 and 24 come into contact with each other, and the significance of the interposition of the powder 23 is lost. Will be. Therefore, the powder 2 to be interposed
The material of No. 3 is required to have a small specific resistance to some extent. Semiconductors, metals and the like can be considered as materials satisfying this requirement.

Further, when the aluminum material is welded, the aluminum material is melted.
Thus, the powder 23 is taken into the inside by being compounded or alloyed with the material No. 3. Aluminum materials are generally brittle, and it is necessary to prevent impact fracture when objects hit. Therefore, the substance used for the powder 23 is preferably a substance that strengthens the aluminum material when incorporated into the aluminum material. Such materials include S
iC is Ni, Co, Fe, Cr, Ti among metals.
Is preferred. Note that these materials can be used alone or a plurality of materials can be used simultaneously.

The SiC has a particle size of 4 to 30 μm.
m, Ni, Co, Fe, C
The particle size of r and Ti is preferably in the range of 200 μm or less, more preferably in the range of 5 to 100 μm.
If the particle size is larger than this, the resistance value of the powder 23 becomes too large, and it becomes difficult for a current necessary for welding to flow.

When the particle size is small, the powder coating layer may be composed of multiple particles. That is, when a particle size smaller than this is used, the powder is superimposed on the powder, and it is possible to make the thickness of the superposed layer fall within the specified range.

When SiC is used as the material of the powder 23, a large current flows intensively in a portion where the SiC powder 23 is in contact with the oxide films 22 and 24. Oxide films 22, 24
Is removed, the clean metal surfaces of the aluminum materials 21 and 25 are exposed, and the portions are welded.
Thereafter, the portion to be welded is selectively heated, and if heated, the electrical resistance of Al becomes higher, so that this portion will eventually melt and take in the SiC powder therein.

Since SiC is a semiconductor, the resistance decreases as the temperature increases. Therefore, the oxide film (Al ₂
Once used to remove O ₃ ), it no longer serves as a preferential heating portion. However, SiC
After being taken into the aluminum material, it functions to strengthen the aluminum material, so that the strength of the welded portion increases.

As a material of the powder 23, Fe, Cr, N
Also in the case of using i, Co, and Ti, flash is generated at the beginning of energization and the oxide films 22 and 24 are removed in the same manner as in the case of SiC.

However, since these metals have a lower thermal conductivity than Al, the metal part is preferentially heated, and if heated, the electric resistance is higher, and the metal part is heated more and more. Finally, it melts. As described above, the case of Fe, Cr, Ni, Co, and Ti is different from the case of SiC in that it actively participates in the melting phenomenon not only at the initial stage of energization but also thereafter.

Incidentally, when these metals are also taken into the aluminum material, they work to increase the welding strength.

The present invention is applicable not only to aluminum materials but also to aluminum materials such as aluminum alloys.

The powder 23 is preferably powder 2
By applying a solution in which 3 is mixed, it is interposed on the joint surface. This solution is preferably a binder such as vinyl acetate, nitrocellulose, polystyrene, polyacrylic resin, or melamine resin, a solvent such as acetone, alcohol, thinner, triene, or hexane, (ethyl) cellosolve, ethyl phthalate, or phthalate. It is prepared using a developing agent such as butyl acid and a drying control agent such as butyric acid.
Note that these combinations can be freely set as appropriate.

[0043]

EXAMPLES Example 1 The comparative welding member is a sheet thickness of JIS A5052P or equivalent.
It was an aluminum material of 0 mm, and this aluminum material was made into two sheets and welded. The welding was performed using a DC resistance welder, and the welding conditions were a welding current of about 40 KA and a conduction time of 15 cycles. Electrode is chrome copper φ16 × 190
mm (water-cooled). As the powder interposed between the aluminum materials, SiC having an average particle size of 4.0 μm was used.
This was mixed with a solution of acetone + polyvinyl acetate + ethyl cellosolve at 10% by weight and applied between aluminum plates.
The pressing force was 750 kgf.

The results of this embodiment are shown in FIGS. FIG. 4 shows the relationship between the nugget diameter and the current.
Class guaranteed value

[0045]

(Equation 1)

When the conventional welding method is used as a reference, 2
Although a welding current of 8.2 KA or more is required, if the welding current is 9.8 KA or more in the method of the present invention,

[0047]

(Equation 2)

The following nugget diameter is obtained.

FIG. 5 shows the relationship between the nugget thickness and the current. In the above conventional welding method, 28.2 is used.
A nugget thickness of about 2.75 mm, which cannot be obtained with a welding current of KA, is obtained at 12.6 KA in the method of the present invention.

In the conventional method, dust was generated near the welding current of 27.5 KA and the welding electrode and the aluminum plate were stuck.
No dust or sticking occurred around 3KA.

The peel strength of the weld was 750 to 800 kg according to the conventional method, whereas it was 850 to 900 kg according to the method of the present invention.

Further, looking at the appearance quality and the electrode tip surface,
In the conventional method, the welding was performed on the specific welded material and the electrode at several spots, sticking was caused, and the appearance quality was poor at 20 to 30 spots, and the necessity of dressing the electrode occurred, but in the method of the present invention, Even with 100 or more dots, good appearance quality was maintained, and electrode dressing was unnecessary. Example 2 In the same manner as in Example 1, a material equivalent to A5052, a sheet thickness of 2.0 mm, and two layers were used, a welding cycle of 15 cycles, a pressure of 750 kgf, and water-cooled chrome copper φ16 × 1
A welding test was performed using 90 mm as an electrode, powders of Fe, Ni, and Co and a welding current of about 10 KA to 40 KA.

The volume resistivity of Fe, Ni, and Co is 10 × 10 ⁻⁶ Ω · cm, 7 × 10 ⁻⁶ Ω · cm, and 6.
5 × 10 ⁻⁶ Ω · cm, which is about 4 times, 3 times, and 2.8 times of the aluminum material, respectively.

Therefore, the average particle diameter is 5 μm.
m, 10 μm, 20 μm, and 40 μm.

The results are shown in FIGS. 6, 7 and 8.

The powder was mixed with a solution of acetone, alcohol, ethyl cellosolve, and butyl phthalate in nitrocellulose and sprayed. When the coating film is thick, the current cannot be applied, so the coating film thickness was set to several tens of μm.

First, in order to determine the optimum particle size of the powder, the guaranteed value of the class B

[0058]

(Equation 3)

The welding was performed at 30 KA to clear the above, and the judgment was made based on the tensile shear strength. FIG. 6 shows the result.

The fact that the properties of the powders are similar because of the group VIII congeners also acts, and the strength varies depending on the particle size rather than the type of powder. The tensile shear strength tends to decrease as the average particle size of the granules changes. This is presumed to be due to the fact that the time required for diffusion and alloying differs depending on the particle size of the powder until the applied powder is melt-alloyed by Joule heat. Microscopic observation by fracture surface after tensile shearing and cutting of the molten nugget portion confirmed that the aggregated particles on the inclusions increased with the increase in powder particle size. Therefore, it is considered that the tendency for the strength to decrease was attributed to this and became the starting point of the destruction.

On the other hand, Ni is selected from the group VIII elements Fe, Ni and Co, and the weight ratio of Ni: SiC is 60: 4.
When the test was carried out after welding under the same conditions, the improvement in the strength level was recognized, and the same was true for Fe and Co.

However, as the Ni grain size increased, the density decreased significantly, and the effect was reduced. The compounding ratio for the purpose of compounding is 95: 5, 9 by weight ratio of Ni and SiC.
0:10, 80:20, 70:30, 50:50, 4
It was examined up to 0:60, but when the SiC content ratio was 20 or less, the compounding effect was small, and when the SiC content ratio was 50:50 or more, the composition tended to decrease. Was.

FIG. 7 shows a change in the formed nugget diameter when the welding current is changed.

Compared to the normal radiation (nothing is inserted between the workpieces),

[0065]

(Equation 4)

The resulting welding current of the nugget that exceeds
Compared to the conventional 28 KA, the Fe powder is 13 KA and the Co is 15 KA, both of which are about 1/2. The powder diameter used here is about 5 μm in average diameter based on FIG.

The welding current for obtaining the same nugget in the order of Fe, Ni, and Co shifts to the large current side, suggesting that the welding current is related to the specific resistance of the insert.

When the welding current was 38 KA or more, dust was generated due to the high welding current.

The nugget cut surface after welding was
As a result of observation, it was found that the dendritic phase associated with melting → resolidification, cracks in the eutectoid layer, and blowholes seen as hydrogen tended to be reduced (compared with the conventional case). This is further reduced as compared to SiC alone. It is suggested that the cause is solid solution strengthening of the inserted Fe, Ni, and Co, and an increase in the amount of hydrogen solid solution at room temperature. Generally, hydrogen contained in aluminum material is 3ml / 100g
It is set to be Al or less, but tends to concentrate locally at the most delayed portion of solidification with melting. Therefore, after solidification,
When the amount of the solid solution is small, it is considered that this causes a delayed fracture or a crack formation that causes the gas to pass through the grain boundary. If a material having a relatively large amount of hydrogen solid solution even at room temperature is disposed here, it is considered that blowholes and cracks due to solidification are reduced, but the above results are considered to show this clearly.

It is considered that as a result, the shear strength was greatly increased.

It has long been known that the addition of Fe, Ni, and Co into an aluminum material increases strength, rigidity and the like.

Assuming that Fe, Ni, and Co were further compounded with SiC, a Group VIII metal was represented by Ni, and the change in the formed nugget diameter was examined based on the results of FIG.

Up to 40 KA, no dust was generated, and it was found that the welding current was effective in reducing the welding current.

The cracks and blowholes in the nugget part are VI
The situation was close to the situation where the group II was used alone, and a reduction effect was observed.

As an application method, a tape-shaped or ribbon-shaped F
A method using a thin film of e, Ni, Co or the like is also conceivable.

However, in these methods, since the diffusion distance is increased, there is a high risk of becoming a fracture starting point as an inclusion. In particular, the increase in fatigue strength) and the variation in strength are large, which is not an effective method.

As described above, from the results of Examples 1 and 2, in order to reduce the welding current, it is preferable to insert a powder having a resistance value equal to or higher than that of aluminum as a powder and to blow the nugget part accompanying melting and solidification. For the generation of holes and cracks, a material having poor thermal conductivity and a large amount of solid solution of hydrogen (even at room temperature) is good.
The following are suggested in addition to i, Fe, and Co.

Ti, Cr, V, B, Mn, Sb, Bi,
As, Ge ... Among these, those which do not impair the good properties of the aluminum material and which have further improved strength, rigidity, etc. include:
Ti, Cr, V, and Mn, as well as those with high use safety and large quantitative variation, include Ti and Cr.

Further, the effect of Ti and Cr as an insert material will be described below.

In the above experiment, Fe, Ni, and Co were used alone. However, the allowable range of the quantitative variation was relatively wide with respect to the aluminum material, and the resulting alloy and intermetallic compound Although the formation of the product is somewhat different, there is no problem even if it is used in combination, and for example, the same effect is obtained by using stainless steel powder.

It is known that Ti and Cr are often contained in an aluminum material and function as a reinforcing agent, similarly to Group VIII metals.

The volume resistivity is Cr: 15 × 10 ⁻⁶ Ω
Cm, Ti: 45 × 10 ⁻⁶ Ω · cm, 5 to 7 times and 15 to 18 times that of aluminum, respectively. Where Ti
It is considered that the powder is easily oxidized and the resistance value has increased.

In the composite state after welding, it has been found from Example 2 that if the powder particle size of the inserted material acts as an inclusion when the powder particle size is large, the dispersion of mechanical strength and the like become large. The diameter was about 5 μm. The powder is a reagent having a purity of 99.5% or more.

The aluminum material and welding conditions were the same as in Examples 1 and 2 for comparison.

FIG. 8 shows the change in the welding current and the generated nugget. The guaranteed value of class B is about 10 to 12 KA, which is lower than the conventional value, and is lower than when Fe, Ni, and Co are added. This seems to be related to the specific resistance, as we have seen.

Further, the shear strength after welding at 30 KA was 850-900 kgf for Cr and 800-85 kgf for Ti.
It was 0 kgf. Cr is a group VIII element Fe, Ni, C
Like o, alloying strengthening appeared, but the proportion of Ti seemed to be small.

Further, the blow holes of the nugget generated by welding and the cracks caused by solidification shrinkage are further reduced as compared with the case where a group VIII element is inserted, and the blow holes due to hydrogen disappear almost completely in Ti, and even in Cr, The reduction was confirmed. Although the cracks due to solidification are not as large as those of the SiC powder, the effect of Ti is large, and the effect of Cr is also recognized.

This is considered to be because Ti, Cr and the like, particularly Ti, have a large solid solution ability of hydrogen at room temperature.
Also, compared to the case of using Cr or Group VIII metal element, Ti
Although the rate of improvement in strength was low in this case, it is considered that the cause was that the solid solution of hydrogen could not increase the strength.

From the above results, it is presumed that the system obtained by combining Examples 1 to 3 and adding SiC + Group VIII metal + Hydrogen absorbent is the most efficient.

In an attempt, SiC: (Fe, Ni, Co):
(Cr, Ti) = 40:40:20, the welding current was about 10 KA (minimum current to obtain the guaranteed value of class B), and the tensile shear strength of the welding at the welding current of 30 KA was about 1000 kgf. I was

[0091]

As described above, according to the present invention, the welding current can be reduced, and the energization time can be shortened. If the current is I, the resistance is R, and the time is t, there is a relationship of electric energy E = I ² Rt, so that heat generation (high temperature) of the electrode can be prevented and the life of the electrode can be extended.

As described above, according to the present invention, the welding current can be reduced, the conduction time can be shortened, and the electrode can be prevented from becoming high temperature.
Therefore, the structural change due to the thermal influence around the nugget of the base material is reduced. Also, SiC, Fe, Cr, Ni, Co,
By interposing Ti between the aluminum plates, when the nugget portion is formed by welding, it is expected that the nugget portion is composited with these materials, and the strength of the penetration portion (nugget portion) is also improved.

As described above, according to the present invention, the structural change due to the thermal influence around the nugget is reduced, and the strength of the nugget part is improved, so that the welding strength is also improved.

[0094] By improving the welding strength as described above, the welding nugget can be reduced.
The diameter of the welding electrode can be reduced. Therefore, the length of the flange provided for resistance welding of the work can be shortened, and a complicated work shape can be handled. Further, if the size of the welding electrode is reduced, the pressing force (of the welding gun) can be reduced. If the reduction in the size of the welding electrode, the reduction in the welding current, and the reduction in the conduction time described above are taken into consideration, the size of the welding transformer can be reduced.

Therefore, conventionally, resistance welding of an aluminum plate requires a welding gun of high current and high pressure, which has been postulated to be robotized. However, according to the present invention, a small welding gun is used for the aluminum plate. Can be resistance-welded, so that a robot holding this gun can be used. In addition, the robot can be small in weight because the payload of the robot can be small.

[Brief description of the drawings]

FIG. 1 is a view for explaining a resistance welding method of an aluminum-based material in which an insert member is interposed on a joining surface.

FIG. 2 is a view for explaining a method of resistance welding by interposing powder between aluminum plate materials.

FIG. 3 is a diagram for explaining a welding model according to the present invention and a conventional method.

FIG. 4 is a diagram showing a relationship between a nugget diameter and a current in the first embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a nugget thickness and a current in the first embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the particle size and the tensile shear strength after welding in Example 2 of the present invention.

FIG. 7 is a diagram showing a change in a generated nugget diameter when a welding current is changed in Example 2 of the present invention.

FIG. 8 is a diagram showing a relationship between a welding current and a formed nugget diameter in a third embodiment of the present invention.

[Explanation of symbols]

 11, 12: Work 15: Insert member 21, 25: Aluminum plate 22, 24: Oxide film 23: Powder

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tamotsu Harada 1-10-1 Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (56) References JP-A-1-289579 (JP, A) JP-A-64 -53780 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 11/18

Claims (4)

(57) [Claims] 1. A resistance welding method for an aluminum-based material in which an insert member is interposed at a joining surface when the aluminum-based material is resistance-welded, wherein the insert member includes Fe, Ni, Co, Cr,
At least one selected from the group consisting of Ti and a semiconductor material
Is mixed with the semiconductor material at a ratio of 30 to 40% by weight.
By using a powder obtained by applying a mixed solution of the powder, the powder is interposed in the bonding surface,
The oxide film on the surface of the aluminum-based material was removed during energization.
It is, after power is the insert part and the aluminum-based material
The method of resistance welding aluminum-based material, characterized in that the wood is complexed or alloyed. 2. A method according to claim 1, wherein said semiconductor material is SiC.
Resistance welding method for N-based materials. 3. The joining surface during resistance welding of an aluminum-based material.
For resistance welding of aluminum material interposed in steel
The member is selected from the group consisting of Fe, Ni, Co, Cr, Ti
The one or more semiconductor materials and the semiconductor material are 30
Characterized by being mixed at a ratio of up to 40% by weight.
Insert member for resistance welding of aluminum material. (4) The resistance melting of the aluminum material according to claim 3.
In the connecting insert member, Aluminum, wherein the semiconductor material is SiC
Insert member for resistance welding of nickel-based material.