JPH07284955A - Method for resistance welding plated steel material and aluminum base material and clad material - Google Patents

Abstract

PURPOSE:To carry out a high quality welding by applying a high density current between a plated steel material and a clad material in a resistance welding method being suitable to a spot welding between the steel material executing a corrosion preventing treatment, etc., with a plating work and an aluminum base material. CONSTITUTION:The clad material 15 composed of an iron layer 15a having projecting parts 15c and an aluminum layer 15b is interposed between the plated steel plate 13 as a material to be welded and the aluminum steel plate 14. A specified current is applied to the electrodes 10, 11 from AC electric source 15b. Electric conducting passage of the welding current is limited to the area of the projecting parts 15c, and as molten plating metal by melting the plating layer 13a is incorporated among the pitches of the projecting parts 15c, the enlargement of the electric current conducting area is prevented. In this result, the temp. of the interface between the plated steel plate and the clad material is efficiently raised and the suitable nugget is formed to both surfaces of the clad material 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding method of a plated steel material and an aluminum-based material, and a clad material used in the method, and particularly to a steel material and an aluminum-based material which are subjected to rust prevention treatment by plating. The present invention relates to a resistance welding method of a plated steel material and an aluminum-based material suitable for spot welding, and a clad material suitable for use in the method.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of performing resistance welding for joining between dissimilar metals. For example, a plate thickness and a plate thickness ratio are defined between a plate made of a non-aluminum metal and a plate made of an aluminum material. JP-A-5-11177 discloses a method of inserting two layers of non-aluminum / aluminium clad material consisting of a non-aluminum metal plate and an aluminum-based material plate and performing spot welding under a current condition guided by a specific formula.
No. 8 publication.

Regarding a method of spot welding a steel plate and an aluminum plate by using an iron / aluminum two-layer clad material as an insert material, JP-A-4-55066, JP-A-4-127973, and JP-A-4127793 are cited. -253
It is known from Japanese Patent No. 578, etc.

However, these conventional methods have problems in that two-step energization is required and a large current is required. It should be noted that these conventional methods do not consider a method of keeping the strength of the joint high in a wide current range or a method of spot welding a plated steel plate and an aluminum plate. Further, in this dissimilar metal joining method, changing the electrode shape or using projection has not been considered.

[0005]

By the way, in recent years, there have been various demands for joining dissimilar metals. For example, in spot welding of automobile bodies, a steel sheet plated for anticorrosion treatment (hereinafter referred to as "plating"). A technique for resistance welding a steel plate) and an aluminum-based material is required.

In this case, since the base material to be resistance-welded is a steel plate and aluminum, it is similar to the object of the resistance welding method disclosed in the above-mentioned publication, and therefore the above-mentioned between the plated steel plate and the aluminum plate. It is considered that resistance welding is performed with a clad material interposed.

However, when the interface between the plated steel sheet and the clad material is heated by resistance heating, the plating metal forming the plating layer is melted before the nugget grows on both surfaces of the clad material, and as a result, the plated steel sheet and the clad material are clad. The hot-dip plating is interposed between the material and the material, and the energized area is expanded, the current is expanded in this portion, and the current density is reduced.

Therefore, in order to form a nugget capable of ensuring sufficient strength, it is necessary to pass a large amount of current as compared with the case of resistance welding a steel sheet, but when a high current is used, electrode welding and aluminum melting are performed. There was a problem that the current value could not be increased because the metal scattering (dust) was large, and the welding condition range was extremely narrow.

The present invention has been made in view of the above points, and when resistance welding is performed with a clad material interposed between a plated steel material and an aluminum-based material, the contact area between the plated steel material and the clad material is It is an object of the present invention to provide a resistance welding method for a plated steel material and an aluminum-based material, which secures a high current density in the initial stage of energization by reducing the above, and thereby solves the above problems.

[0010]

[Means for Solving the Problems] The above-mentioned object is to make a clad material made by laminating a steel-based metal and an aluminum-based metal between a plated steel material and an aluminum-based material so that the metals of the same series face each other. A resistance welding method of a plated steel material and an aluminum-based material for interposing resistance welding, wherein the plated steel material and the aluminum-based material are formed by reducing an initial energization area formed between the plated steel material and the clad material. It is achieved by the resistance welding method with.

Further, in the resistance welding method of the plated steel material and the aluminum-based material having the above-mentioned structure, unevenness is formed on at least one of the clad material contact surface of the plated steel material and the plated steel material contact surface of the clad material. A configuration that reduces the energizing area is also effective.

Further, in the resistance welding method of the plated steel material and the aluminum-based material having the above-mentioned constitution, the current-carrying area is reduced by interposing a steel-based metal plate having an opening between the plated steel material and the clad material. The configuration is also valid.

In the resistance welding method of the plated steel material and the aluminum-based material having the above-described structure, the clad material formed by laminating the steel-based metal and the aluminum-based metal has a predetermined area ratio of It can be easily carried out by using a clad material having irregularities.

[0014]

In the resistance welding method of the plated steel material and the aluminum-based material according to the present invention, since the contact area between the plated steel material and the clad material is reduced, the plated steel material and the aluminum-based material are When a current flows between the two, a high current density is secured at the beginning of energization. Therefore, the temperature of the interface between the plated steel material and the clad material is efficiently raised, and weld nuggets are appropriately formed on both surfaces of the clad material.

Further, when at least one of the contact surfaces of the plated steel material and the clad material is provided with irregularities to reduce the current-carrying area, when the plated metal on the surface of the plated steel material is melted, the molten plating is Since it fits in the recess, expansion of the current-carrying area due to hot dipping is prevented.

Further, in a structure in which a steel material metal plate having an opening is interposed between the plated steel material and the clad material to reduce the current-carrying area, the plated steel material and the clad material themselves are not special. A reduction in the current-carrying area is realized without processing.

When a clad material having a surface area on the side of the steel-based metal having irregularities formed therein is interposed between the plated steel material and the aluminum-based material, regardless of the position at which resistance welding is performed, the aforesaid A suitable current-carrying area is secured between the plated steel material and the clad material.

[0018]

FIG. 1 is a conceptual diagram for explaining a resistance welding method for a plated steel material and an aluminum material, which is an embodiment of the present invention.

As shown in the figure, an AC power supply 12 is connected to the electrodes 10 and 11. The AC power supply 12 generates an AC voltage having a predetermined cycle and a predetermined voltage for a predetermined period according to a preset condition and supplies the AC voltage to the electrodes 10 and 11.

The electrodes 10, 11 both have a tip diameter of 6
mm, Dome radius type with a tip radius of curvature of 40 mm (DR
(Type) electrode, which can be displaced together with an arm (not shown) to generate a predetermined load therebetween.

The member 13 to be welded with which the electrode 10 abuts is a rust-preventive plated steel plate 13 having a plated layer 13a formed by galvanization on both sides, while the member 14 to be welded abutting with the electrode 11 is an aluminum-based material. It is the configured aluminum plate 14.

Between the plated steel plate 13 and the aluminum plate 14, an iron layer 15a made of an iron-based metal, which is a steel-based metal,
A clad material 15 formed by laminating an aluminum plate 14 and an aluminum layer 15b which is a similar metal is interposed. The iron layer 15a and the aluminum layer 15b are laminated by solid phase bonding such as pressure bonding.

FIG. 2 shows a plan view (FIG. (A)) and a front sectional view (FIG. (B)) of the clad material 15. As shown in FIG. The surface of the iron layer 15a is provided with a plurality of convex portions 15c having a predetermined pitch, a predetermined height, and a predetermined area ratio.

By the way, in the resistance welding adopted as the welding method in the present embodiment, a predetermined load is applied between the metals to be welded, and in that situation, a current is passed to cause resistance heat generation at the metal interface, which is generated. This is a welding method for forming and growing a weld nugget on the boundary surface as a heat source.

In this case, the amount of heat generated by resistance heating is equal to the amount of power consumed by the electrodes 10 and 11, and the amount of heat generated per unit deposition is proportional to the square of the density of the current flowing. Therefore, in order to efficiently raise the temperature of the welded portion for the same power consumption, it is necessary to improve the current density during resistance welding.

On the other hand, in the plated steel plate 13 having the plating layer 13a on the surface, the plating melts during resistance welding, and if no treatment is applied to the hot dip plating, the energized area increases. As described above, it is difficult to secure an appropriate current density.

In this embodiment, the convex portion 1 is formed on the clad material 15.
The reason why 5c is provided is to remove the adverse effects caused by the melting of the plated layer 13a. Specifically, as shown in FIG. 3, a small-area current is applied between the plated steel plate 13 and the clad material 15. This is to form.

That is, according to the resistance welding method of the present embodiment, a predetermined AC voltage is applied between the electrodes 10 and 11 to apply a predetermined current to the plated steel plate 13, the aluminum plate 14, and the clad material 15, which are the objects to be welded. The current-carrying area of the current that is formed when flowing is restricted by the area of the convex portion 15c of the clad material 15.

Therefore, the resistance heat generated by the current flow is
It is concentrated on the contact surface between the convex portion 15c of the clad material 15 and the plated steel plate 13. Further, the hot dip 13b generated by such heat generation is deposited on the surface of the clad material 15 excluding the convex portion 15c, and the contact area between the plated steel sheet 13 and the clad material 15, that is, the area through which the current flows is expanded due to the influence. Never.

Therefore, according to the resistance welding method of the present embodiment, even when the plated steel sheet 13 having the plating layer 13a on the surface thereof is an object to be welded, it is possible to stably form a high current density. It is possible.

Since such a high current density can be formed, the interface between the clad material 15 (iron layer 15a) and the plated steel sheet 13 and the clad material 15 (aluminum layer 15).
Appropriate weld nuggets can be formed at the interface between b) and the plated steel plate 13.

Here, the weight per unit area of the plated steel plate 13 is 60.
/ 60 g / m ² double-sided galvanized steel plate, A5052 (JIS standard) as aluminum plate 14, welding load between electrodes 1.96 kN, welding time 167 ms (10 cycles for 60 Hz AC power supply) 4 to 7 show the results of resistance welding performed by changing the shape and welding current value of 15c and evaluating the weld quality formed by tensile shear strength. In addition, the tensile shear strength shown in each figure is the experimental N in FIG.
It is an average value of n = 2 except the data shown in o.29.

Nos. 1 to 3 and Nos. 4 to 6 in FIG. 4 are data for comparison with the resistance welding method of the present embodiment, and when a steel sheet without the plating layer 13a is used,
And the case of using a steel plate having the plating layer 13a,
It shows the data of the welding test using the clad material 15 having no convex portion 15c.

Comparing these, in the case of a plated steel sheet, the tensile shear strength is lower as a whole than that of a non-plated steel sheet, and this tendency is remarkable especially under a low welding current with a low current density. I understand.

On the other hand, FIGS. 5 to 7 show the height of the convex portions 15c, the area ratio of the convex portions 15c in the clad material 15, and the pitch at which the convex portions 15c are formed by the resistance welding method of this embodiment. The experimental results obtained when the parameters are changed are shown. In each case, good results are obtained as compared with the case where the convex portion 15c is not provided as a whole.

A more detailed analysis shows No. 7 shown in FIG.
~ 9, No.10-12, No.13-15, the convex portion 15
Regarding the height of c, it is understood that the larger the height, the more advantageous it is within 1.0 mm. In such a dimension area,
It can be presumed that the height is high and the storability of the hot dip 13b is excellent, which is advantageous for improving the welding quality. In this sense, the resistance welding method of the present embodiment is 0.05 mm to 1.0 mm.
It is preferable to form the convex portion 15c to some extent.

However, when the plate thickness of the steel plate is thin, the height of the convex portion may be 0.05 mm or less. in this case,
The height of the convex portion is preferably 0.02 to 1.0 mm. Further, more preferably, the height of the convex portion is 0.05 to
It is 0.5 mm.

No. 16-18 and No. 1 shown in FIG.
From Nos. 3 to 15 and Nos. 19 to 21, it can be seen that good welding quality can be secured regardless of the area ratio of the convex portion 15c as long as it is about 20% to 85%. However, when the area ratio of the convex portion 15c is extremely low, the convex portion 15c is deformed by the load applied in the resistance welding process, and when the area ratio is extremely high, the hot dip 13
Since the effect of preventing the enlargement of the energized area cannot be obtained due to the deterioration of the storability of c, it is estimated that the area ratio of about 10% to 90% is appropriate.

No. 22 to 24 and No. 13 to 1 shown in FIG.
Nos. 5, Nos. 25 to 27 and Nos. 28 to 30 show that good effects can be obtained under any of the pitch conditions as long as they are within the condition range of this time.
With respect to the diameter of 11, the upper limit of the pitch is about 3.0 mm.

That is, in FIG. 7, the two data shown in parentheses in No. 29 are the data in which the number of repetitions is 1 (n = 1) without averaging. 7
The kN is comparable to the other conditions, but the strength of the other 1.9 kN is significantly lower than the other conditions.

This result shows that the tips of the electrodes 10 and 11 are hemispherical with a diameter of 6 mm, so that the welding execution position is the convex portion 15.
It is considered that the current could not be concentrated on the specific convex portion 15c between the pitches of c. In this sense, in this embodiment, the pitch is preferably set to 3.0 mm or less in consideration of the dimensions of the electrodes 10 and 11.

As a method of improving the weldability of the steel sheet, there is a method of providing a projection projection on the object to be welded in the pressing process to concentrate the electric current. If this method is applied to resistance welding of the plated steel sheet, Although it is conceivable to provide the projections 17 on the clad material 16 as shown in FIG.
Since it is necessary to catch the projections 17 and perform welding while sandwiching between the plated steel plate 13 and the aluminum plate 14, there is a problem in workability.

On the other hand, in the resistance welding method of the present embodiment, the current concentration can be appropriately concentrated no matter where the electrodes 10, 11 are brought into contact with each other in the region where the clad material 13 is interposed. It is also possible to achieve resistance welding with excellent workability.

In the above-mentioned embodiment, the clad material 15 is provided with the convex portion 15c to prevent the expansion of the current-carrying path formed between the plated steel plate 13 and the clad material 15, but However, the present invention is not limited to this, and the plated steel plate 18 as shown in FIG.
The convex portion 18a may be formed on the side and the clad material 19 may be flat. However, it is more useful to form the convex portion on the clad material side because it is easier to manufacture and can be applied at a lower cost.

Further, the clad material 15 shown in FIG.
Although it is configured to include the prismatic protrusion 15c, the protrusion 15c
Is to reduce the contact area between the plated steel plate 13 and the clad material 15. As long as this function can be realized, the shape is not limited and, for example, as shown in FIG. Clad material 20, FIG. 10 (B)
As shown in FIG. 10, the clad material 21 having the protrusions 21 a in the shape of a triangular prism, or the recess 22 in the shape of a prism as shown in FIG.
The same effect can be obtained by the clad material 22 including a.

The convex portion may have a columnar shape or a shape in which the cross-sectional area decreases toward the tip side. Further, the recess may have a columnar shape or a shape in which the recess cross-sectional area decreases toward the inner side of the recess.

The clad materials 15, 20, 21, 22,
Convex portions or concave portions 15c, 20a, 21 on the plated steel plate 18 or the like
As a method for forming a, 22a, and 18a, an iron layer of a clad material having no unevenness or a plated steel plate is subjected to compression molding of an uneven pattern by, for example, a rolling roller, or a groove is formed by machining, etching, laser processing, or the like. A forming method or the like can be applied.

Further, as shown in FIG. 11, an opening 24a is formed in the clad material (or plated steel plate 13) 23 having no unevenness.
It is possible to apply a method of crimping the net-like steel sheet thin plate 24 having the above or inserting the steel sheet thin plate between the clad material 23 and the plated steel sheet 13 prior to resistance welding. In this case, the clad material 23 and the plated steel plate 13 do not need to be subjected to any uneven processing, and the resistance welding method of this embodiment can be realized very easily.

Further, the above-mentioned embodiment shows an example in which the resistance welding method according to the present invention is applied to spot welding, but the applicable range is not limited to the spot welding shown in the above-mentioned embodiment. For example, as shown in FIG. 12, a pair of rollers 3 having a plurality of corresponding protrusions 31a and 32a.
It is also applicable to roll spot welding in which spot welding is continuously performed using Nos. 1 and 32, seam welding in which an object to be welded is sandwiched between a pair of rollers having no protrusions, and the like.

[0050]

As described above, according to the first aspect of the present invention, it is possible to cause a high-density current to flow between the plated steel material and the clad material, and the position where resistance welding should be performed is locally efficiently performed. The temperature can be raised well. Therefore, the welding nugget can be appropriately grown with a relatively small current, and stable welding strength can be obtained under a relatively wide range of welding conditions.

According to the second aspect of the invention, even if the plating metal on the surface of the plated steel material melts during resistance welding,
Since the hot-dip plating is stored in the concave portion and the contact area between the plated steel material and the clad material is prevented from being enlarged, the above-described effect due to the reduction of the current-carrying area can be stably enjoyed.

Further, according to the invention of claim 3, it is not necessary to make unevenness on the plated steel material and the clad material itself,
A desired effect can be obtained simply by interposing a steel material metal plate having an opening, and resistance welding of a plated steel material and an aluminum material can be performed extremely easily.

According to the invention of claim 4, an appropriate current-carrying area can be secured between the plated steel material and the clad material regardless of the position of resistance welding, and precision is required at the welding position. The desired effect can be obtained without

[Brief description of drawings]

FIG. 1 is a conceptual diagram for explaining a resistance welding method that is an embodiment of the present invention.

FIG. 2 is a configuration diagram of a clad material which is a main part of the present embodiment.

FIG. 3 is a diagram for explaining the effect of the resistance welding method of the present embodiment.

FIG. 4 is a result (1) of an effect confirmation experiment of the resistance welding method of the present embodiment.

FIG. 5 is a result (2) of an effect confirmation experiment of the resistance welding method of the present embodiment.

FIG. 6 is a result (part 3) of an effect confirmation experiment of the resistance welding method of the present embodiment.

FIG. 7 is a result (part 4) of an effect confirmation experiment of the resistance welding method of the present embodiment.

FIG. 8 is a diagram for explaining ancillary effects of the resistance welding method of the present embodiment.

FIG. 9 is a conceptual diagram for explaining another embodiment of the resistance welding method according to the present invention.

FIG. 10 is a configuration diagram of another example of the clad material suitable for the resistance welding method of the present embodiment.

FIG. 11 is a constitutional view of another example of the clad material suitable for the resistance welding method of the present embodiment.

FIG. 12 is a diagram for explaining an application example of the resistance welding method according to the present invention.

[Explanation of symbols]

 10, 11 Electrode 13, 18 Plated steel plate 14 Aluminum plate 15, 20, 21, 22 Clad material 15a Iron layer 15b Aluminum layer 15c, 18a, 20a, 21a Convex portion 22a Recessed portion 24 Steel sheet thin plate 24a Opening portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsutoshi Ueno 1 Toyota-cho, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Fuminori Matsuda 1-cho, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. ( 72) Inventor Goro Watanabe, Toyota Central Research Institute Co., Ltd. 1 at 41 Yokomichi, Nagakute-cho, Aichi-gun, Aichi-gun (72) Inventor, Hatsuhiko Oikawa 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Co., Ltd. Headquarters (72) Inventor Hiroshi Okuda 1-24 South Meieki Minami, Nakamura-ku, Aichi Prefecture Nagoya 30-23 Nippon Steel Co., Ltd.Nagoya Branch (72) Inventor Kazuo Narita 1-chome, Minamieki, Nakamura-ku, Aichi Prefecture Nagoya 24-30 Nagoya Branch of Nippon Steel Corporation

Claims (4)

[Claims] 1. A clad material formed by laminating a steel-based metal and an aluminum-based metal between a plated steel material and an aluminum-based material,
A resistance welding method of a plated steel material and an aluminum-based material in which resistance welding is performed by interposing similar metals so as to face each other, wherein an energization area formed between the plated steel material and the clad material is reduced. A resistance welding method for a plated steel material and an aluminum-based material. 2. The resistance welding method of a plated steel material and an aluminum-based material according to claim 1, wherein unevenness is formed on at least one of a clad material contact surface of the plated steel material and a plated steel material contact surface of the clad material. A resistance welding method between a plated steel material and an aluminum-based material, which is characterized by reducing the energizing area. 3. The resistance welding method of a plated steel material and an aluminum material according to claim 1, wherein a steel material metal plate having an opening is interposed between the plated steel material and the clad material to increase an energization area. A resistance welding method for a plated steel material and an aluminum material, which is characterized by being reduced. 4. A clad material formed by laminating a steel-based metal and an aluminum-based metal, wherein the steel-based metal-side surface is provided with irregularities having a predetermined area ratio.