JP2744750B2 - Insert material for resistance welding of aluminum and aluminum alloy materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is to improve the electrode life in the case of aluminum and an aluminum alloy having a lower electrode life in resistance welding than in the case of a rolled steel sheet, and to improve the electrode life as well as the case of a rolled steel sheet. The present invention relates to an insert material for making the indentation of the insert inconspicuous.

[0002]

2. Description of the Related Art A resistance spot welding method has been widely used as a joining method in an assembly process in mass production of automobiles or the like using a conventional rolled steel sheet.
Because it is a very efficient welding method, suitable for mass production, and once the welding conditions are set, it can be easily welded even by a completely novice person or even by a robot, and stable welding nuggets and joint strength can be obtained. is there. In the conventional resistance spot welding method, materials to be welded are overlapped, pressurized and energized by an upper electrode and a lower electrode to form a nugget and join. Not only the conventional rolled steel sheet, but also in the case of resistance spot welding of aluminum and its alloys and composite materials, the first or second JIS Z ^3234-1977 “electrode material for resistance welding” as an electrode material. In general, a seed is used, and the shape of the electrode is a shape determined by JIS C ^9304-1986 “Shape and dimensions of spot welding electrode”. The reason why these materials are used as the electrode material is that the electrode and the material to be welded are hard to be joined at the contact portion because they have higher thermal conductivity and conductivity than the material to be welded, so that they can be continuously welded.

However, in practice, the number of welding points (electrode life) that can be continuously welded while ensuring required performance such as predetermined strength and nugget diameter differs depending on the type of material to be welded. Before welding, the tip of the electrode is cut into a predetermined shape or polished to a predetermined surface roughness to prepare the electrode. This is called dressing. The number of hit points at which a weld having the required performance is continuously obtained by one dressing is referred to as the electrode life of the electrode. The number of continuous hits until the nugget diameter or tensile shear strength falls below the specified value. At the tip of the electrode, an alloy layer of the electrode and the material to be welded is formed,
The phenomenon in which the appearance is impaired by being transferred to the welded portion is referred to as pickup, and the number of continuous hitting points before the start of occurrence. It is the number of continuous hits before the phenomenon in which the electrode is welded to the material to be welded and cannot be removed occurs. The normal electrode life is determined by the above method of determining + or ++. So ++
It is said that the electrode life of resistance spot welding on an assembly line of an automobile using a conventional rolled steel sheet is 10,000 points or more according to the judgment method described above. As described above, the resistance spot welding of a rolled steel sheet has a very long electrode life. On the other hand, the electrode life of the resistance spot welding of aluminum and aluminum alloy is said to be 30 to 100 points, but 200 to 10 is given in the case of + not evaluated.
00 points.

[0004] As described above, the electrode life in resistance spot welding of an aluminum alloy is much inferior to that of a rolled steel sheet, and methods for improving the electrode life have been conventionally studied. For example, Japanese Unexamined Patent Publication No. 61-159288 discloses that when aluminum or an aluminum alloy is subjected to electric resistance welding, an insert material (foil-like inclusion, using pure copper) having higher electric conductivity than the electrode is provided between the electrode and the material to be welded. There is a method of interposing and welding. This means that even when welding with
This is a method of welding aluminum alloys without penetrating to the surface of the plate and without generating surface cracks, and is considered to have the effect of improving the electrode life to some extent.

[0005] In resistance welding of aluminum and aluminum alloy, when copper and copper alloy (excluding Cu-Zn alloy) foil are used between the electrode and the material to be welded, the affinity with aluminum is high. It is easy to perform diffusion bonding at around 200 ° C. where pressure and welding are performed. For this reason, it turned out that it is unsuitable as an insert material (inclusion) for resistance welding, despite being conductive and having a higher melting point than aluminum. On the other hand, from the viewpoint of energy saving, it is desired to reduce the weight of automobiles, and aluminum and aluminum alloys that are light and high in strength have attracted attention as automotive materials. However, as described above, resistance welding of aluminum and aluminum alloys has a remarkably short electrode life as compared with conventional rolled steel sheets, and the dressing of the electrodes becomes frequent. This becomes a bottleneck in mass production of automobiles and the like. there were. In addition, when the electrode tip is worn and irregularities occur, imprint marks of the electrode remain ugly on the work to be welded, which is a problem in places where appearance is important.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of studying the above-mentioned problems, and in the resistance welding of aluminum and aluminum alloy, the life of the electrode is remarkably improved and an insert in which the impression of the electrode is inconspicuous. The material was developed.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a Zn3-60
%, A Cu-Zn alloy consisting of the balance Cu
Claim 1 is an insert material for resistance welding of aluminum and an aluminum alloy material as a foil plate having a thickness of ~ 1 mm, wherein a diffusion layer of a Cu-Zn alloy of 3 to 60 wt% Zn is provided on a surface of a Cu plate, and a thickness of 0.02 mm is provided. An insert material for resistance welding of aluminum and an aluminum alloy material, which is a foil plate having a thickness of 1 mm or less, is defined as claim 2.

[0008]

That is, according to the present invention, as a result of intensive studies on the insert material, the insert material contains 3 to 60% by weight of Zn and the balance C
alloy consisting of u and unavoidable impurities, thickness 0.02 to 1 m
m of a foil-like plate, and 3-60% by weight of Cu-Z
Copper plate with n alloy diffused on the surface of the plate.
When welding is performed with an insert material of a 1 mm foil plate interposed between the upper and lower electrodes and the material to be welded, the C
The insert material such as u has no affinity with the electrode and aluminum and aluminum alloy, so the electrode life is long, and there is no welding to the electrode and the work to be welded. It has also been found that good appearance and internal quality of the part can be welded.
If the content of Zn is less than 3% by weight, welding occurs between the insert material and the workpiece, and if it exceeds 60% by weight, welding to the electrode becomes easy. Therefore, Zn is set to 3 to 60% by weight. If the thickness of the insert material is less than 0.02 mm, it will be easily welded during welding, impeding continuous welding, and if it exceeds 1 mm, the current loss and cooling effect of the insert material will be too large to inhibit the formation of the weld nugget and the strength will be reduced. In addition, when the tape is continuously supplied in the form of a tape, problems are likely to occur. Therefore, the thickness of the insert material is 0.02-1 m
m. Further, the insert material of the present invention is Cu-Z
The same effect can be obtained by providing a diffusion layer of n alloy. Cu
As a method of providing a diffusion layer of a Zn alloy, Zn or a Cu-Zn alloy is usually formed on the surface of a Cu plate by ordinary electroplating, vacuum deposition, or the like, and is easily formed by heating and diffusing the same. it can. The depth of this diffusion layer is
The thickness is preferably about 1/2 to 1/200 of the thickness of the insert material. It is necessary to perform Zn diffusion on both sides of the Cu plate in order to make the electrode life and indentation inconspicuous, but even if it is performed on one side, the Zn diffused surface hits the aluminum alloy side which is the material to be welded. When used in this way, there is some effect.

The insert material is cut into a suitable size before welding, and is placed or adhered to the welded portion of the work to be welded. The insert material is sandwiched between electrodes and welded, and the nugget is removed by welding. A weld with a healthy diameter and indented surface is obtained. By repeating this process, a welded portion in which all the nuggets and the indented surface are sound can be continuously obtained, the consumption of the electrode is extremely small, and the life of the electrode is remarkably improved. Further, the insert material is formed in a ribbon shape (tape shape) and supplied to the welded portion at one point or every several points, so that continuous hitting becomes possible, and welding can be performed efficiently. The present invention relates to aluminum and aluminum alloys, for example, aluminum alloys such as Al-S
i-based, Al-Mg based, Al-Mg-Si based, Al-Cu
-It can be applied to resistance welding of alloy materials such as Mg-based and Al-Zn-Mg-Cu-based. The welding machines used for this welding are conventional single-phase AC resistance welding machines, single-phase rectification resistance welding machines, three-phase low-frequency resistance welding machines, three-phase rectification resistance welding machines, and condenser-type resistance welding machines. Any of a welding machine and an inverter resistance welding machine may be used. Also, the insert material can be automatically and continuously supplied.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. (Embodiment 1) FIG. 1 is a schematic view showing Embodiment 1 of the present invention. The upper electrode 5 and the lower electrode 6 are JIS Z3234-2
16 mmφ of chromium copper corresponding to the seed was used, the electrode tip shape was a DR type, and the tip 6 mmφ was R = 40 mm. Holes 7 and 8 having a diameter of 9 mm for cooling were drilled in the electrodes, and waters 11 and 12 were passed through conduits 9 and 10 at a flow rate of 4 l (liter) / min to cool the electrodes. Materials to be welded 3, 4 are Al-Mg based alloy 5182-0 material, 1 m
The thickness of the material between the upper electrode 5 and the material 3 to be welded and between the lower electrode 6 and the material 4 to be welded.
Of the insert materials 1 and 2, the comparative insert material, and the conventional copper foil insert material, using a single-phase AC welding machine, a welding current of 23000 A and an electrode pressing force of 2940.
N, welding was performed under welding conditions of 5 cycles of energization time. In addition,
The material to be welded is in a surface state as received, and the dimensions of the test piece are 30 × 200 mm.
Welded at five pitches. The insert material was cut to the same dimensions as the material to be welded, and was sandwiched between the electrode and the object to be welded. Each test was replaced with a new electrode, and 15,000 continuous welding was performed.

The size of the nugget diameter is determined by sandwiching one end of the material 3 to be welded in the peel test jig 18 of FIG. 3, peeling it off while rounding it, and measuring the long and short diameters of the nugget 13 with calipers. Was calculated. Nugget diameter = (long diameter + short diameter) / 2 (mm) Limit of electrode life Nugget diameter is JIS Z 3140
The minimum nugget diameter of Class A was 4 mm. The welding was evaluated as follows. * Method of evaluation method: Number of dots when nugget diameter is less than 4 mmφ Method: Number of dots when electrode, material and insert material are welded, or electrode and insert or insert and welded material are welded Method: Pickup Number of hits when appearance and poor appearance ** Comprehensive judgment (by ++ or +) ◎ Electrode life is 15,000 points or more ▲ Electrode life is 10,000 points or more and less than 15,000 points × Electrode life is less than 10,000 points These results Are shown in Table 1.

[0012]

[Table 1]

As is clear from Table 1, the present invention examples No. 1 to N
In the case of o.9, all of them could be welded at 15,000 points, there was no welding of the insert material to the workpiece or the electrode, and all the nugget diameters were 4 mm or more. That is, the electrode life was 15,000 points (or more). The state of the electrode tip at this time was examined using pressure-sensitive paper.
After welding at 000 points, the shape of the electrode tip was almost unchanged. On the other hand, No. 10 and No. 12 of the comparative examples have thinner insert materials, No. 11 and No. 13 are thicker, and No. 1
4, No15 has a small amount of Zn and No, 16 and No17 have a large amount.
The electrode life did not reach 10,000 points due to welding with the material to be welded or a nugget diameter of 4 mm or less.
In addition, the conventional example of No. 18, No.
The electrode life was 500 points, and the electrode life was 785 points when welding was performed without using the No. 20, foil-shaped inclusion. (The nugget diameter became smaller than the standard.) The electrode tip shape at that time was the 33rd point, and the center of both the upper and lower electrodes was already concave, and the appearance was poor. As described above, according to the present invention, the electrode life is at least 2 to 20 times that of the comparative example and the conventional example.

(Embodiment 2) FIG. 2 is a schematic view showing Embodiment 2 of the present invention. Upper electrode and lower electrode 6 are JISZ32
A chromium-zirconium-copper alloy of 16 mmφ corresponding to two kinds of 34 was used.
0 mm. Holes 7 and 8 of 9 mmφ for cooling are provided on the electrodes.
And 4 liters of water 11, 12 through conduits 9, 10
The electrode was cooled by flowing at a flow rate of (liter) / min. The materials to be welded 3, 4 are Al-Mg based alloys 5052-0.
Material, 1 mm thick material, upper electrode 5 and welded material 3
Between the lower electrode 6 and the material 4 to be welded, using the single-phase rectifying resistance welding machine with the insert materials 1 and 2 of claim 2 of the present invention interposed therebetween, welding current 25000 A, electrode pressing force 2
Welding was performed under the welding conditions of 940 N and 5 cycles of energization time.
In addition, the material to be welded is in the surface state as received, the dimensions of the test piece are 30 × 200 mm,
Five points were welded at 0 mm pitch. Insert material is 16m
It was made into a tape having a width of m, and was automatically supplied between the electrodes and the material to be welded by the feed reels 14 and 15 and the take-up reels 16 and 17 for welding. Electrodes are # 10 before starting welding for each material
Dressed with 00 emery paper. Then, 15,000 continuous welding was performed. Evaluation of the welded test piece is the same as in Example 1. As a comparative example, welding was carried out in the same manner as described above using eight kinds of components and thicknesses deviating from the material of the present invention. In addition, as a conventional method, the electrode life was examined for a case where a Cu simple metal foil was used and a case where welding was performed under the same conditions without using a foil-like inclusion. Table 2 shows the results.

[0015]

[Table 2]

As is clear from Table 2, Nos. 1 to
No. 9 could be welded at 15,000 points, all had a nugget diameter of 4 mm or more, and had good appearance. That is, the electrode life was 15,000 points (or more).
At this time, the state of the electrode tip was examined using a pressure-sensitive paper, and the shape of the electrode tip hardly changed before the start of welding and after welding at 52,000 points. In contrast, No. 10
No.12 and No.12 have a small depth and thickness of the diffusion phase of the insert material, No.11 and No.13 have a small depth and a large thickness, and No.14 and No.1 have a low Zn content. No. 16 and No. 17 had a large amount of Zn because of their small depth, and the electrode life was less than 10000 because of their small depth. In addition, 1300 to 5200 points were obtained for Cu Nos. 18 and No. 19 in the conventional example. Further, the electrode life was 501 points when the welding was performed without using the No. 20 foil-shaped inclusion. (The nugget diameter became smaller than the standard.) At that time, the electrode tip shape was at the fifteenth point, and the center of both the upper and lower electrodes was already concave, and the appearance of the indentation was poor.

[0017]

As described above, the insert material of the present invention has a sufficient nugget diameter and a good indentation surface for resistance welding of aluminum and aluminum alloy materials to electrodes and materials to be welded. None, 150 consecutive
An electrode equivalent to that obtained by welding a rolled steel sheet can be obtained with a score of 00 or more, and greatly contributes to the improvement of resistance welding, which has been the biggest bottleneck in aluminum conversion of automobiles.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a resistance welding situation according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a resistance welding situation according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a peel test situation in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper electrode side insert material 2 Lower electrode side insert material 3 Upper electrode side weldable material 4 Lower electrode side weldable material 5 Upper electrode 6 Lower electrode 7 Upper electrode cooling hole 8 Lower electrode cooling hole 9 Upper electrode cooling water 10 Lower electrode cooling water conduit 11 Upper electrode cooling water 12 Lower electrode cooling water 13 Nugget 14 Upper electrode side feed reel 15 Lower electrode side feed reel 16 Upper electrode side take-up reel 17 Lower electrode side take-up reel 18 peel test jig

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nao Orishi 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (56) References JP-A-5-228642 (JP, A) JP-A Heisei 4-322886 (JP, A) JP-A-61-42496 (JP, A) JP-A-5-318136 (JP, A) JP-A-61-159288 (JP, A) JP-A-4-356371 (JP, A) A) Actual opening Hei 5-53782 (JP, U)

Claims (2)

(57) [Claims] 1. An insert material for resistance welding of aluminum and an aluminum alloy material, which is a foil plate having a thickness of 0.02 to 1 mm made of a Cu—Zn alloy consisting of 3 to 60% by weight of Zn and the balance of Cu. 2. The method according to claim 1, wherein the surface of the Cu plate has a Zn content of 3 to 60% by weight.
An insert material for resistance welding of aluminum and an aluminum alloy material provided with a diffusion layer of a u-Zn alloy and serving as a foil-like plate having a thickness of 0.02 to 1 mm.