JPH06179082A - Double action type resistance spot welding electrodes - Google Patents

Abstract

PURPOSE:To improve the service life of the electrodes to perform spot welding on a plated steel sheet, aluminum and an aluminum alloy or material with aluminum and the aluminum alloy plated. CONSTITUTION:The double acting type resistance spot welding electrodes are composed of inside electrodes 10 and 12 with electric conduction of a core part as a main purpose and outside electrodes 11 and 13 with pressurization as a main purpose formed around those and the inside electrodes are made of metal having electric conductivity >=75 (IACS%). Further, the diameter thereof is made 2.5sq. rt. t (wherein (t) = thickness mm of materials to be welded), the outside electrodes are made of metal having electric conductivity lower by >=40 (IACS%) than the inside electrodes and having the melting point higher than the materials to be welded and gaps are provided between the inside electrodes and the outside electrodes and these are made movable mutually.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、圧延鋼板に比べて電極
寿命の劣るめっき鋼板、アルミニウム及びアルミニウム
合金とその金属めっき材を被溶接材料とする場合に、電
極寿命を飛躍的に改善する複動型抵抗スポット溶接用電
極に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a compound for dramatically improving the electrode life when a plated steel sheet having a shorter electrode life than a rolled steel sheet, aluminum and an aluminum alloy and its metal plated material are used as the materials to be welded. The present invention relates to a dynamic resistance spot welding electrode.

【０００２】[0002]

【従来の技術】従来からめっき鋼板、アルミニウム及び
アルミニウム合金とその金属めっき材料の抵抗スポット
溶接に用いられている電極材料は、比較的、高温強度が
高く、電気伝導度、熱伝導が良好で、比較的低コストで
あるクロム銅、クロム−ジルコニウム銅、及びアルミナ
分散銅等が用いられている。又、スポット溶接用電極形
状としては、Ｒ形、ＤＲ形、ＣＦ形、ピンプル形等が多
く使用されている。これらの電極は、全て溶接に必要な
電気を流す働きと、加圧する働きを１本の電極で行って
いた。2. Description of the Related Art Electrode materials conventionally used for resistance spot welding of plated steel sheets, aluminum and aluminum alloys and their metal plating materials have relatively high high-temperature strength, good electrical conductivity, and good thermal conductivity. Chrome copper, chromium-zirconium copper, and alumina-dispersed copper, which are relatively low in cost, are used. Further, as the electrode shape for spot welding, R type, DR type, CF type, pimple type, etc. are often used. All of these electrodes perform the function of supplying electricity necessary for welding and the function of pressurizing with one electrode.

【０００３】これらの電極を用いて適正溶接条件で２枚
の板を重ねて抵抗スポット溶接した場合、図４に示すご
とく初期の頃はナゲット５（２枚の板が抵抗発熱で溶融
し、加圧により接合した部分）は、碁石状で、電極１，
２の径の範囲内で形成し、チリの発生がなく、継手の強
度も高いが、電極と被溶接材料が合金化して電極先端が
消耗してくると図５の様にナゲット５は偏ってきて、電
極径の外まで溶けて、中チリ８、外チリ７が発生して、
著しい場合は、ナゲット内の溶融金属がほとんどチリと
なって飛散し、空洞９になってしまい、継手の強度が低
下して、電極寿命に至る。When two electrodes are overlapped and resistance spot welded using these electrodes under proper welding conditions, as shown in FIG. 4, the nugget 5 (two plates are melted by resistance heat generation and added The part joined by pressure) is in the shape of a go stone,
It is formed within the range of the diameter of 2, there is no dust generation, and the strength of the joint is high, but when the electrode and the material to be welded are alloyed and the tip of the electrode is consumed, the nugget 5 becomes uneven as shown in FIG. Then, it melts to the outside of the electrode diameter, and middle dust 8 and outer dust 7 are generated,
In a remarkable case, most of the molten metal in the nugget becomes dust and scatters to form cavities 9, which lowers the strength of the joint and extends the life of the electrode.

【０００４】溶接初期の場合は、電極の消耗が無いた
め、電極の中心で通電し、その直下の板間の抵抗発熱で
材料同士が溶けて碁石状のナゲットが形成される。溶け
たナゲットは電極の加圧によって、電極直下の２枚の板
の間の電極外周部近傍に形成されるリング状のコロナボ
ンド域６（拡散接合されていて溶融金属を外に出るのを
防ぐと言われている）で囲まれているため飛びださず良
好なナゲットを形成する。In the initial stage of welding, since the electrodes are not consumed, electricity is applied at the center of the electrodes, and resistance heating between the plates directly below the electrodes melts the materials to form a gobstone-shaped nugget. The molten nugget is a ring-shaped corona bond region 6 (diffusion-bonded that prevents molten metal from leaking outside) formed near the outer circumference of the electrode between the two plates directly below the electrode by pressing the electrode. It is surrounded by () and forms a good nugget without jumping out.

【０００５】しかし、電極が消耗して電極の外周部で通
電が起こると、コロナボンド域外でナゲットが形成する
ため、コロナボンドで溶融金属を覆っておく機能が無く
なりチリが発生し、ナゲットが空洞化して強度が低下す
る。従来の電極では電極寿命は、めっき鋼板の場合は、
３０００〜５０００点、アルミニウム及びアルミニウム
合金の場合は３０〜１０００点程度、又、その表面に金
属めっきした材料はそれ以下であると言われている。自
動車産業では、圧延鋼板を用いてスポット溶接を行って
いるが、その電極寿命は、１００００点以上である。そ
れに比較すると、上記従来のめっき鋼板の電極寿命は３
０００〜５０００点、アルミニウム及びアルミニウム合
金は３０〜１０００点、その金属めっき材料はそれ以下
であり、著しく劣る。However, when the electrode is consumed and current is applied to the outer periphery of the electrode, a nugget is formed outside the corona bond region, so that the function of covering the molten metal with the corona bond is lost and dust is generated and the nugget is hollow. And the strength decreases. With conventional electrodes, the electrode life is
It is said that the number is 3000 to 5000 points, about 30 to 1000 points in the case of aluminum and aluminum alloys, and the number of the metal-plated materials is less than that. In the automobile industry, spot welding is performed using rolled steel sheets, and the electrode life is 10,000 points or more. Compared with that, the electrode life of the conventional plated steel sheet is 3
000 to 5,000 points, aluminum and aluminum alloys have 30 to 1,000 points, and the metal plating material has less than that, which is extremely inferior.

【０００６】電極寿命の改善方法としては、従来から多
く検討されているが、中でも多くの研究者によって提唱
されているものは、芯材に融点、硬度が高い材料を用
い、外側に導電性が良好な材料や比較的高い強度と靱性
のある材料を用いる方法である。例えば、特開昭４７−
２３４２６号、特開昭４９−１０６４５６号その他の公
報で知られている。しかし、これらの電極を用いてスポ
ット溶接を行っても、芯材の溶接時の発熱が大きく、被
溶接材料と合金化し、溶着を起こした。又、電極の外周
部の導電性が良好な所で通電するためコロナボンド外で
ナゲットが形成されるためチリが発生して実際には寿命
改善効果は少なかった。[0006] As a method for improving the life of the electrode, many studies have hitherto been made. Among them, the one proposed by many researchers is to use a material having a high melting point and hardness as a core material and to have conductivity outside. This is a method of using a good material or a material having relatively high strength and toughness. For example, JP-A-47-
No. 23426, JP-A-49-106456 and other publications. However, even when spot welding was performed using these electrodes, the heat generated during welding of the core material was large, and the core material was alloyed with the material to be welded and welded. In addition, since electricity is applied where the conductivity of the outer periphery of the electrode is good, a nugget is formed outside the corona bond, and dust is generated, and the life shortening effect is actually small.

【０００７】上記方法とは逆に、芯材として導電性の良
好な材料を用い、外側に非導電性又は耐摩耗性の材料を
用いて安定した溶接部を得る方法も考えられている。例
えば特公昭４５−３０５８０号、特公昭４６−９００号
公報等がある。この場合は、芯材の所で通電し、外周部
の非導電性又は耐摩耗性材料で加圧してコロナボンドを
形成し、ナゲットの溶融金属を覆う効果が得られると考
えられるが、実際には、非導電性のセラミックや耐摩耗
性の超硬合金が加圧時に割れてしまい寿命を改善する効
果が少なかった。Contrary to the above method, a method of obtaining a stable weld portion by using a material having good conductivity as a core material and using a non-conductive or wear resistant material on the outside has been considered. For example, there are Japanese Patent Publication No. 45-30580 and Japanese Patent Publication No. 46-900. In this case, it is considered that the effect of covering the molten metal of the nugget is obtained by applying current at the core material and forming a corona bond by applying pressure with the non-conductive or wear-resistant material of the outer peripheral portion, Had a small effect of improving the life because the non-conductive ceramic and the wear-resistant cemented carbide were cracked when pressed.

【０００８】自動車業界では、省エネルギーや地球環境
の観点から、自動車の軽量化が望まれ、アルミニウム及
びアルミニウム合金、及びそれらに金属めっきを施した
材料が自動車用材料として注目されているが、前述した
ようにそれらの材料の電極寿命は圧延鋼板に比べて著し
く劣るため、これがネックになっていた。少なくとも現
在のめっき鋼板の電極寿命程度の４０００〜５０００点
以上の電極寿命が望まれている。又、自動車の耐食性向
上、高級化指向により、外板にめっき鋼板が使われてい
るが、やはり圧延鋼板に比べて電極寿命が劣るため、圧
延鋼板並の１００００点以上の電極寿命が望まれてい
た。しかし、従来の電極では、それらの電極寿命を前述
のごとく改善することは困難であった。In the automobile industry, from the viewpoint of energy saving and global environment, weight reduction of automobiles is desired, and aluminum and aluminum alloys and materials obtained by metal plating of these are attracting attention as automobile materials. As described above, the electrode life of these materials is remarkably inferior to that of the rolled steel sheet, which is a bottleneck. At least an electrode life of 4000 to 5000 points, which is about the current electrode life of plated steel sheets, is desired. In addition, a plated steel sheet is used for the outer plate in order to improve the corrosion resistance of automobiles and increase in quality. However, since the electrode life is still inferior to that of the rolled steel sheet, an electrode life of 10,000 points or more comparable to that of the rolled steel sheet is desired. It was However, it has been difficult for the conventional electrodes to improve their service lives as described above.

【０００９】[0009]

【発明が解決しようとする課題】本発明は、上記の問題
についての検討の結果なされたもので、めっき鋼板、ア
ルミニウム及びアルミニウム合金とそれらの表面に金属
めっきを施した材料の抵抗スポット溶接にあたり、電極
寿命を飛躍的に向上させる電極を開発したものである。DISCLOSURE OF THE INVENTION The present invention has been made as a result of studies on the above-mentioned problems, and in resistance spot welding of plated steel sheets, aluminum and aluminum alloys and their metal-plated materials, We have developed an electrode that dramatically improves the life of the electrode.

【００１０】[0010]

【課題を解決するための手段】本発明は芯部の電気伝導
を主目的とする内側電極と、その周囲に加圧を主目的と
する外側電極を形成し、該内側電極として導電率が７５
（ＩＡＣＳ％）以上の金属からなり、且つ、その直径を
２．５√ｔ（但しｔ＝被溶接材料の板厚mm）とし、前記
外側電極として、導電率が内側電極よりも４０（ＩＡＣ
Ｓ％）以上低く、かつその融点が被溶接材料より高い金
属からなり、前記内側電極と外側電極との間に隙間を有
し、相互に可動することを特徴とする複動型抵抗スポッ
ト溶接用電極を請求項１とし、前記内側電極の材質は、
９９．９％Ｃｕ、Ｃｕ−１％Ｃｒ、Ｃｕ−１％Ｃｒ−
０．２Ｚｒ、１％アルミナ分散銅、Ｃｕ−２％Ｂｅ、９
９．９％Ｔｉであることを特徴とする請求項１記載の複
動型抵抗スポット溶接用電極を請求項２とし、前記の外
側電極の材質は、９９．９％Ｆｅ、１８−８ステンレ
ス、９９．９％Ｔｉ、９９．９％Ｎｉ、Ｎｉ合金（アル
メル）、９９．９％Ｍｏ、９９．９％Ｗ、Ｃｕ−１０％
Ｚｎであることを特徴とする請求項１記載の複動型抵抗
スポット溶接用電極を請求項３とするものである。すな
わち本発明は、電極を二重構造とし、内側電極を導電性
の高い材料とし、外側電極に導電性の低い材料を用い、
かつ内側電極と外側電極との間に隙間を設けて、内側電
極と外側電極が相互に可動できる複動型にしたものであ
る。According to the present invention, an inner electrode whose main purpose is electric conduction of a core and an outer electrode whose main purpose is pressurization are formed around the inner electrode, and the inner electrode has a conductivity of 75.
(IACS%) or more, and its diameter is 2.5√t (where t = plate thickness mm of the material to be welded), and the conductivity of the outer electrode is 40 (IAC) than that of the inner electrode.
For double-acting resistance spot welding, characterized by being made of a metal having a melting point higher than that of the material to be welded, having a gap between the inner electrode and the outer electrode, and being movable with respect to each other. The electrode is claim 1, and the material of the inner electrode is
99.9% Cu, Cu-1% Cr, Cu-1% Cr-
0.2Zr, 1% alumina dispersed copper, Cu-2% Be, 9
The double-acting resistance spot welding electrode according to claim 1, wherein the outer electrode is made of 99.9% Fe, 18-8 stainless steel, 99.9% Ti, 99.9% Ni, Ni alloy (alumel), 99.9% Mo, 99.9% W, Cu-10%
The double-action resistance spot welding electrode according to claim 1 is Zn. That is, the present invention, the electrode has a double structure, the inner electrode is a highly conductive material, the outer electrode is a low conductive material,
In addition, a gap is provided between the inner electrode and the outer electrode so that the inner electrode and the outer electrode are movable with respect to each other.

【００１１】[0011]

【作用】電極を複動型にした理由は、従来の芯材が導電
性の材料で、外周が通電性の悪い材料を用いた一体型の
電極では、通電部の芯材が溶接中に、被溶接材のアルミ
ニウム合金と合金化して消耗し、外周の材料のみ残っ
て、最終的には先端が凹形になり、通電しにくくなり溶
接できない状態になる。本発明の電極は消耗していく内
側電極と、消耗しにくい外側電極を分離して、別々に可
動することにより、常に、被溶接材料と内側電極及び外
側電極が接触し、両者の働きが、常に溶接開始時点と同
じ様にすることにより電極寿命を向上させたものであ
る。本発明において、内側電極の導電率を７５（ＩＡＣ
Ｓ％）以上に定めた理由は、それ未満では電極が加熱し
て合金化し易く電極寿命の改善効果が少ないことによ
る。また外側電極の導電率を内側電極より４０（ＩＡＣ
Ｓ％）以上低くしなければならない理由は、その値より
導電率が高い場合は、溶接時に被覆材の外周部で通電し
てナゲットが電極接触部より外側に形成し、電極の加圧
力でナゲット内部の溶融している金属を押さえておくコ
ロナボンド域が破れて、そこから溶融金属が飛びだして
チリとなり、ナゲットの空洞化を起こし、強度低下を招
き電極寿命を短くするからである。[Function] The reason why the electrode is the double-acting type is that the conventional core material is a conductive material and the outer periphery is made of a material with poor electrical conductivity. The material to be welded is consumed by alloying with the aluminum alloy, and only the material on the outer periphery remains, and finally the tip has a concave shape, which makes it difficult to conduct electricity and makes it impossible to weld. The electrode of the present invention separates the inner electrode that is consumed and the outer electrode that is less likely to be worn, and by moving them separately, the material to be welded is always in contact with the inner electrode and the outer electrode, and the functions of both are The life of the electrode is improved by always making it the same as when welding was started. In the present invention, the conductivity of the inner electrode is 75 (IAC
S%) or more, the reason is that if it is less than that, the electrode is easily heated and alloyed, and the effect of improving the life of the electrode is small. The conductivity of the outer electrode is 40 (IAC
The reason why the nugget must be made lower than the S%) is that when the conductivity is higher than that value, the nugget is formed outside the electrode contact part by energizing at the outer peripheral part of the coating material during welding, and the nugget is pressed by the electrode. This is because the corona bond area that holds the molten metal inside is broken, and the molten metal jumps out from there and becomes dust, causing the nugget to become hollow, reducing the strength, and shortening the electrode life.

【００１２】そして外側電極の融点を被溶接材料より高
くした理由は、融点がそれらより低いと溶けて合金化し
易いためである。尚、被溶接材料がめっき材料の場合
は、めっき材の融点より高くする。さらに内側電極の先
端径を２．５√ｔ（但しｔ＝被溶接材料の板厚mm）以上
とした理由は、それ未満では、それに適した溶接条件で
溶接するとナゲット径が小さくて、電極寿命が短くな
り、ナゲット径を大きくするような溶接条件で溶接する
と電極の消耗が激しいからである。The reason why the melting point of the outer electrode is set higher than that of the material to be welded is that if the melting point is lower than these, it is likely to melt and alloy. When the material to be welded is a plating material, it is higher than the melting point of the plating material. Furthermore, the reason for setting the tip diameter of the inner electrode to 2.5√t (where t = plate thickness mm of the material to be welded) or more is that if it is less than that, the nugget diameter will be small if welding is performed under suitable welding conditions, and the electrode life will be reduced. This is because when the welding is performed under welding conditions such that the length becomes short and the nugget diameter is made large, the electrode is consumed greatly.

【００１３】本発明の電極を用いて溶接できる材料とし
ては、アルミニウム又はアルミニウム合金、例えばアル
ミニウム合金として、Ａｌ−Ｃｕ系、Ａｌ−Ｍｎ系、Ａ
ｌ−Ｓｉ系、Ａｌ−Ｍｇ系、Ａｌ−Ｍｇ−Ｃｕ系、Ａｌ
−Ｍｇ−Ｓｉ系、Ａｌ−Ｚｎ−Ｍｇ系、Ａｌ−Ｚｎ−Ｍ
ｇ−Ｃｕ系等の合金材料を始め、上記のアルミニウム又
はアルミニウム合金の表面にＺｎ、Ｚｎ−Ｆｅ、Ｚｎ−
Ｎｉ、Ｆｅ、Ｆｅ−Ｚｎ、Ｆｅ−Ｎｉ等の金属めっきを
施した材料や、Ｚｎ、Ｚｎ−Ｆｅ、Ｚｎ−Ｎｉ、Ｆｅ−
Ｐ等のめっき鋼板の抵抗スポット溶接に適用できる。Materials that can be welded using the electrode of the present invention include aluminum or aluminum alloys, for example, aluminum alloys such as Al--Cu type, Al--Mn type, and A type.
1-Si type, Al-Mg type, Al-Mg-Cu type, Al
-Mg-Si system, Al-Zn-Mg system, Al-Zn-M
Zn, Zn-Fe, Zn- on the surface of the above aluminum or aluminum alloy, including alloy materials such as g-Cu
Materials plated with metals such as Ni, Fe, Fe-Zn, and Fe-Ni, Zn, Zn-Fe, Zn-Ni, and Fe-
It can be applied to resistance spot welding of plated steel sheets such as P.

【００１４】尚、この抵抗スポット溶接に用いる溶接機
は、従来用いられている単相交流溶接機、単相整流溶接
機、三相低周波式溶接機、三相整流式溶接機、インバー
タ溶接機、コンデンサー式溶接機等のいずれでも良い。
又、電極形状もＲ形、ＤＲ形、ＣＦ形、ピンプル形等の
いずれでも良い。The welding machine used for the resistance spot welding is a conventionally used single-phase AC welding machine, single-phase rectification welding machine, three-phase low-frequency welding machine, three-phase rectification welding machine, and inverter welding machine. , A condenser type welding machine or the like may be used.
Further, the electrode shape may be any of R type, DR type, CF type, pimple type and the like.

【００１５】[0015]

【実施例】以下に本発明の一実施例について説明する。 実施例１ 図１は実施例１を示す模式図である。即ち、電極はＲ
形、内側電極１０，１２はΦ２．５〜５．５mm、外側電
極１１，１３はΦ１６mm、隙間１４を０．１mm、Ｒ＝８
０mmとした。被溶接材料３，４として板厚（ｔ）１mmの
Ａ５１８２Ｐ−０材を用いた。試験片の寸法は幅３０m
m、長さ２００mmとし、それを２枚重ねて用い、電極の
条件を表１のように変えて溶接した。溶接条件は次のご
とくである。 ・溶接装置 ：単相交流溶接機 ・加圧力 ：内側電極 ２７０kgf 外側電極 ３００kgf ・通電時間 ：５サイクル ・溶接電流 ：各電極での適正溶接電流値（２５０００
±１０００Ａ） ・溶接ピッチ：３０mm ・打点速度 ：１点／２秒 電極寿命の評価は、ナゲット径＝４√ｔ×９０％＝３．
６mmを確保できなくなるまでの最大溶接点数とし、途
中、電極割れ、あるいは電極溶着が発生した時は、その
時点で試験を終了した。表１に電極寿命試験結果を示
す。尚、表中の判定は、電極寿命５０００点以上を◎
印、４０００〜５０００点未満を○印、１０００〜４０
００点未満を△印、１０００点未満を×印とした。EXAMPLES An example of the present invention will be described below. Example 1 FIG. 1 is a schematic diagram showing Example 1. That is, the electrode is R
Shape, the inner electrodes 10 and 12 are Φ2.5 to 5.5 mm, the outer electrodes 11 and 13 are Φ16 mm, the gap 14 is 0.1 mm, and R = 8.
It was set to 0 mm. A5182P-0 material with a plate thickness (t) of 1 mm was used as the materials 3 and 4 to be welded. The width of the test piece is 30m
The length was set to m and the length was set to 200 mm, two of them were stacked and used, and the electrode conditions were changed as shown in Table 1 for welding. The welding conditions are as follows.・ Welding equipment: Single-phase AC welding machine ・ Pressure force: Inner electrode 270kgf Outer electrode 300kgf ・ Electrification time: 5 cycles ・ Welding current: Appropriate welding current value at each electrode (25000)
± 1000 A) ・ Welding pitch: 30 mm ・ Spotting speed: 1 point / 2 seconds The electrode life was evaluated by nugget diameter = 4√t × 90% = 3.
6 mm was set as the maximum number of welding points until it could not be secured, and when electrode cracking or electrode welding occurred on the way, the test was terminated at that point. Table 1 shows the electrode life test results. In addition, the judgment in the table indicates that the electrode life is 5000 points or more.
Mark, 4000 to less than 5000 points, ○ mark, 1000 to 40
Less than 00 points were marked with Δ, and less than 1000 points were marked with X.

【００１６】[0016]

【表１】 [Table 1]

【００１７】表１から明らかなように、本発明の電極を
使用した場合は全て５０００点以上の電極寿命を示し
た。これに対し、比較電極のNo．８は内側電極の直径が
小さいため、No．９は導電率が低く、No．１０は内、外
電極の導電率の差が小さいため、No．１１は外側電極の
融点が低いため、電極寿命は１０００点未満である。ま
た従来の電極のNo．１２〜No．１８も１０００点未満で
あった。As is clear from Table 1, when the electrode of the present invention was used, the electrode life of 5000 points or more was exhibited in all cases. On the other hand, the reference electrode No. No. 8 has a small inner electrode diameter, so No. No. 9 has a low conductivity, and No. No. 10 has a small difference in conductivity between the inner and outer electrodes. In No. 11, since the melting point of the outer electrode is low, the electrode life is less than 1000 points. In addition, the conventional electrode No. 12-No. 18 was also less than 1000 points.

【００１８】実施例２ 図２に示すように、電極はＤＲ形、内側電極１０，１２
はΦ３〜６mm、外側電極１１，１３はΦ１６mm、先端Φ
７mm、隙間１４を０．３mm、Ｒ＝４０mmＲとした。被溶
接材料として板厚（ｔ）１．２mmのＡ５０８３Ｐ−Ｏ材
の両面にＺｎ、Ｚｎ−１５％Ｆｅ、Ｚｎ−１０％Ｎｉの
めっきを２０ｇ／ｍ² 施した材料を用いた。試験片の寸
法は幅３０mm、長さ２００mmとし、それを２枚重ねて用
い、電極の条件を表２のように変えて溶接した。溶接条
件は次のごとくである。 ・溶接装置 ：単相整流溶接機 ・加圧力 ：内側電極 ３００kgf 外側電極 ３２５kgf ・通電時間 ：５サイクル ・溶接電流 ：各電極での適正溶接電流値（２５０００
±１０００Ａ） ・溶接ピッチ：３０mm ・打点速度 ：１点／２秒 電極寿命の評価は、ナゲット径＝４√ｔ×９０％＝３．
９mmを確保できなくなるまでの最大溶接点数とし、途
中、電極割れ、あるいは電極溶着が発生した時は、その
時点で試験を終了した。表２に電極寿命試験結果を示
す。尚、表中の判定は実施例１と同じである。Example 2 As shown in FIG. 2, the electrodes are DR type and the inner electrodes 10 and 12 are
Is Φ3-6mm, outer electrodes 11 and 13 are Φ16mm, tip Φ
7 mm, the gap 14 was 0.3 mm, and R = 40 mmR. As a material to be welded, a material having a plate thickness (t) of 1.2 mm, which was plated with Zn, Zn-15% Fe, and Zn-10% Ni on both sides of 20 g / m ² was used. The dimensions of the test piece were 30 mm in width and 200 mm in length. Two pieces of the test piece were used in piles, and the electrode conditions were changed as shown in Table 2 to perform welding. The welding conditions are as follows.・ Welding equipment: Single-phase rectification welding machine ・ Pressure force: Inner electrode 300kgf Outer electrode 325kgf ・ Electrification time: 5 cycles ・ Welding current: Appropriate welding current value at each electrode (25000)
± 1000 A) ・ Welding pitch: 30 mm ・ Spotting speed: 1 point / 2 seconds The electrode life was evaluated by nugget diameter = 4√t × 90% = 3.
9 mm was set as the maximum number of welding points until it could not be secured, and when electrode cracking or electrode welding occurred on the way, the test was terminated at that point. Table 2 shows the electrode life test results. The judgments in the table are the same as in Example 1.

【００１９】[0019]

【表２】 [Table 2]

【００２０】表２から明らかなように、本発明の電極を
使用した場合は、全て４０００点以上の電極寿命を示し
た。これに対し比較電極のNo．８は内側電極の直径が小
さいため、No．９は導電率が低いため、No．１０は内、
外電極の導電率の差が小さいため、No．１１は外側電極
の融点が低いため、電極寿命は１０００点未満である。
また従来の電極のNo. １２〜No．１８も１０００点未満
であった。As is apparent from Table 2, when the electrode of the present invention was used, the electrode life was 4000 points or more. On the other hand, the reference electrode No. No. 8 has a small inner electrode diameter, so No. No. 9 has a low electrical conductivity, so No. 10 is inside,
Since the difference in conductivity of the outer electrode is small, No. In No. 11, since the melting point of the outer electrode is low, the electrode life is less than 1000 points.
In addition, the conventional electrodes No. 12 to No. 18 was also less than 1000 points.

【００２１】実施例３ 図３に示すように、電極はＣＦ形、内側電極１０，１２
はΦ２．５〜５．５mm、外側電極１１，１３はΦ１６m
m、隙間１４を０．５mm、先端Φ６mmとした。被溶接材
料として板厚（ｔ）０．８mmのＺｎ、Ｚｎ−１５％Ｆ
ｅ、Ｚｎ−１０％Ｎｉのめっきを２０ｇ／ｍ² 施しため
っき鋼板を用いた。試験片の寸法は幅３０mm、長さ２０
０mmとし、それを２枚重ねて用い、電極の条件を表３の
ように変えて溶接した。溶接条件は次のごとくである。 ・溶接装置 ：インバータ溶接機 ・加圧力 ：内側電極 ２７０kgf 外側電極 ３００kgf ・通電時間 ：５サイクル ・溶接電流 ：各電極での適正溶接電流値（８０００±
１０００Ａ） ・溶接ピッチ：３０mm ・打点速度 ：１点／２秒 電極寿命の評価は、ナゲット径＝４√ｔ×９０％＝３．
２mmを確保できなくなるまでの最大溶接点数とし、途
中、電極割れ、あるいは電極溶着が発生した時は、その
時点で試験を終了した。表３に電極寿命試験結果を示
す。尚、表中の判定は実施例１と同じである。Embodiment 3 As shown in FIG. 3, the electrodes are CF type, and the inner electrodes 10 and 12 are
Is Φ2.5-5.5 mm, the outer electrodes 11, 13 are Φ16 m
m, the gap 14 was 0.5 mm, and the tip was 6 mm. Zn, Zn-15% F with a plate thickness (t) of 0.8 mm as the material to be welded
e, a plated steel sheet having Zn-10% Ni plating of 20 g / m ² was used. The width of the test piece is 30 mm and the length is 20
The thickness was set to 0 mm, two of them were stacked, and the electrode conditions were changed as shown in Table 3 and welding was performed. The welding conditions are as follows.・ Welding equipment: Inverter welding machine ・ Pressure force: Inner electrode 270kgf Outer electrode 300kgf ・ Electrification time: 5 cycles ・ Welding current: Proper welding current value at each electrode (8000 ±
1000 A) ・ Welding pitch: 30 mm ・ Spotting speed: 1 point / 2 seconds The electrode life was evaluated by nugget diameter = 4√t × 90% = 3.
The maximum number of welding points until 2 mm cannot be secured was reached, and when electrode cracking or electrode welding occurred during the test, the test was terminated at that point. Table 3 shows the electrode life test results. The judgments in the table are the same as in Example 1.

【００２２】[0022]

【表３】 [Table 3]

【００２３】表３から明らかなように、本発明の電極を
使用した場合は、全て１００００点以上の電極寿命を示
した。これに対し比較電極のNo．８は内外電極の直径が
小さいため、No．９は導電率が低いため、No．１０は内
側電極の導電率の差が小さいため、No．１１は外側電極
の融点が低いため、電極寿命は５０００点未満である。
また従来の電極のNo．１２〜No．１８も５０００点未満
であった。As is clear from Table 3, when the electrode of the present invention was used, the electrode life was 10,000 points or more. On the other hand, the reference electrode No. No. 8 has a small diameter for the inner and outer electrodes, so No. 8 No. 9 has a low electrical conductivity, so No. No. 10 has a small difference in conductivity of the inner electrode, so No. In No. 11, since the melting point of the outer electrode is low, the electrode life is less than 5000 points.
In addition, the conventional electrode No. 12-No. 18 was also less than 5000 points.

【００２４】[0024]

【発明の効果】本発明は上述の如く、アルミニウム及び
アルミニウム合金とその表面に金属めっきを施した材料
やめっき鋼板を抵抗スポット溶接する際、電極寿命を飛
躍的に向上することができる。そのため、特に自動車等
の大量生産におけるアルミ化の最大のネックになってい
た抵抗スポット溶接の改善やめっき鋼板の電極寿命改善
に大きく寄与するものである。INDUSTRIAL APPLICABILITY As described above, the present invention can remarkably improve the electrode life when resistance spot welding aluminum and aluminum alloys and materials having metal plating on the surface thereof or plated steel sheets. Therefore, it greatly contributes to the improvement of resistance spot welding and the improvement of the electrode life of the plated steel sheet, which have been the biggest bottleneck of aluminum in mass production of automobiles and the like.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の電極を用いたスポット溶接による溶接
部の断面図FIG. 1 is a sectional view of a welded portion by spot welding using the electrode of the present invention.

【図２】本発明の電極を用いたスポット溶接による溶接
部の他の例の断面図FIG. 2 is a cross-sectional view of another example of a welded portion by spot welding using the electrode of the present invention.

【図３】本発明の電極を用いたスポット溶接による溶接
部のさらに他の例の断面図FIG. 3 is a sectional view of yet another example of a welded portion by spot welding using the electrode of the present invention.

【図４】従来の電極を用いたスポット溶接による溶接開
始初期の溶接部の断面図FIG. 4 is a sectional view of a welded portion at the beginning of welding by spot welding using a conventional electrode.

【図５】従来の電極を用いたスポット溶接による電極消
耗時の溶接部の断面図FIG. 5 is a cross-sectional view of a welded portion when the electrode is consumed by spot welding using a conventional electrode.

【符号の説明】[Explanation of symbols]

１ 上電極 ２ 下電極 ３ 上側被溶接材 ４ 下側被溶接材 ５ ナゲット ６ コロナボンド域 ７ 外チリ ８ 中チリ ９ ナゲット内部の空洞 １０ 上内側電極 １１ 上外側電極 １２ 下内側電極 １３ 下外側電極 １４ 隙間 1 Upper electrode 2 Lower electrode 3 Upper welded material 4 Lower welded material 5 Nugget 6 Corona bond area 7 Outer dust 8 Middle dust 9 Cavity inside nugget 10 Upper inner electrode 11 Upper outer electrode 12 Lower inner electrode 13 Lower outer electrode 14 Gap

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 芯部の電気伝導を主目的とする内側電極
と、その周囲に加圧を主目的とする外側電極を形成し、
該内側電極として導電率が７５（ＩＡＣＳ％）以上の金
属からなり、且つ、その直径を２．５√ｔ（但しｔ＝被
溶接材料の板厚mm）とし、前記外側電極として、導電率
が内側電極よりも４０（ＩＡＣＳ％）以上低く、かつそ
の融点が被溶接材料より高い金属からなり、前記内側電
極と外側電極との間に隙間を有し、相互に可動すること
を特徴とする複動型抵抗スポット溶接用電極。1. An inner electrode whose main purpose is electric conduction of a core, and an outer electrode whose main purpose is pressurization are formed around the inner electrode.
The inner electrode is made of a metal having a conductivity of 75 (IACS%) or more, its diameter is 2.5√t (where t = the plate thickness mm of the material to be welded), and the outer electrode has a conductivity of It is composed of a metal whose melting point is 40 (IACS%) or more lower than that of the inner electrode and whose melting point is higher than that of the material to be welded, and has a gap between the inner electrode and the outer electrode, and is movable mutually. Electrode for dynamic resistance spot welding. 【請求項２】 前記内側電極の材質は、９９．９％Ｃ
ｕ、Ｃｕ−１％Ｃｒ、Ｃｕ−１％Ｃｒ−０．２％Ｚｒ、
１％アルミナ分散銅、Ｃｕ−２％Ｂｅ、９９．９％Ｔｉ
であることを特徴とする請求項１記載の複動型抵抗スポ
ット溶接用電極。2. The material of the inner electrode is 99.9% C
u, Cu-1% Cr, Cu-1% Cr-0.2% Zr,
1% alumina dispersed copper, Cu-2% Be, 99.9% Ti
The double-acting resistance spot welding electrode according to claim 1, wherein 【請求項３】 前記の外側電極の材質は、９９．９％Ｆ
ｅ、１８−８ステンレス、９９．９％Ｔｉ、９９．９％
Ｎｉ、Ｎｉ合金（アルメル）、９９．９％Ｍｏ、９９．
９％Ｗ、Ｃｕ−１０％Ｚｎであることを特徴とする請求
項１記載の複動型抵抗スポット溶接用電極。3. The material of the outer electrode is 99.9% F
e, 18-8 stainless steel, 99.9% Ti, 99.9%
Ni, Ni alloy (alumel), 99.9% Mo, 99.
The double acting resistance spot welding electrode according to claim 1, wherein the electrode is 9% W and Cu-10% Zn.