JPS60130483A - Electrode for welding - Google Patents

Abstract

PURPOSE:To provide a titled electrode which extends the life of the electrode by using an embedded metal which is hardly alloyed or melt-stuck within the specific area rate of the contact surface of the electrode for welding consisting of a copper alloy having high strength and high electrical conductivity. CONSTITUTION:About 20-70% of the area of the contact surface 1a of an electrode 1 for welding consisting of a copper alloy having high strength and high electrical conductivity is embedded with an alumina-dispersed copper alloy or a copper alloy 2 contg. tungsten, WC, etc. which is hardly alloyed or melt-stuck with the material to be welded. If the alloy is used within said area, the alloying and melt-sticking are satisfactorily prevented without deterioration in the electrical conductivity and decrease in strength and the life of the electrode 1 is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to improvements in welding electrodes used in electric resistance welding.

[Technical background of the invention and its problems]

Welding electrodes used for electric resistance welding have conventionally been generally made of chromium copper or the like. The shapes thereof vary depending on the welding specifications for the materials to be welded, such as a cap tip type, a straight tip type, a two-bent tip type, a wedge electrode type, a packer electrode type, and a seam electrode type.

However, regardless of the shape, this type of welding electrode has the following problems. That is, in recent years,
Materials to be welded that are subjected to electric resistance welding are diversified, including conventional ordinary steel sheets, zinc steel sheets, aluminum and aluminum alloys, copper and copper alloys, and the like. When such materials to be welded are subjected to electric resistance welding, it is necessary to apply a larger current to the welding electrode than when welding the ordinary steel plates. At this time, with the electrode made of chromium copper, problems such as alloying or welding of the electrode and the material to be welded due to the large current occurred.

Therefore, recently, At203
Attempts have been made to form the abutment surface from tungsten (W) when the contact surface is made of a copper alloy in which copper is dispersed, or when the material to be welded is copper or a copper alloy. However, although it is possible to improve alloy resistance and welding resistance by such measures, there is a problem in that deformation, cracking, and further deterioration are likely to occur.

This kind of problem causes deformation and roughness of the indentation on the welded material, causing problems such as impairing the aesthetic appearance and commercial value of the welded product. For this reason, it is necessary to monitor the condition of the contact surface of the electrode and perform variable polishing of the contact surface to maintain a good contact surface, which has the problem of poor welding work efficiency. .

[Purpose of the invention]

The present invention has been made in consideration of these circumstances, and its purpose is to prevent alloying and welding of materials other than ordinary steel plates even when electrical resistance welding is performed on the materials to be welded. Moreover, it is an object of the present invention to provide a welding electrode that is highly resistant to cracking.

[Summary of the invention]

The present invention provides a contact surface of an electrode body made of a high-strength, high-conductivity copper alloy such as chromium copper or chromium-zirconium copper, which comes into contact with the material to be welded and directly participates in electric resistance welding.
A metal that is difficult to alloy with or weld to the material to be welded so as to occupy an area of 20 to 70 tI6;
For example, the electrode structure has a copper alloy in which At203 is dispersed, or a copper alloy containing tungsten (W), WC, etc., embedded therein.

That is, chromium steel (Cr:0
．． 6 to 1.2) and chromium/zirconium copper (Cr:0.
3 to O, 7, Zr: 0.15 to 0.5) is used as the electrode body and alloyed to the material to be welded.

and ht203. as a metal that improves welding. W.

Copper containing 0.2 to 10 inches of WC or 0.2 to 5 inches of W
%, and is embedded in the contact surface of the electrode body so as to occupy an area of 20 to 70 inches.

Here, the ratio of the area occupied by the buried metal to the contact surface, 20 to 70%, has the following meaning. That is, when the buried area of the metal is less than 20%, alloying with the material to be welded tends to occur in areas other than the metal buried area of the contact surface of the electrode. This alloying lowers the current applied to the electrode, resulting in a decrease in welding strength, and furthermore, it becomes impossible to expect improvement in welding resistance. On the other hand, if the buried area of the metal is determined to exceed 70% of the area, the welding resistance can be greatly improved, but on the contrary, it will deteriorate more quickly.

Before welding strength decreases or welding occurs, it is necessary to polish or replace the contact surface of the electrode due to problems such as the marketability of the welded product. Therefore, no improvements can be found compared to electrodes of conventional structure.

Therefore, for these reasons, it can be said that setting the area ratio of the metal buried in the contact surface of the electrode to 20 to 70 inches plays an extremely important role.

5- [Embodiments of the Invention] Hereinafter, embodiments of the welding electrode according to the present invention will be described with reference to the drawings.

Figure 1 shows a so-called hat-shaped electrode structure, in which the contact surface 1a of the electrode body 1 with the material to be welded (not shown) is alloyed and welded with the material to be welded as described above. This figure shows a structure in which metal 2 is buried, which does not cause oxidation. Also, Fig. 2(a) (
b) shows a block-type electrode structure in which a metal 4 that does not cause alloying or welding with the material to be welded is embedded in the contact surface 3a of the electrode body 30.

Furthermore, FIGS. 3(a) and 3(b) show an electrode structure for seam welding, in which the peripheral end surface forming the abutting surface 5a of the disc-shaped electrode body 5 is alloyed with the material to be welded. This shows a structure in which metal 6 that does not cause welding is buried.

Regardless of the electrode structure (shape), or even if the electrode has a shape other than this, the contact surface of the electrode body should be covered with the material to be welded at a ratio of 20 to 70 inches in area. A welding electrode of this structure is realized by embedding a metal that does not form Alloy 6 or weld between the two.

However, now welding electrodes with the structure shown in Fig.
0.6%Cr-0.3%Zr-Cu) alloy is used as the material of the electrode body 1, and At203
The metal 2 was formed by embedding a copper alloy in which the metal 2 was dispersed.

At this time, the area occupied by the metal 2 with respect to the contact surface 1a is 10%.

We made several samples of 25%, 44chi, 69%, and 84chi. In addition, in order to confirm the effect, as a comparative example, we used general chromium copper (1-inch Cr-Cu alloy) and At
Copper alloy in which 203 is dispersed (p, t2o3: O, 7w
A welding electrode was formed using t%). However, these comparison electrodes have a structure that consists only of the electrode body 1 and does not have any other metal 2 embedded therein.

The following table shows the results using various electrodes with a thickness of 0.8 mm.
, welded a 50m wide Zn steel plate with a welding current of 12500A, 3
This shows the results of a welding test conducted under the conditions of 00 to 9 pressure and 12 Hz current flow time, and compares the number of dots until polishing becomes necessary, focusing on welding and settling. . Note that the hitting distance is 30 meters.

9- [Effects of the Invention] As evidenced by the experimental results shown in this table, the welding electrode having the structure according to the present invention has a higher welding point before polishing is required compared to the electrode having the conventional structure. The number of times can be increased sufficiently.

This means that the life of the electrode has been extended,
It is possible to reduce the number of times polishing is required. Therefore, there are great practical effects, such as reducing the number of times the welding line is stopped and polishing the electrodes, and improving the operating efficiency of the production line.

[Brief explanation of drawings]

FIGS. 1 to 3 are diagrams each showing the structure of a welding electrode according to an embodiment of the present invention. 1, 3, 5--electrode body, 1a, 3a
, 5 a - Contact surface, 2, 4.6... Metal that is alloyed with the material to be welded and difficult to weld (buried metal). Applicant's agent Patent attorney Takehiko Suzue 10- Figure 1 Figure 3 (a) Figure 2 (b)

Claims (2)

[Claims] (1) In a welding electrode used for electric resistance welding,
A metal that is difficult to alloy with or weld to the material to be welded is placed on the contact surface of the electrode body made of a high-strength, highly conductive copper alloy that comes into contact with the material to be welded so as to occupy an area of 20 to 70 inches. A welding electrode characterized by having embedded therein. (2) The metal buried in the contact surface of the electrode body is At20
2. The welding electrode according to claim 1, which is made of a copper alloy or the like in which C. 3 or the like is dispersed.