JPS59179286A - Tungsten electrode - Google Patents

Abstract

PURPOSE:To provide a titled electrode which decreases consumption of a non- consumable tungsten electrode in arc welding using said electrode by conducting inert gas to the central part of the electrode thereby preventing the magnetic blow of an arc and improving arc start. CONSTITUTION:A tungsten electrode is formed into a hollow pipe shape. The electrode is mounted in a holder and inert gas is blown to the tip thereof along the central hole part and the outside circumference of the electrode. The deviation of an arc is thus prevented, the arc is stabilized and the consumption of the electrode is considerably decreased. Arc start is improved by the formation of a sharp edge to improve operability and the welding defect owing to air inclusion is prevented.

Description

[Detailed description of the invention] This invention relates to tungsten electrodes.

Inert gas arc welding is an arc welding process performed in an atmosphere containing a small amount of active gas such as argon or helium, and as shown in FIG. Welding is performed by replacing the atmosphere 5 on the surface of the contact metal 40 with this inert scum 1.

In this bath welding method, when the f6 welding material is a thin plate with a thickness between 0.6 Vrm and 3 Vrm, a tungsten inert gas (TI) using a non-consumable tungsten electrode is used.
G) Arc welding method is applied.

In this TTG welding, a DC current modulated with a high frequency current is used to stabilize the arc and to ignite the weld without bringing the electrode into contact with the weld metal.

In welding in which such a -flow 6 is applied between the electrode 2 and the welding area 4 as shown in Fig. 3, the arc 7 is not formed at the shortest distance between the electrode 2 and the weld metal 4, but rather It is formed by This is due to the phenomenon of being blown by the magnetic field created by the energizing path (magnetic blowing), which causes the arc to become less concentrated, and the arc to stop flowing at the desired location B.

When this welding method is used for bath welding the metal plates 8 and 9 shown in FIG. 4, various problems arise. That is, the other metal plate 9 having a slint t'la is fitted to the slint 8a formed on one of the two thin metal plates 8.9 in an alternating pressure manner, and these metal plates are Ti the difference part 10 of plates 8 and 9.
G welding causes the following problems.

(1) In the case of @flow pressure polarity, the flow of the arc 7 deviates from directly downward and shifts to one side.

(2) The flow of the arc to the slit 8a becomes poor.

(3) Since the metal plates 8 and 9 are thin, if the welding time becomes long, these plates will become sluggish and the product quality will be lost.

By the way, in order to stably generate an arc, it is generally done to polish the tip of the electrode 2, which is the arc generating end, into a conical shape to form a conical surface 2&. ing.

However, in conventional inert gas arc welding using such a rounded pole, the tip of the electrode 20, which has been polished into a conical shape, becomes rounded as the number of welding increases, and the apex angle set at the beginning is lost. become unable to maintain it. For this reason, (1) bead suke and yuka complication become unstable.

(2) Since the gigang between the weld metal and the tungsten electrode becomes larger than at the time of setting, the arc start becomes unstable.

(3) In order to maintain stable overlapping, the tip of the tungsten electrode is frequently modified, and in order to maintain a constant gap between the weld metal plate and the tungsten electrode, the tungsten electrode is placed on the welding metal side. The tungsten electrode must be replaced or the tungsten electrode must be replaced.

(4) On the surface of the remaining end of the bath welding, the inert gas causes convection and air is drawn in, resulting in defects in welding.

This invention was made in view of the above-mentioned circumstances, and by forming a true through hole in the center of the electrode to allow inert gas to flow through, the arc is stabilized by eliminating unevenness of the arc. This greatly reduces the amount of wear and tear caused by arc starts, greatly reduces the number of times of polishing for polarization, improves work efficiency, and prevents air entrainment. The purpose of the present invention is to provide a tungsten electrode that can prevent welding defects.

An embodiment of the present invention will be described below with reference to FIGS. 5 and 6. Reference numeral 11 shown in FIG. 5 is a tungsten electrode (tubular), and a through hole 12 is formed in the center of the electrode to allow inert gas to flow therethrough. Tungsten
A sharp edge 13 is formed along the circumference at the tip of the tip.

When this tungsten electrode 11 is attached to the bath welding torch 14 and inert gas arc 1l15 contact is performed, the outside of the tungsten electrode 11 and the through hole 12 are
An inert gas 15 flows through each.

As a result, the eccentricity of the arc is eliminated, the arc becomes stable, the wear of the tungsten electrode 11 is reduced to just 1, and the tip of the tungsten electrode 11 always has a sharp edge 13.
is formed, the arc start is very good, the number of times the tungsten electrode 11 is sharpened can be significantly reduced, workability is improved, and air entrainment due to inert gas 150 convection is significantly reduced, preventing welding defects. can be prevented.

In addition, in the above embodiment, the tip end surface and the outer peripheral surface of the tungsten electrode 11 are offset at an angle, but the present invention is not limited to this. For example, as shown in FIG. A Taber curve 22 may be formed on the surface.

Next, an experiment in which inert gas arc welding was performed using this tungsten electrode 21 will be described.

Experiment 1. A conventional tungsten electrode 2 (diameter 1.6 mm, length 50-60 mm) shown in FIG.
An inert gas arc welding ratio soft experiment was carried out under the conditions shown in Table 1 using a hole diameter of 0.8 mm.

As shown in the same table, this result shows that with the conventional tungsten electrode 2, the arc became unstable after only 30 tests, and it became impossible to continue the subsequent tests after 100 tests. On the other hand, in the tungsten pole 21 of the present invention, the arc remained stable even after 500 tests.

Table 1 Experiment 2. II. For the welding torch 14, we used the conventional tungsten pole 2 used in Experiment 1 and the uninvented tungsten pole 21, and welded the welding torch 14 at the intersection 10 of the metal plates 8 and 9 shown in FIG. Inert gas arc welding ratio yield experiments were conducted.

The metal plates 8 and 9 used are Zircaloy plates with a plate thickness of 0.3 ynttt, and the groove width of the slit 8a is 0.5711K.
The gap 23 shown in FIG.

The arc generation situation in this experiment is as shown in Fig. i8 (aJ) and Fig. 9 (a). In the case of the conventional electrode 2, (1) the above-mentioned magnetic blowing phenomenon occurs depending on the size of the gap 230. As a result, the arc 7 is shifted to one side, and there are places where welding cannot be performed. (2) The arc start gradually deteriorates, and there are places where bath contact cannot be made. (3) The number of welding cycles is limited to a few tens of times. It was done.

On the other hand, when the tungsten electrode 21 of the present invention is used, (1) the arc 24 is
The arc 240 flows evenly to the 0 welding locations, and no deviation of the arc 240 occurs. (2) Even if the gaps 23 on both sides of the metal plating plate 9 at the intersection 10 are slightly different, the arc 24 is uniformly generated. (3) There is almost no wear on the tungsten electrode 210, and the sharp edge remains formed at the tip of the tungsten electrode 21, so the arc start hardly decreases even during the 500th welding. (
4) Good results were obtained, such as a reduction in air entrainment due to shielding gas convection and an improvement in welding performance.

As explained above, according to the present invention, inert gas is passed through the center of the electrode. Since the through-hole is formed to prevent the arc from shifting, the arc is stabilized and the wear of the electrode is greatly reduced. Increase the number of polishing times to 1
The thickness can be reduced to 1μ, improving workability, preventing air from being entrained, and preventing welding defects.

[Brief explanation of the drawing]

Figure 1 is a partially omitted cross-sectional view of an inert gas arc 6-contact torch equipped with a conventional tungsten electrode, Figure 2 is a partial front view of a conventional tungsten electrode, and Figure 3 is an illustration of the magnetic blowing phenomenon. Figure 4 is a perspective view showing the welding state at the intersection of two metal plates, the fifth factor is a partially cutaway sectional view showing an embodiment of the present invention, and Figure 6 is a diagram showing the tungsten electrode. FIG. 7 is a partially omitted cross-sectional view of an attached inert gas arc welding torch, and FIG. 7 is a partially omitted cross-sectional view of a tungsten electrode showing another example of this inert gas arc welding torch. FIG. 8(a)
is a diagram showing the welding state of direct metal plates using the tungsten electrode, FIG. 8(b) is a cross-sectional view of FIG. 8(a),
Figure 9(a) is a diagram showing the state of welding a metal plate directly using a conventional tungsten electrode;
). 11.21...Tungsten electrode (tubular tube), 12.
...Through hole. Figure 7 Figure 6 (0) X/N ↓ Figure 8 (b) Figure (bl

Claims (1)

[Claims] A special tungsten electrode with a true through hole formed in the center of the '8L& to allow inert gas to flow through it.