JPS63993A - Manufacture of arc melting electrode - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing an electrode for arc melting by arc welding sponge titanium molded bodies together.
Specifically, the present invention relates to a method for manufacturing an arc melting electrode that successfully produces a high quality arc melting electrode efficiently by using a titanium consumable electrode as an electrode for arc welding.

[Prior Art] In manufacturing an electrode for arc melting by arc welding a sponge titanium molded body, a method using a non-consumable electrode such as TIG welding or plasma welding is generally adopted. .

By the way, impurities such as chlorine and low boiling point metals (Na, Mg, etc.) are mixed into the titanium sponge molded body due to raw material conditions, and furthermore, the titanium sponge molded body itself is porous and contains air bubbles. Therefore, it has been confirmed that spatter is likely to occur during welding. Furthermore, it has been experienced that the generation of spatter is particularly troublesome in TIG welding, plasma welding, etc. that use non-consumable electrodes. One of the reasons for this is thought to be that these welds are performed under relatively low current conditions and the molten pool is small, resulting in a rigid arc being formed directly on the base metal surface, and also because the rigid arc is formed directly on the base metal surface. Low boiling point metals (Na and M
This is thought to be due to the fact that the molten metal (g, etc.) is rapidly heated by the arc and undergoes explosive expansion, which causes the molten metal to be blown away.

When such a large amount of spatter is generated when performing TIG welding, the spatter adheres to the tungsten electrode, which accelerates wear and tear of the electrode. In extreme cases, the tungsten electrode may melt, causing molten tungsten to flow into the molten pool. There was even a risk that the titanium ingot would fall and deteriorate the quality of the titanium ingot.

In any case, when the wear and tear of the tungsten electrode becomes severe, it becomes necessary to replace the electrode frequently, and welding work has to be interrupted repeatedly.
The disadvantages of G welding, such as low welding current (200 to 300 A) and low welding speed (15 to 20 cm/min), resulting in low welding efficiency, become even more noticeable. In the plasma welding method, spatter adheres to the tip of the orifice body, causing clogging of the tip, making it difficult to remove the adhering spatter. In the unfortunate event that the tip becomes clogged, it will be necessary to replace the four tip parts, resulting in interruption of welding work and
They have no choice but to accept the inconvenience of reduced efficiency and increased costs for replacement parts.

Furthermore, when a large amount of spatter occurs as mentioned above, the shielding effect of the inert gas (Ar gas, etc.) is impaired, and as a result, a large amount of impurities such as oxygen and nitrogen are mixed into the weld metal, impairing the quality of the electrode for arc melting. It also causes the negative effect of lowering the amount.

[Problems to be Solved by the Invention] The present invention has been developed in consideration of these circumstances, and allows high-speed welding to be performed without interrupting the welding operation, while reducing the amount of impurities in the welded part. It is an object of the present invention to provide a method of manufacturing an electrode for arc melting that can reduce the number of electrodes as much as possible.

[Means for Solving the Problems] The gist of the method for manufacturing an electrode for arc melting according to the present invention is that the electrode for arc melting is manufactured by welding sponge titanium molded bodies together using a titanium consumable electrode. exists.

[Function] The present invention is constructed as described above, but the point is that when producing an electrode for arc melting by welding sponge titanium molded bodies together, welding is performed using a titanium consumable electrode. An essential characteristic exists at a point.

The reason why spatter is suppressed when arc welding is performed using a titanium consumable electrode can be considered as follows.

In other words, in the case of titanium consumable electrodes, the base metal is heated via a molten pool rather than directly heated as in TIG welding and plasma welding, so Na
This is thought to be because the vaporization of low-boiling metals such as Mg and Mg progresses relatively slowly.

As described above, by adopting the configuration of the present invention, it is possible to reduce the occurrence of spatter, thereby ensuring a shielding effect during welding, and therefore preventing oxygen and nitrogen from entering the welding area, and arc melting. It is possible to improve the quality of the electrode for use. Furthermore, in the present invention, high current welding can be performed without the problem of quality deterioration of the titanium ingot due to melting and falling of the tungsten electrode, which is the case when consumable electrodes are used, and therefore the welding speed can be reduced. It can be done satisfactorily.

The present invention is constructed as described above, and does not specify the welding conditions or the shape of the titanium consumable electrode, but in order to further improve welding workability, it is necessary to It is recommended to use a strip.

When the strip-shaped titanium consumable electrode is fed so that its width direction is perpendicular to the welding line and welding is carried out, the arc becomes strip-shaped! Since the bead is generated along the poles, a wide bead can be obtained without performing a weaving operation. Therefore, the groove may be wide, and the allowable range of welding conditions becomes wider. Therefore, the tolerance of the groove gap and groove target position increases. This is particularly effective when connecting a plurality of compression molded bodies by welding. Further, there is no need for a high-grade groove tracing device or the like.

The above-mentioned strip-shaped electrode can be easily obtained by cutting a wide titanium coil or the like, and is more efficient than processing titanium, which has poor formability, into a round wire. In other words, the welding wire (round wire) is
- Generally, it is manufactured by plastic working (for example, about 1.8 mmφ) a titanium rod (for example, 6 to 9 mmφ). However, titanium is a metal with poor formability in cold conditions.
Moreover, vacuum annealing is required because it is oxidized even at a temperature of about 400° C. at most. Therefore, when obtaining a welding rod by plastic working a titanium rod, it cannot be carried out in a continuous process, and it is necessary to go through an extremely large number of independent processes, which increases costs. .

However, in the case of a band-shaped electrode (not a rod-shaped electrode), it can be manufactured by simply cutting a wide titanium coil into strips, so the problems like the above-mentioned rod-shaped electrode do not occur. Furthermore, it is extremely economical because leftover materials and scraps can also be used.

[Example] Example 1 Fig. 1 is an explanatory diagram showing an apparatus used in the method of the present invention, in which 1 is a sponge titanium molded material that is a material to be welded, 2 is a titanium consumable electrode, 3 is a current-carrying tip, 4 is a gas shield nozzle, 5 is a shield gas supply port, and 6 is an electrode feeding roller.

The titanium consumable electrode 2 is fed by the electrode feeding roller 6, and shielding gas (Ar gas) is supplied from the shielding gas supply port 5.
is introduced into the titanium consumable electrode 2 through the current-carrying tip 3.
An arc current is applied to the titanium sponge molded body 1 to generate an arc between the titanium sponge molded body 1 and welding is performed.

An example of the results of welding in this manner is shown in Table 1 together with the welding conditions.

Note that Table 2 shows comparative examples.

It can be seen that when the method of the present invention is used, the welding speed is higher and the number of welding interruptions is smaller than in the comparative example. Therefore, the total welding time is short and welding efficiency is excellent.

Furthermore, the amount of oxygen and nitrogen in the weld metal was also reduced, making it possible to reduce the amount of impurities.

Example 2 As a titanium consumable electrode, band-shaped electrodes with various thicknesses and widths were used, and welding was carried out under the following conditions using the same equipment as in Fig. 1, and the results are summarized as shown in Table 3. Ta.

Material to be welded Sponge titanium Bevel shape 30'V, depth 10mm Shielding gas Ar 100J2/min Welding machine DC constant voltage power supply polarity Wire (+) Welding current 400-100OA An arc cannot be obtained. If it exceeds 1000 A, there will be a lot of spatter.) Arc voltage 25 to 40 V (If it is less than 25 A, a short circuit will occur. If it exceeds 40 V, the arc will become unstable.) Welding speed 40 cm/min ￥ Table S3 ◎: f! Very good O: Good △: Possible, that is, when the electrode thickness was 0.4 mm or less, buckling of the electrode easily occurred and the arc was unstable. - When the thickness was 1.3 mm or more So,
Even when the current density was reduced and a large current of 100 OA was passed, a stable spray-like arc could not be obtained. Further, it is difficult to wind it into a coil shape, which is not practical.

However, if the width of the electrode is 4 mm or less, the spread in the width direction is small and a wide bead cannot be obtained. - Width is 25mm
When the value exceeded 100%, the arc spread too much and the bead shape was slightly poor.

From the above results, it is found that the strip electrode has a thickness of 0.5 to 1.
It is recommended to use one with a diameter of 2 mm and a width of 5 to 25 mm.

[Effects of the Invention] Since the present invention is configured as described above, high-speed welding can be performed without interrupting the welding operation when manufacturing an electrode for arc welding by arc welding a titanium sponge molded body. Furthermore, it has become possible to reduce the amount of impurities in the welded area as much as possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing an example of an apparatus in which the method of the present invention is implemented. 1... Sponge titanium molded body 2... Titanium consumable electrode

Claims (1)

[Claims] A method for manufacturing an electrode for arc melting, characterized in that the electrode for arc melting is manufactured by welding sponge titanium molded bodies together using a titanium consumable electrode.