JPS61209774A - Tig welding method - Google Patents

Abstract

PURPOSE:To obtain the molten metal having the chemical component of the intermedium of a using filler material by melting two pieces of the filler materials having different chemical compositions in a one molten pool simultaneously. CONSTITUTION:Two pieces of filler materials are melted by arc 3 to form a molten pool 4 but the molten pool 4 is stirred up by the convection current caused by the arc force and heat of the arc 3 and becomes that which mixes the components of the two filler materials. And the component of this mixed molten metal can be adjusted if necessary. Namely the composition of the molten pool 4 can be changed by the adjustment in the feeding speed of the filler material because of the molten quantity being adjustable by changing the respective chemical component of the filler material and the feeding speed. Even in case of using more than three pieces of the filler materials, it is better to arrange so as to feed to the molten pool 4 from the front part and rear part of a tungsten electrode 6 or both sides of the front part and rear part. Therefore several kinds of molten metals 12 having the intermediate chemical component of the using filler material are obtainable.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a TIG welding method that can easily obtain weld metals with a wide range of compositions. A piece of filler material is fed from the K111 side of the arc emitted from the tungsten electrode, and is melted by the arc heat to form a weld bead. In this case, a neutral inert gas that does not decompose even at high temperatures, such as rounding, aluminum, helium, etc., is used as the shielding gas to prevent oxidation of the tungsten electrode and the molten pool. The chemical composition of this rounded filler metal itself and the chemical composition of the weld metal melted and formed by the arc of the tungsten electrode are almost identical, unless dilution of the base metal is taken into account. Therefore, in the TIG welding method, the chemical composition of the weld metal can generally be considered to be the chemical composition of the filler metal. Therefore, in order to obtain a weld metal with a predetermined chemical composition, it was necessary to procure a filler metal with approximately the same composition.

However, it is difficult and economically burdensome to procure filler metal according to the chemical composition of a given weld metal, and despite this, there has been no significant improvement in filler metal. The current situation is that this is not the case.

On the other hand, in the MIG welding method, a mixture of argon and oxygen or carbon dioxide is used as the shielding gas, and by changing the amount of oxygen or carbon dioxide mixed, the oxygen potential of the entire shielding gas can be adjusted. , Tl on the wire.

ZrJi＊N! When the weld metal contains an oxidizing element such as n, it is possible to control the amount of the oxidizing element in the weld metal by adjusting the oxygen potential of the shielding gas.

In the TIG welding method, if such a shielding gas is used, the amount of oxidizing elements in the weld metal can be controlled in the same manner as in the MIG welding method, but in TIG welding, the tungsten electrode becomes oxidized and consumed, making it unusable.

The oxidized and consumed tungsten of the electrode transfers to the weld metal,
The chemical components of the weld metal may be unintentional, and the electrodes may become worn out, making it impossible to maintain a constant arc and making welding impossible.

No. 1 Problems to be Solved by the Invention The present invention uses at least two types of filler metals with different chemical compositions, and changes the melting amount of the two types of filler metals to achieve a chemical intermediate between the filler metals used. The aim is to obtain various types of weld metals with different compositions.

Means for Solving the Problems The gist of the present invention resides in a TIG welding method characterized in that two filler metals having different chemical compositions are simultaneously melted in one molten pool.

The present invention will be explained in detail below. 1 and 2 are perspective views showing one embodiment of the method according to the invention. In Fig. 1, an arc 3 is generated between a tungsten electrode 6 connected to a power supply IK and a base metal 2, and a molten pool 4 is surrounded by a gas 5 to form a molten pool 4 isolated from the atmosphere. Set in the same way. Then, two filler metals 7 and 8 having different chemical compositions are placed in front of the tungsten electrode traveling direction 9, and the filler metals 7 and 8 are simultaneously fed in the directions 10 and 11 toward the arc 3 and the molten pool 4. The filler metal 7.8 is simultaneously melted by the heat of the arc 3 to form a molten pool 4, which becomes a weld metal 12 when solidified.

Figure 2 shows a situation in which filler metal 7.8 is fed from both sides of the tungsten electrode in the same manner as in Figure 1 to form weld metal 12, and the other configuration is the same as in Figure 1. It is.

These two filler metals are melted by the arc 3 and form a molten pool 4, but the molten pool 4 is sufficiently stirred by convection caused by the arc force and heat of the arc 3, so the molten pool 4 is formed by the two molten metals. It is a mixture of filler ingredients. The components of this mixed weld metal can be adjusted as necessary. By changing the chemical composition and feeding speed of each of the filler metals 7 and 8, the amount of melt can be adjusted depending on the temperature, so the composition of the molten pool can be made more efficient by adjusting the feeding speed of the filler metals 7 and 8. can be changed to

Since the present invention is constructed as described above, by procuring two types of filler metals with different chemical compositions, several types of weld metals having chemical compositions intermediate to the filler metals of 281[class] can be procured. You can also get it.

In addition, in Figures 1 and 2, the number of filler metals is 2, respectively.
Although the case where this is used is shown, even when three or more electrodes are used, they may be arranged so that they are fed to the molten pool 4 from the front, the rear, or both the front and rear sides of the tungsten electrode.

Example The present invention will be explained in more detail below using Examples.

A test plate made of 3.5% Ni steel with the specifications shown in Table 1 was prepared with a groove with θ = 45°, t = 12.7 mm, and G = 6.4 dew in Figure 3. TIG welding was performed under the welding conditions shown in Table 3 using two filler metals A and B, each having a diameter of 1.2 m and having a different composition of C content shown in Table 2 and 81 content.

Welding condition test JllL1 was tested using only A filler metal with a low C content and 81 content, with a filler metal melt amount of 111 min/! E2 feeds filler metal 8.25 #r/win e filler B at 2.75 JFr/m1n so that the ratio of filler metal A to filler B is 3:1, and The total melting amount of the filler material was 11 gr/m1n. Test A3 is 5 each so that the ratio is 1:10.
．． 5g1n was fed, and test A4 was A4 so that the ratio was 1:3.
2.75 filler metal,! Fr/min * B filler metal is fed at 8.25 #r/nin, and the amount of melted filler metal is 11 g.
r/min.

Tester 5 performed TIG welding using only B filler metal with high C and Si contents.

After welding was completed, analysis samples were prepared from the weld metal at the center of the groove of the test material, JIS, A2 round bar tensile test piece, and JIB.

A No. 4 Charpy impact test piece was taken and subjected to an analytical test, a tensile test, and a Charpy impact test.

Table 4 K shows the analytical test results of these weld metals.

The tensile test results and impact test results are shown in Table 5.

In this example, filler metals with different amounts of C, St, F) Mn, and Ni were combined and welded in almost the same amount, so the chemical composition of the weld metal was as clear from Table 4, as shown in Table 4. The value depends on the amount of melting. In other words, if Mn and Nl are almost the same for the two filler metals, the chemical composition of the weld metal will be almost the same as the original filler metal even if the melting amount of the two filler metals is changed. Equal and unchanged.

On the other hand, if the C and St amounts of the two filler metals are different, the chemical composition of the weld metal will be a value that is approximately divided into the ratio of the melting amounts of the two filler metals. This example shows the case where three types of weld metal components are systematically obtained using two types of filler metals, but it can be increased or decreased as necessary, and it is possible to know the mechanical properties of weld metal depending on the chemical composition. can. By following this process in reverse, it is possible to find the chemical composition of the weld metal that has the required mechanical properties, and from this chemical composition it is also possible to determine the filler metal and its melting amount.

26 Effects of the Invention As described above, in the conventional TIG welding method, the chemical composition of the weld metal is the same as the chemical composition of the filler metal. However, by procuring two types of filler metals using the method of the present invention, the feeding speed of each filler metal is adjusted and melted at the same time. It has become possible to efficiently obtain weld metal with an intermediate chemical composition.

[Brief explanation of drawings]

1 and 2 are perspective views showing embodiments of the present invention,
FIG. 3 is a diagram showing the shape of the test plate. 1... Power supply, 2... Base material, 3... Arc, 4...
- Molten pool, 5... Shielding gas, 6... Tungsten electrode, 7... Filler metal, 8... Filler metal, 9... Welding direction, 1o... Filler material feeding feeding direction, 11... filler metal feeding direction, 12... weld metal, 13... test plate, 14... true metal.

Claims (1)

[Claims] A TIG welding method characterized by simultaneously melting two filler metals with different chemical compositions in one molten pool.