JPS60206580A - Method for shielding inside welding surface - Google Patents

Abstract

PURPOSE:To release a shielding gas from a shielding gas generating source adsorbed with the shielding gas by weld heat and to shield easily an inside welding surface by disposing said generating source right under the butt parts to be welded and welding said parts. CONSTITUTION:Bodies 10a, b to be welded which are two pipe bodies are butted to each other and a shielding gas generating source 11 formed by adsorbing a non-oxidative shielding gas such as Ar into molecular sieves loaded with a chemical such as zeolite is disposed into the pipe right under the parts to be welded consisting of a groove. A welding torch 12 and a filler rod 13 are made to approach to the parts to be welded from above in this state and an arc is formed between the electrode of the torch 12 and the bodies 10a, b by which the base of the welding groove and the rod 13 are melted and mixed and a weld bead 14 is formed. The non-oxidative gas adsorbed to the source 11 is released from said source by the weld heat thereof to shield the rear of the bead 14, by which the defectless weld zone is obtd.

Description

[Detailed description of the invention] This chapter relates to a welding inner surface shielding method.

Conventionally, the inner surface shielding method for butt welding of pipes in TIG welding is carried out as shown in Figure 1.1 in Figure 0 shows the grooves of the pipes 3a and 3b to be welded which are butt welded. This is a TIG welding method in which TIG welding is performed using a welding rod 2 on the part. 4 is a weld bead that is overlaid on the groove. T.I.
The G torch 1 is connected to a welding power source that does not appear in the figure.

A shielding jig 5 is inserted into the tubes 3a and 3b, and a shielding gas 6t such as Ar is supplied from a supply source through channels 7a...7d that branch toward the grooves. It looks like this.

That is, a welding arc is generated between the electrode, which is a part of the TIG)-chi 1, and the pipes to be welded 3b, 3b. The welding arc melts the bottoms of the welding grooves of the welded tubes 3a and 3b, but the melted welded tubes 3a and 3b are mixed with the melted molten rod 2.

It solidifies to form a weld bead 4. in this case.

The back surface of the welding bead 4 is covered with shielding gases 7a, 7b, 7c discharged from the inner surface shielding jig 5 inserted and fixed from the ends of the pipes 3a, 3b to be welded.

Since it is shielded by 7 drc, you can get 11 ura wave speed.

However, in this method, it is necessary to insert the inner shield jig 5 into the pipes to be welded 3a, 3b, and therefore a vcb opening is required. For this reason.

It has the disadvantage that it cannot be applied when there is no opening, or even if there is an opening, it is far away from the welding area.

Moreover, FIG. 2 shows a conventional internal shielding method using a thin tube. In Figure 2, 1 is KTIG (same as the fan)-
H, 2 is filler rod % 3a.

3b is a temporarily welded pipe, and 4 is a weld bead. 5a is a thin tube inserted into the root gap (doors 1 to 3) opened in the groove. The thin tube 5avc is filled with shielding gas 6 such as Ar.
is supplied and branched into channels 7e and 7f to prevent oxidation of the back surface of weld bead 4.

However, since this method utilizes the root gap to insert the thin tube 5at-, it cannot be applied when the grooves are in close contact, and even when there is a root gap,
As welding progresses, the root gap is successively filled by weld beads 4. Therefore, immediately after the first layer welding
However, since the thin tube 5at has to be pulled out, the inner shield becomes incomplete and welding defects often occur.

The present invention has been devised in view of these points, and provides a method for shielding the inner surface of welding, which is independent of the shape and dimensions of the object to be welded, and which can easily obtain a healthy welded part. be.

That is, in the present invention, all the shielding gas generation sources adsorbing non-oxidizing shielding gas r are installed directly below the welded part where the welded objects are brought together, and the welding is carried out on the welded part. This is a customer-friendly internal shielding method that dissipates the shielding gas from the source of the shielding gas using the heat generated during the process.

Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in FIG. 3, the object to be welded 10a.

10 a Butt the two tubes together Next, place the shield gas generation source 11 that adsorbs the shield gas inside the tube corresponding to the part to be welded, which is the groove formed in the butt part. Install.

Here, the shielding gas is a non-acidic gas such as IrO. In addition, the raw saliva 11 that generates shielding gas adsorbs and captures the shielding gas at room temperature, but when heat during welding is applied, the adsorption action is released and the shielding gas is released. For example, it is composed of solidified chemical ropes and molecular sieves.

The chemical rope molecular sieve will be explained below.

nt - the valence of the supported metal Me (e.g. Na).

``O* / S 102 =: If rn, then there is a group of aminosilicate compounds collectively called zeolites, represented by the chemical formula Me(-)-(1(h)m''8fox).These compounds are Because it has a three-dimensional network structure, INa has a sandwiching surface area of several hundred m2 and exhibits extremely good adsorption ability.Furthermore, the pores through which the adsorbed gas enters are called windows. Its diameter varies depending on the type of metal supported.-For example, the industrially frequently used n1bh type zeola
) n is different from 5A.

For this reason, molecules smaller than the window diameter are adsorbed, but larger molecules are not adsorbed, so it acts just like a sieve, and zeolite is called molecular vP (Mole).
It is sometimes called curar 5ieve). Kumi's loaded molecular sieves are an application of this property.

In other words, if a gas whose molecules are slightly larger than the window diameter is adsorbed at high temperature and pressure, it will not be confined in the adsorbent at high density and will remain as it is even if the temperature is returned to normal temperature and atmospheric pressure. Zeolites with such functions are called chemical rope molecular sieves.

The chestnut is shown below.

Ar is a type of rare gas and has an atomic diameter of about 3°4A. On the other hand, K-A biolite has a diameter of 3A as mentioned above, so it usually does not adsorb Ar, but at a temperature of 350°C.
, when contacted with 1'-r'<K-A zeolite at a pressure of 2.600 ata, 10ocI per gram under standard conditions! L
Ar about 8? ! ``Adsorb.

Even if the device is used at different temperatures, the spontaneous release remains at around 20%. When heated to fL+a-250℃, most of the Ar
Release 1d.

Thus, a welding torch 12 and a filler rod 13 are placed above the multiple joints.
1, a part of the welding torch 12 is brought close to the welding power source (not shown), and a welding arc is generated between the electrode and the objects to be welded 10a and 10b.

The welding arc melts the bottom of the welding groove of the objects to be welded 10a, 10b, but the melted objects to be welded 10a,
Similarly to 10b, the melted filler rod 13 is mixed and solidified to form a weld bead 14.

By this welding, the Elishield gas generation source 11 is heated by the arc penetrating the root gap and keyhole of the groove, or by the radiant heat of the weld bead, and non-oxidizing gases such as fL, pLr, etc. are generated. Therefore, the back surface of the weld bead 14 is shielded from air, making it impossible to obtain a sound weld.
Ru.゛Again. After welding, the shielding gas source 1) is
Air and water 1 from the ends of the objects to be welded 10 a and 10 b
etc., it can be easily ejected.

Note that the method of the present invention is applicable to TIG welding, MIG welding with 1M
It can be applied to inner shields for welding, plasma welding, slight arc welding, and Uranami welding.

Moreover, FIG. 4 shows another example of the method of the present invention. In this example, a chemical port is used as the shielding gas generation source 15.
One container is used in which a dated molecular knob is housed in a porous container 15a made of glass wool, plastic, water paper, or the like. The other points are the same as those of the embodiment, so the explanation will be omitted.

Even in such other embodiments, shielding gas (for example, 14Ar) is released from the porous container 15a due to arc heat or radiant heat from the weld bead 14. released A
H/(shielding gas is welded object 10a, 1θb
Since it remains in the space formed by the inner surface of the porous container 15a and the porous container 15a, the back surface of the weld bead 14 can be efficiently shielded.

As explained above, according to the weld inner surface sifting method according to the present invention, it is possible to easily obtain a sound welded portion regardless of the shape and dimensions of the object to be welded.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing the state in which pipes are butt welded using the conventional inner shielding method, FIG. 3 is an explanatory diagram showing the method of the present invention, and FIG. 4 is an explanatory diagram showing the method of the present invention. Other examples? FIG. IQ a e 10 b... object to be welded, 11... shield gas generation source, 12... welding torch, 13...
Adder rod. 14... Welding bead, 15... Shield gas generation source, J5a... Porous container. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2 Box 6 Figure 3 1 Figure 4

Claims (1)

[Claims] A shielding gas generation source adsorbing non-oxidizing shielding gas is installed directly under the welded part where the welded objects are brought together, and the welding is performed on the welded part, and the shielding gas is generated by the heat during welding. A welding inner shielding method characterized by releasing the shielding gas from the source.