JPH10225771A - Shield structure of welding torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the density of input heat against a welding objective member, to improve the exactness of arc and to highly speedily execute arc welding by providing a gas introducing means to respectively guide a 1st gas and a 2nd gas nearby the top end of an electrode, supplying both side gases in an arbitrary ratio, and composing to use them for welding. SOLUTION: A 1st gas G1 (Ar gas) with a 1st gas introducing means 4a, a 2nd gas G2 (He gas) with a 2nd gas introducing means 4b, these are guided respectively at the same time nearby the top end 20 of an electrode 2. Then, both side gases are made in a mixture gas and it shields the circumference of an arc (a). In this time, because an Ar is made rich in an upper generating range a10 and the current density is made large, so the pressure of the arc a is made high and the exactness of the arc a can be kept. In the lower generating range all, the He is rich, a fan like spreading of the arc a can be restricted a few in a proper degree, the shape of the arc a is made like a hanging bell, and the input heat density can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield structure of a welding torch used for electrode type arc welding.

[0002]

2. Description of the Related Art Conventionally, a welding torch used for electrode-type arc welding has two positive and negative electrodes for generating an arc, which are formed by a workpiece (member to be welded) as a base material and an electrode. Has the function of fusing with the high heat of the arc and fusing and welding. Here, when the conventional welding torch 1D shown in FIG. 8 is used to horizontally butt-weld workpieces 60d, 60d using two metal plates as members to be welded, the workpieces are supplied from a gas supply source (not shown). The gas G is supplied to the supply cylinder 40d.

[0003] The gas G supplied to the supply cylinder 40d is ejected from an ejection hole 45d, and a high-impedance cup 47d coaxially arranged with the supply cylinder 40d provides a gas G at the distal end portion 20 of the electrode 2.
, And surrounds the arc a generation region to shut off the outside air, thereby preventing a bad influence caused by touching the outside air.

[0004]

However, the conventional welding torch 1D is of a type in which one kind is selected in advance as a shielding gas G guided around the arc a due to its structure. In the following cases, there is room for improvement. That is, using the welding torch 1D, in a production line or the like, for example, in order to efficiently weld and reduce the production cost, a normal arc welding speed (in the case of aluminum, approximately 600 mm / min.)
When welding at a faster arc welding speed (in the case of aluminum, approximately 1500 mm / min.), It is necessary to increase the heat input density (increase the current density by increasing the current density) for the member to be welded. In addition, it is necessary to improve the rigidity of the arc (hardness of arc fluctuation, so-called arc stability).

[0005] However, when He (helium) is used as a shielding gas of the conventional welding torch 1D, for example, the shape of the arc a is substantially vertical (see FIG. 8).
(See arrow a1), the heat input density can be increased, but the rigidity of the arc is low. Also, A
When r (argon) is used, the arc shape becomes divergent toward the workpiece 60d (see the arrow a2 in FIG. 8), so that the arc is excellent in rigidity, but the heat input density can be increased. Can not.

The heat input density is, for example, about 3 times in the case of He, assuming that the case of Ar is assumed to be 1. The rigidity of the arc is assumed to be, for example, 1 in the case of Ar and compared (the rigidity is proportional to the arc pressure; therefore, the arc is compared with the arc pressure).
/ 3. Therefore, in the conventional welding torch 1D, for example, the above-described condition required for high-speed welding cannot be satisfied because the above-described method uses only one kind of shielding gas such as Ar or He. Can not do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to increase the heat input density with respect to a member to be welded and to obtain the rigidity of an arc (the difficulty of arc wobbling).
It is an object of the present invention to provide a welding torch shield structure which can improve the welding speed and can perform arc welding at high speed.

[0008]

According to the present invention, there is provided a shield structure for a welding torch, comprising: an electrode; first gas guide means for guiding a supplied first gas to a vicinity of a tip of the electrode; And a second gas guiding means for guiding the first gas and the second gas at an arbitrary ratio to be used for welding.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The first gas guide means and the second gas guide means are provided with a cylindrical body having an inner diameter different from each other coaxially, or a cylindrical body having a large inner diameter and a cylindrical body having a large inner diameter. It is possible to use one having a configuration in which a plurality of small-diameter cylindrical bodies (hollow tubes) are circumferentially located at predetermined intervals around an electrode protruding into the hole.

The first gas guiding means supplies the first gas with the second gas.
The gas guiding means guides the second gas to the vicinity of the tip of the electrode. The first gas and the second gas guided near the tip of the electrode
The gas is supplied at an arbitrary ratio and used for arc welding. The first gas and the second gas are mixed in such a manner that different characteristics can be effectively used for each type of gas so that the heat input density and arc rigidity required for high-speed arc welding can be obtained. It is desirable to use as.

For example, Ar is used as the first gas,
When He is used as the gas, the arc generating partial region near the tip of the electrode (hereinafter, referred to as the upper generating region)
Is set so that Ar becomes rich, and He becomes rich in an arc generation part region (hereinafter, referred to as a lower generation region) closer to the member to be welded. The reason for this is that by making the mixture gas rich in Ar exist in the upper generation region of the arc to increase the arc pressure, the rigidity of the arc (hardness of arc fluctuation) can be improved, and the He generation in the lower generation region. This is because high-speed arc welding can be performed because the heat input density to the member to be welded can be increased by the presence of a rich mixed gas.

Further, as the first gas and the second gas,
In addition to the above-mentioned Ar and He, for example, CO _Two, H_Two, O_Two, N
e or a mixed gas obtained by mixing these at appropriate times.
Select according to the contact target member (work) and electrode material
Can be used. Note that the first gas and the second gas are
When mixing at an arbitrary ratio and using for welding, one type for each
Gas (separate types) to the first gas guide means and the second gas
It can be guided near the electrode by gas guiding means,
One or both of the first gas guiding means and the second gas guiding means
From the side of the gas mixture
(Adjusted gas in proportion) to the vicinity of the electrode
Can be.

The shield structure of the welding torch of the present invention can be applied to TIG welding and MIG welding.

[0014]

【Example】

(Embodiment 1) While applying Embodiment 1 of the present invention, a shield structure of a welding torch, to a welding torch 1A shown in FIG.
A description will be given of the case where the welding torch 1A is held in the vertical direction and the workpieces 60, 60 using two metal plates as welding target members are horizontally butt-welded.

The welding torch 1A comprises an electrode 2, a cylindrical torch main body 3, first gas guiding means 4a, and second gas guiding means 5a. The electrode 2 is an electrode made of tungsten and has a guide hole 31 of a collet 31 (contact tip).
The workpiece 60 is melted by the high heat of the arc a generated between the workpiece 60 to be positively charged and the negatively charged workpiece 60 to be welded in contact with the inner peripheral surface of the workpiece 60 to form a welded portion 61. Things.

The cylindrical torch main body 3 is a cylindrical body made of conductive metal. The tubular torch main body 3 has a hole 30 through which the electrode 2 is inserted, and a tip attachment portion 32 to which a collet 31 is detachably attached at the tip. The collet 31 is made of copper, is a cylindrical body having a tapered tip, has a guide hole 310 at a center portion, inserts the electrode 2 into the guide hole 310, and supplies a current transmitted from the torch body 3 to the electrode 2. Is what you do.

The first gas guiding means 4a includes a supply tube 40 for supplying a first shield gas, which is mounted on the outer peripheral surface 33 of the cylindrical torch body 3 so as to coaxially surround it at a predetermined interval, and an insulating tube. A cylindrical body 41, a sleeve 42, a supply passage 46 communicating with the first gas supply source P <b> 1, and a ceramic-made ceramic coaxially arranged around a portion of the electrode 2 protruding from the collet 31 toward the work 60. A first gas guiding high-an cup (hereinafter, referred to as a cup) 47a.

The supply cylinder 40 has a first gas supply passage 44 formed between its inner peripheral surface 43 and the outer peripheral surface 33 of the cylindrical torch body 3 and a closed end 400 near the collet 31 in the circumferential direction. Has a plurality of first gas ejection holes 45 formed therein. The supply passage 46 has a control unit (not shown) for controlling the flow rate and pressure of the first gas G1 supplied from the first gas supply source P1.

A small-diameter tip guide portion 470 is formed in the cup 47a as a shape for facilitating the guide of the first gas G1 ejected from the first gas ejection hole 45 of the supply cylinder 40 to the vicinity of the tip 20 of the electrode 2. Have been. Second gas guiding means 5
a is a supply passage 50 communicating with the second gas supply source P2;
A second gas guiding high-angular cup (hereinafter, referred to as a cup) 52 surrounding the cup 47a coaxially at a predetermined interval.

The supply passage 50 has a control unit (not shown) for controlling the flow rate and pressure of the second gas G2 supplied from the second gas supply source P2. The cup 52 is connected to the feeding passage 5.
0, and has a plurality of ejection holes 51 which are opened to face the work 60 side and eject the second gas G2, and are provided between the ejection holes 5 and the outer peripheral surface 472 of the cup 47a.
A second gas supply passage 53 for guiding the second gas G2 from 1 to the vicinity of the tip 20 of the electrode 2 is formed.

Here, the welding torch 1A is a cup 4
The gas outflow portion cross-sectional area ratio between the cup 7a and the cup 52 is
1: 8 and Ar as the first gas G1
Is set at 2 liters / minute, and the flow rate of He as the second gas G2 is set at 24 liters / minute. In the welding torch 1A thus configured, the first gas G1 is supplied from the first gas supply source P1, and the second gas G2 is supplied from the second gas supply source P2 at the same timing.

That is, the first gas from the first gas supply source P1
The gas G1 is supplied to the first gas guiding means 4 through the supply passage 46.
After being supplied to the first gas supply passage 44a, the gas is ejected from the first gas ejection hole 45 and is guided to the vicinity of the tip 20 of the electrode 2 by the cup 47a. On the other hand, at the same time, the second gas G2 from the second gas supply source P2 is
The gas is ejected from the second gas ejection hole 51 through the supply passage 50 of the gas guiding means 5a, and is guided to the vicinity of the tip 20 of the electrode 2 by the second gas supply passage 53 formed by the cup 52 and the cup 47a. You.

Then, the first gas G1 and the second gas G2 become a mixed gas and shield around the arc a.
At this time, the mixed gas is rich in Ar (90% or more of Ar: 10% of He) in the upper generation region a10 (see FIG. 1).
And He in the lower generation area a11 (see FIG. 1).
Is rich (Ar is less than 10%; He is 90% or more). The reason is that the first gas G1 and the second gas G2 are not sufficiently mixed in the upper generation region a10, so that the gas has a composition close to the first gas G1, whereas the lower generation region a11 (FIG. This is because the first gas G <b> 1 and the second gas G <b> 2 are sufficiently mixed by the plasma stream.

In the upper generation region a10, the current density is increased due to the rich Ar, so that the pressure of the arc a is high and the rigidity of the arc a can be maintained. Further, in the lower generation region a11, the divergent spread of the arc a can be appropriately suppressed due to the rich He, and the shape of the arc a becomes substantially bell-shaped, so that the heat input density can be increased.

As described above, according to the shield structure of the welding torch 1A of the first embodiment, it is possible to increase the heat input density to the workpiece 60 required for high-speed arc welding.
In addition, even when the heat input density is high, the rigidity of the arc a can be maintained. Therefore, since welding conditions that enable high-speed arc welding can be satisfied, the beat is not generated in the welded area 61, and in the case of aluminum,
Arc welding can be performed at a high speed of about 1500 mm / min or more, and good welding quality can be obtained.

In the case of the first embodiment, Ar is used as the first gas G1 guided to the first gas guide means 4a, and He is used as the second gas G2 guided to the second gas guide means 5a. In the above, the case where Ar and He are mixed in the arc a, and a mixed gas in which Ar is rich in the upper generation region a10 and a mixed gas in which He is rich in the lower generation region a11 is shown. Instead, the types of gases used as the first gas G1 and the second gas G2 and the mixing ratio thereof can be variously set depending on the purpose. For example, as the first gas G1, a mixture of He and Ar mixed in a ratio of less than 30%: 70% or more in advance and having a rich Ar can be used.

(Modification) Welding torch 1A of Embodiment 1
Instead of forming the tip guide portion 470 on the cup 47a, as a modified example, a shape in which the diameter is narrowed down to the tip side of the cup 52b of the second gas guiding means 5b as in a welding torch 1B shown in FIG. A tip guide 520 may be formed.

[Experimental Example] The welding torch 1A of the first embodiment.
In order to confirm the effect of using the method, an experimental example in which arc welding is performed at high speed by the non-consumable electrode type arc welding method under the following conditions will be described. (Arc welding conditions in experimental example) Tungsten electrode 2: φ3.2 mm, tip apex angle 45 °,
2% La ₂ O ₃ containing (Tungsten electrode 2 is new and its tip is polished in a conical shape at the beginning of the experiment to make the tip apex angle 45 °.) Square wave AC pulse: f = 10 Hz Average current: 150 A (ampere) Arc length: 5 mm Welding speed: 70 cm / min Shielding gas: Ar is 2 liter / min as the first gas G1 from the first gas guide means 4a, and the second gas guide means 5
He guided 24 liters / min as the second gas G2 from a to the vicinity of the arc a, and formed a mixed gas (mixing ratio of Ar and He was 1:12).

Test piece shape: The material shown in FIGS. 3 and 4 is AD
Elliptical hole in the center at C12 (major axis 80 mm x minor axis 50 mm)
Rectangular plate (length 110 mm x width 70 mm x thickness 16 mm) 63 and an oval pipe with a material of 3003 and thickness 2 mm (major axis 80 mm x minor axis 50 mm x length 200 m)
m) 64 was used. (Experimental result) The thick plate 63 was changed according to the arc welding conditions.
The experiment of arc welding the entire circumference of the boundary 65 with the end of the elliptical pipe 64 at a depth of 8 mm of the inner peripheral surface 630 of the elliptical hole was repeated until the bead slip occurred due to the wear of the tungsten electrode 2. The number of times of use, the penetration depth d of the thick plate 63 (see FIG. 5), and the following bead displacement occurrence rate were confirmed. The results are shown in Table 1, and FIG. The results obtained by arc welding with a conventional torch are shown in comparison. As a result of the experiment, the penetration depth d at which bead displacement does not occur in a test piece arc-welded with the welding torch 1A of Example 1 using the two kinds of shielding gases of Ar and He in the above mixing ratio is 0.9. 〜1.4 mm.

On the other hand, an average current of 180 A (ampere) was obtained by using one kind of Ar alone as a shielding gas.
Except that the penetration depth d of the test piece arc-welded under the same experimental conditions as the welding torch 1A does not cause a bead deviation, is 0.4 to 0.7 mm, and the welding torch 1A of Example 1 According to the case, it was found that the penetration was deep and the welding was performed more reliably.

It should be noted that the arc welding was performed using two types of gas, Ar and He, each having different characteristics as the shielding gas under the condition that the depth of melting by the arc was the same. 1 with only Ar as gas
The limit number of times of welding in the conventional case where arc welding is performed using the type is greater by 10 times as shown in FIG. In addition, as shown in FIG.
, The average current could be reduced by about 15%, and the life of the tungsten electrode 2 could be extended by about 40%.

(Embodiment 2) A shield structure of a welding torch according to a second embodiment of the present invention will be described with reference to a welding torch 1C shown in FIG. The welding torch 1C is different from the welding torch 1A of the first embodiment in that a first gas guide 4c and a second gas guide 5c are used instead of the first gas guide 4a and the second gas guide 5a. , And the same as in the first embodiment.

The structure of the first gas guiding means 4c is the same as that of the first gas guiding means 4a except that the first gas guiding means 4c does not have the cup 47a. The second gas guiding means 5c includes a second gas supply source P2
And a second gas guide high-impedance cup which functions to guide the first gas G1 to the vicinity of the tip end 20 of the electrode 2 as in the case of the cup 47a of the first gas guide means 4a of the first embodiment. (Hereinafter, referred to as a cup) 52c, and a plurality of hollow tubes 51c connected to the cup 52c in a state of being coaxial with the electrode 2 and arranged in the circumferential direction thereof while being in communication with the feed passage 50. , Consisting of.

The hollow tube 51c has an ejection hole 510 at the tip for ejecting the second gas G2 from the second gas supply source P2, and the ejection hole 510 is bent toward the vicinity of the tip 20 of the electrode 2. The end guide section 511 is provided. According to the welding torch 1C of the second embodiment, the welding torch 1A of the first embodiment and the welding torch 1B of the modified example are described.
The same effect can be obtained.

In the first and second embodiments, the case where the shield structure of the welding torch is applied to a non-consumable electrode type arc welding torch is shown. However, the present invention is not limited to this. It can also be applied to torches.

[0036]

According to the shield structure of the welding torch of the present invention, the first gas guide means guides the first gas and the second gas guide means guides the second gas to the vicinity of the tip of the electrode. The first gas and the second gas are supplied at an arbitrary ratio and used for welding. Therefore, the heat input density can be increased, the rigidity of the arc can be maintained even when the heat input density is increased, and the welding conditions required for high-speed arc welding can be satisfied.

Therefore, arc welding can be performed at a high speed without generating a welding beat deviation, and good welding quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a main part of an electrode-type arc welding torch according to a first embodiment of the present invention;

FIG. 2 is a partial sectional view showing a modification of the electrode-type arc welding torch in FIG.

FIG. 3 is a perspective view showing a member to be welded in a usage example when welding is performed at a high speed using the electrode-type arc welding torch in FIG. 1;

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 is an enlarged partial cross-sectional view showing, in an enlarged manner, a state after welding of a portion viewed from the arrow Y in FIG. 4;

FIG. 6 is a comparative diagram showing a comparison between welding limits of the electrode-type arc welding torch of Example 1 and a conventional electrode-type arc welding torch.

FIG. 7 is a partial cross-sectional view showing a main part of the electrode-type arc welding torch according to the second embodiment by partially cross-sectional view;

FIG. 8 is a partial sectional view showing a conventional electrode-type arc welding torch in a partially sectional view.

[Explanation of symbols]

1A, 1B, 1C ... Electrode arc welding torch 2 ... Electrode 3 ... Torch main body 31 ... Collet (contact tip) 4a ... First gas guide means 47 ... High gas cup for first gas guide G1 ... First gas (Ar) 5a ... Second gas guide means 52 ... High gas cup for first gas guide G2 ... Second gas (He) 60 ... Work (member to be welded) 61 ... Welded part a ... Arc a10 ... Arc near the tip of the electrode Generated partial area a11 ... Arc generated partial area on the side closer to the welding target member

Continued on the front page (72) Inventor Masato Asai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Mitsuhiro Ogihara 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (1)

[Claims] An electrode; a first gas guiding means for guiding a supplied first gas to a vicinity of a tip of the electrode;
A second gas guiding means for guiding a gas to the vicinity of the tip of the electrode, wherein the first gas and the second gas are supplied at an arbitrary ratio and used for welding. Welding torch shield structure.