JP3023638B2 - TIG welding torch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torch for TIG welding used in a welding operation.

[0002]

2. Description of the Related Art A conventional TIG welding torch has a structure as shown in FIGS.

In FIG. 2, reference numeral 1 denotes a torch main body, which is formed by a substantially cylindrical metal member 2 and a substantially cylindrical insulating member 3 surrounding the metal member 2. Reference numeral 4 denotes a non-consumable electrode inserted into the center of the torch body 1, reference numeral 5 denotes a collet for contacting and holding the non-consumable electrode 4, reference numeral 6 denotes a collet body for contacting and holding the collet 5, and reference numeral 7 denotes a shield gas for supplying a welding gas to a welding portion. Nozzle.

FIG. 3 shows a collet body 6, and the material of the collet body 6 is copper or a copper alloy excellent in high-temperature hardness, for example, chromium copper in consideration of electric conductivity and heat conductivity. Further, the collet body 6 was used as it was without the surface treatment.

[0005]

In the TIG welding torch using the non-consumable electrode having such a conventional configuration, in the welding operation, the non-consumable electrode 4 is only required from the welding power supply circuit immediately after the arc start. There is no thermoelectron emission capability, and the arc generation point is where the oxide film on the surface of the non-consumable electrode 4 exists. At the first moment immediately after the arc start, an arc generating point is generated at the lower end of the non-consumable electrode 4, that is, at a position closest to the base material which is the work to be welded. Moves around in search of a certain point of another oxide film, crawls upward on the surface of the non-consumable electrode 4, and the arc generating point moves to the collet body 6. However, since there is a distance from the collet body 6 to the base material, an arc directed from the collet body 6 to the base material becomes unstable, resulting in a problem that the arc start fails.

Further, when an arc is generated from the collet body 6, there is a problem that the arc causes the arc generating surface of the collet body 6 to be worn and damaged, and that the collet body 6 must be finally replaced.

[0007] The present invention solves the above-mentioned problems, and the T
An object of the present invention is to provide a TIG welding torch capable of stabilizing and ensuring arc startability, which is important in IG welding, and improving the life of a collet body.

[0008]

In order to achieve the above object, the present invention includes a portion of a collet body of a TIG welding torch using a non-consumable electrode which is closest to a base material. It has a ceramic coating on the outer surface.

[0009] In the collet body ,
The outer surface including the approaching portion is plated with a metal having a work function larger than the work function of the non-consumable electrode.

[0010]

In the above construction, the base material of the collet body is
The ceramic electrically insulating decorated with an outer surface including a portion which is also approached, even crawl up the arc during arc start toward the non-consumable electrode upper generation point of the arc towards the base material can move the collet body It not, toward jar arc to the base material failure of the arc start is no longer forced to occur from non-consumable electrode. Since no arc is generated from the collet body toward the base material, wear of the collet body due to the arc is eliminated.

In the collet body , the base material is
The outer surface including the approaching part is plated with a metal having a work function larger than the work function of the non-consumable electrode (a value indicating the difficulty of emitting electrons from the metal, and it is difficult to emit electrons when the work function is large). by subjecting it was, for arc at the time of arc start is also crawls up toward the non-consumable electrode top, the larger of the plated metal work function than non-consumable electrode mother
Generation point of the arc toward the wood is difficult to move the collet body,
The arc toward the base metal must be generated from the non-consumable electrode, and the failure of the arc start is eliminated. Since the arc is hardly generated from the collet body, the collet body due to the arc is hardly worn and damaged.

[0012]

An embodiment of the present invention will be described below with reference to FIG.

Since the structure other than the collet body is the same as that shown in the conventional example, the description is omitted.

(Embodiment 1) FIG. 1A shows a first embodiment, in which a collet body 11 is made of copper or a copper alloy excellent in high-temperature hardness, for example, chromium copper in consideration of electric conductivity and heat conductivity. The surface of the tip is coated with ceramic 12.

In the above configuration, if the oxide film of the non-consumable electrode 4 is destroyed at the time of arc start, the arc generating point runs around in search of a certain point of another oxide film in the same manner as described in the conventional example. Although creeps over the surface of the non-consumable electrode 4 upwards, since the ceramic 12 coated on the outer surface of the tip portion of the collet body 11 is an electrical insulator, generation point of the arc towards the base material collet body 11 cannot move to, so the arc is non-
Since it must be generated from the consumable electrode 4, the failure of the arc start is eliminated. Since no arc is generated from the collet body 11 toward the base material, wear and damage of the collet body 11 due to the arc are eliminated, and the life of the collet body 11 can be extended.

In this embodiment, the collet body 11
In the above description, only the surface of the tip portion is coated with the ceramic 12, but the coating may be applied over the entire outer surface.

(Embodiment 2) FIG. 1B shows a second embodiment, in which a collet body 11 is provided.
Is formed of a copper alloy of the same material as that shown in the first embodiment. And most of the collet body
The outer surface of the near portion is provided with a metal plating coating having a work function larger than that of the non-consumable electrode 4.

When the non-consumable electrode 4 is made of tungsten, the work function of tungsten is 4.54 cV. Therefore, the metal plating coating 13 having a work function larger than that is, for example, gold (work function 4. 89 eV) and nickel (work function 4.96 eV).

In the above configuration, as in the case of the conventional example, even if the arc crawls upward on the surface of the non-consumable electrode 4 at the start of the arc, the plating coating 13
Has a larger work function than the non-consumable electrode 4, so that the arc generating point is less likely to move to the collet body 11, and the arc is non -consumable.
Since it must be generated from the consumable electrode 4, the failure of the arc start is eliminated. Further, since arc is hardly generated from the collet body 11, wear of the collet body 11 due to the arc is hard to occur, and the collet body 11 is hardly damaged.
Life can be extended.

In this embodiment, the collet body 11
Although the description has been given of the case where the entire surface is plated, the plating may be performed only on the outer surface of the tip portion of the collet body 11. That is, the collet body 11
Surface that includes the outer surface of the part closest to the base metal
The purpose of the present invention can be achieved by plating.
it can.

Japanese Utility Model Application Laid-Open No. 63-47074 discloses a configuration of a ceramic-coated metal welding nozzle. This configuration has a nozzle coated with ceramic to dissipate heat. The purpose is to improve the adhesion of spatter
The idea of the present invention of applying a ceramic coating to the collet body to eliminate arc start failure is not suggested.

Japanese Utility Model Application Laid-Open No. 63-16575 discloses a TIG welding torch in which a ceramic nozzle for supplying a shielding gas is formed integrally with an electrode collet in advance. The purpose of the present invention is to reduce the radiation at the tip of the welding torch by eliminating the need for a conventionally used insulating tape and cooling water pipe, and the idea of the present invention is not suggested as in the above-mentioned case.

[0023]

As is apparent from the above description, according to the present invention, the outer surface of the collet body is coated with a ceramic coating, or the surface of the collet body is not erased.
The metal is plated with a work function higher than the work function of the wear electrode.
Even if crawling toward the upper part of the non-consumable electrode, the arc generating point cannot move to the collet body, and the arc has to be generated from the non-consumable electrode, so that the failure of the arc start is eliminated. Thereby, TI using non-consumable electrode
Arc startability, which is important in G welding, can be stabilized and ensured.

Further, since no arc is generated from the collet body, wear and damage of the collet body due to the arc are eliminated, and the life of the collet body can be extended.

[Brief description of the drawings]

1 (a) is a side sectional view of a main part of a TIG welding torch according to a first embodiment of the present invention; FIG. 1 (b) is a side cross sectional view of a main part of a TIG welding torch of the second embodiment;

FIG. 2 is a side sectional view of a conventional TIG welding torch.

FIG. 3 is a side sectional view of the main part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Torch main body 2 Metal member 3 Insulating member 4 Non-consumable electrode 5 Collet 11 Collet body 12 Ceramic 13 Plating coating

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-14139 (JP, A) JP-A-3-225727 (JP, A) JP-A-1-258870 (JP, A) JP-A-55-139 68187 (JP, A) JP-A 1-172468 (JP, U) JP-A 63-62283 (JP, U) JP-A 55-33658 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23K 9/29 B23K 9/067

Claims (2)

(57) [Claims] A torch body formed of a substantially cylindrical metal member and a substantially cylindrical insulating member surrounding said metal member;
A collet that holds a non-consumable electrode located at the center of the torch body, and a collet body that is held in contact with the metal member to contact and hold the collet, including a portion of the collet body closest to a base material. A torch for TIG welding, wherein a ceramic coating is applied to the outer surface. 2. A substantially cylindrical metal member and surrounding said metal member.
A torch body formed of a substantially cylindrical insulating member,
Holds a non-consumable electrode located at the center of the torch body
A collet and the collet held in contact with the metal member.
A collet body for contacting and holding the work piece , and having a work function larger than the work function of the non-consumable electrode on an outer surface including a portion closest to the base material in the work body. A torch for TIG welding, which is plated with metal.