JPS62104683A - Welding torch - 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 [Field of Industrial Application] The present invention relates to a welding torch used for welding, particularly for MIG or MAG welding equipment.

[Prior art and its problems]

For example, the MIG welding method, which has traditionally been widely used,
Welding involves generating an arc between the metal wire that forms the consumable electrode and the object to be welded while surrounded by an inert gas such as carbon dioxide or argon, and melting both the wire and the object by the arc heat. This type of welding device is designed to form a joint, and as illustrated in FIG.
It is comprised of a welding torch for performing welding operations on the object Y to be welded, a gas regulator G, a wire and gas controller C1, a power source B, and the like.

Among these, the welding torch T (also referred to as a welding gun) is a cylindrical body that delivers an inert gas, and is equipped with a copper tip S inside to energize a wire W, which is one electrode.
In addition, the nozzle N, which is made of copper or a modified alloy and has a vibrator shape with an outer diameter of about 15 to 50 mm, is exposed to high temperatures associated with the arc during welding and is melted at the tip so that the inert gas and the wire W can be projected. A part of the welded object Y and the wire W that have been welded fly away. If some of these blown particles adhere to the nozzle N, not only will it cause problems such as blocking the holes H from which inert gas comes out, but the blown particles that have gradually accumulated on the inner wall of the hole H in the nozzle N will cause the wire to Comes into contact with W. Therefore, an electric path is formed from the wire W forming one electrode to the nozzle N, and when welding, an electric path is formed not only from the wire W protruding from the nozzle N but also between the nozzle N and the object Y to be welded. Occasionally, arcs occur and it is not possible to perform good welding work.
There was a risk of insulation failure. In addition, since the nozzle N itself is made of soft copper or prepared alloy with a low melting point, it may become deformed due to the high heat associated with welding work, and debris may become completely welded to the nozzle, making it impossible to clean or remove it. The actual situation was that it was not possible to perform good welding, which hindered not only safety but also the efficiency of welding work.

[Means for solving problems]

In order to eliminate the drawbacks of the conventional welding torches used for MIG welding and MAG welding, the nozzle is made of silicon nitride ceramic, and the nozzle surface is coated with a boron nitride film. shall be.

〔Example] Embodiments of the present invention will be specifically described below with reference to the drawings.

Fig. 2 is an enlarged cutaway view of the nozzle n constituting the torch t according to the present invention. The wire W, which is made of silicon ceramic and has a tip S that guides the wire W and conducts electricity, protrudes from the tip of the nozzle n during welding operation. The wire W protrudes from the hole and emits an inert gas such as carbon dioxide, which acts to surround and protect the area to be welded. The nozzle n is screwed onto the torch t in such a way that it can be separated from the line segment F and removed.

By the way, as mentioned above, the nozzle n related to the wood block is made of a cylindrical body made of silicon nitride ceramic, but the method for manufacturing the cylindrical body having such a shape is to include a metal fitting with a predetermined external shape. Silicon nitride raw material powder mixed with a binder, etc. is filled into a mold, molded from the outside by isostatic press, and then fired in a high temperature atmosphere of 1°500-1,900°C. obtained by. In this way, the nozzle n made of silicon nitride ceramic has a high hardness (HRA8'5~
95), bending strength 3. OOO~8,000Kg/c
It has excellent insulation properties, with an electric volume resistivity of 109 to 1014, and has great heat resistance and mechanical strength, with a maximum usable temperature of 1200°C.

Moreover, in addition to its high heat resistance, it has no affinity with metals8, so it is less likely to react with molten iron that blows away during welding. If the surface of the silicon nitride ceramic material is rough, the blown metal (iron) will be caught and adhered to the micro protrusions on the surface, resulting in surface roughness, especially on the inner wall surface and outer peripheral surface of the hole. As a result of various experiments, it was found that the adhesion of blown-off metal was particularly reduced when polished to Rmax5S or less.

Next, the nozzle n is formed from silicon nitride ceramic as described above, and the surface roughness on the inner wall surface and outer peripheral surface of the hole is adjusted to R.
A boron nitride film B was deposited on the material that had been polished to a maximum of 5s. The boron nitride film B can be deposited by known film forming methods such as CVD (chemical vapor deposition), sputtering, ion blasting, and spraying. The thickness t of the boron nitride film B to be deposited is also related to the surface roughness of the nozzle n, but it is preferably 70μ or less, preferably 50μ or less, and thicker. If so, it tends to peel off from the surface of the nozzle n at high temperatures, making it impractical.

Therefore, the thickness t is applied to the nozzle surface with surface roughness Rmax5s.
A boron nitride film B with a thickness of about 30 to 50μ is deposited;
When a silicon nitride ceramic nozzle whose surface was polished to 53 degrees without the boron nitride film B was used in actual welding work, the results shown in Table 1 were obtained.

〔Effect of the invention〕

As mentioned above, MIG (or M A, G
) The nozzle that forms the welding torch used in the welding equipment is made of a secret silicon nitride ceramic material that has no affinity with molten metal, has high heat resistance and strength, and has electrical insulation properties, and Since a boron nitride film is applied to the
The nozzle hole does not become thermally deformed due to the high heat during welding, and the life of the nozzle is approximately five times longer than that of conventional nozzles made of metal such as copper. It can be removed very easily. As a result, not only is it possible to perform manual welding work, but also automatic welding equipment (contact robots) can perform stable and homogeneous welding over a long period of time without having to frequently replace the nozzle. Welding equipment can be brought to bear.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing an example of a general welding apparatus using a welding torch, and FIG. 2 is an enlarged cutaway view of only the nozzle constituting the welding torch according to the present invention. FIG. 3 is a partially enlarged view of section A in FIG. 2. R: Wire reel T, t: Welding torch S, s: Chisob N, n: Nozzle W, : Wire B, : Boron nitride film

Claims (1)

[Claims] A cylindrical body for introducing an inert gas is provided with a tip for supplying electricity inside the cylindrical body, and a nozzle made of silicon nitride ceramic is provided at the tip configured to feed a metal wire through the tip. A welding torch characterized by having a boron nitride film deposited on its surface.