JPS5948701B2 - Filler wire oxide film removal welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filler wire oxide film removal welding method suitable for, for example, MIG welding of aluminum and aluminum alloys and Teig welding (semi-automatic Teig welding, automatic Teig welding) in which filler wire is automatically supplied. .

When welding aluminum alloys, etc., MIG welding is very efficient because it has good workability, high welding efficiency, and can increase welding speed.

However, a filler wire of fine wire (0.8 to 0.6 φ) is generally used, and an oxide film is formed on the surface of this filler wire during drawing during the manufacturing process. The component of this oxide film is Al. O. , Al. O.・H. O, Al, O, ・3H
. Since it is composed of O, etc., it decomposes during arc welding to become Ho, which enters the weld metal and generates blowholes. This results in MIG welding that uses filler wire and semi-automatic TIG welding that automatically supplies filler wire.
This is a fatal drawback of automatic Teig welding. Therefore,
For welds that require high quality and cannot tolerate defects such as blowholes, the Teig welding method, in which short filler wire is manually supplied, must be used.

However, this Teig welding method is entirely manual and has very poor workability, and the welding speed is slow, making it inefficient. In addition, the amount of heat input increases locally, and the generation of strain also increases compared to MIG welding. For this reason, there is a long-awaited development of an efficient MIG welding method that does not cause defects such as blowholes. The purpose of the present invention is to prevent the occurrence of blowholes and to enable highly efficient and high quality welding, especially in the welding of aluminum alloys that are prone to defects such as blowholes, such as aluminum alloy vehicles and TO plants. That is. In order to achieve the above object, the present invention automatically removes the oxide film on the surface of the filler and wire by the cleaning action of the arc in MIG welding, semi-automatic TIG welding, automatic TIG welding, etc. in which filler wire is automatically supplied, and By performing welding using filler wire from which the oxide film has been removed, high quality weld metal without defects such as blowholes can be obtained.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an example of the use of the present invention in MIG welding. A DC power source 1 is connected to a base material 19 to be welded and a torch power supply section 4 . The base material 19 is connected to the negative side of the DC power source 1, and the torch power supply section 4 is connected to the positive side of the DC power source 51, so that they are connected in a so-called reverse polarity. The filler wire 8 is fed from the wire reel 7 by a wire straightening roller 9 and a feed roller 10, and further fed to the recontact tip 5 through a guide tube 11. The present invention removes the oxide film on the surface of the filler wire 8 thus fed between the wire straightening roller 9 and the feed roller 10 by the cleaning action of an arc. The mechanism for removing the oxide film on the surface of the filler wire 8 uses the general Teig welding method, and the positive side of the DC power source 2 is connected to the electrode (tungsten electrode) 14, and the negative side of the DC power source 2 is connected to the wire. It is connected to the filler wire 8 via the straightening roller 9, and is connected in so-called reverse polarity.

The high frequency generating power source 3 is provided to facilitate the generation of an arc 16 between the electrode 14 and the filler wire 8. The area around the arc 16 is from inside the nozzle 15. shield gas 1
As step 7, for example, argon gas or the like is made to flow out. In addition,
Since the purpose of this arc 16 is only to remove the oxide film on the surface of the filler wire 8, it is necessary to select welding conditions within a range that does not melt the filler wire 8, and a welding current of approximately 10 to 20 A is sufficient. . Therefore, the torch section consisting of the electrode 14, nozzle 15, etc. may be lightweight and small. When the shielding gas 17 is supplied to generate an arc 16, the oxide film on the surface of the two-fiber wire 8 is removed by the cleaning action of the arc 16, and the filler wire 8 is fed into the guide tube 11 by the feed roller 10, and is Electricity is supplied to generate an arc between the base metals 19 and form droplets 12.

At this time, for example, argon gas or the like is flowed out from the nozzle 6 as the shielding gas 133, and the surface of the base material 19 is cleaned by the arc to form a cleaning portion 21. Here, since the oxide film of the filler wire 8 has been removed, the components of the oxide film (Al2O3, Al2
(O3.H2O, Al2O3.3H20, etc.), therefore, it is not decomposed by the high heat of the arc and does not generate H2, etc., and does not cause blowholes. Therefore, the weld metal 20 can be made of high quality components and free from defects such as blowholes. In FIG. 2, two sets of Teig welding torches are installed facing each other, and the oxide film can be removed more efficiently than in FIG. 1.

Note that three sets (arranged at every 120°) or four sets (arranged at every 90°) of welding torches can also be used. Since the present invention is as described above, it is possible to weld high-quality aluminum alloys, etc., by completely eliminating blowholes caused by H2 generated by the decomposition of the oxide film on the surface of the filler wire.

Furthermore, MIG welding can be applied to locations where Teig welding is used due to the quality of welding.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional explanatory diagram showing an embodiment in which the present invention is applied to MIG welding, and FIG. 2 is a partially cross-sectional explanatory diagram showing another embodiment. 1, 2...DC power supply, 3...High frequency power source, 4...Torch power supply section, 5...
Contact tip, 6... Nozzle, 7...
... Wire reel, 8 ... Filler wire, 9.
...Wire straightening roller, 10...Feeding roller, 14...Electrode, 15...Nozzle, 19...Base material.

Claims (1)

[Claims] 1. In a gas-shielded arc welding method in which filler wire is automatically supplied, an oxide film on the surface of the filler wire is removed by the cleaning action of the arc, and welding is performed using the filler wire from which the oxide film has been removed. A welding method for removing an oxide film on filler wire, characterized by performing the following steps. 2. The oxide film removal welding method for filler wire according to claim 1, wherein an arc cleaning action is performed using a Teig welding torch.