JPH0227993Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a welding device, and particularly to a welding device for automatically TIG welding pipes made of different materials in all positions.

Conventionally, butt welding of different materials, such as stainless steel pipes and chromium-molybdenum steel pipes, has been performed using Inconel wire, but this type of wire is prone to hot cracking, and therefore it is difficult to use a low-input welding method for this type of welding. Heat welding required. Also, since this type of welding requires strict welding heat input control, it is essential to employ automatic welding.

FIG. 1 shows a typical example of a boiler tube panel, which is manufactured by the following procedure.

First, the stainless steel pipes 1 are bent, and each of these steel pipes 1 is assembled into a panel shape as shown in the figure to form a stainless steel pipe panel A.

Next, only this stainless steel tube panel A is subjected to solution heat treatment at a high temperature (approximately 1100°C). Note that simultaneous solution heat treatment of stainless steel pipes and chromium-molybdenum steel pipes is prohibited due to their material properties.

On the other hand, the chromium-molybdenum steel pipe 2 is similarly bent to form the chromium-molybdenum steel pipe panel B.

The stainless steel pipe panel A and the chromium-molybdenum steel pipe panel B thus manufactured separately were
Butt welding is performed at the joints indicated by X and Y in the figure to produce a boiler tube panel as shown.

By the way, in the above-mentioned butt welding, a short pipe 3 of different materials obtained by butt welding a stainless steel pipe 1 and a chromium-molybdenum steel pipe 2 as shown in FIG. 2A is prepared in advance, and the short pipe 3 is As shown in Figure B, it is interposed between the abutting portions of both panels A and B,
Both ends of this were butt welded.

However, according to this method, each joint made of different materials requires welding at three locations a, b, and c, which poses a problem in that the manufacturing cost of the panel increases.

Here, a method of welding the short pipe 3 of different materials is shown in FIG.

First, a stainless steel pipe 1 and a chromium-molybdenum steel pipe 2 are rotatably supported by a rotating device 4, and both 1 and 2 are abutted at part a, and while rotating these steel pipes 1 and 2, a welding torch 5 is used to apply a low current. Automatic downward TIG welding under low heat input conditions such as During welding, in order to further lower the interlaminar temperature, the welding part a is cooled with cooling water jetted from the water cooling nozzle 6, and in order to prevent the welding part a from being oxidized, shielding gas is supplied from the large double shield nozzle 5a of the welding torch 5. We are trying to strengthen the shield by spraying it.

The present invention was developed to effectively solve the above-mentioned problems caused by the conventional welding methods.The purpose of this invention is to directly weld tubes made of different materials, thereby maintaining high quality while creating panels. To provide a welding device that can reduce manufacturing costs.

In order to achieve such an object, the present invention provides a double shield device that spouts shield gas around a welding torch attached to a welding machine head that rotates around the workpiece, and also The gist is that an air cooling device is provided at a position facing the torch.

A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

Figure 4 is a diagram showing the welding state of pipes made of different materials, Figure 5
Figure A is a side view of the welding apparatus according to the present invention, Figure B is a front view of the same, Figure 6 is a perspective view of the cooling nozzle, and Figure 7 is a partially cutaway sectional view of the welding torch.

The configuration of this welding device will be explained based on FIG. 5. In the figure, 11 is an orbital welder head that rotates around the pipes 1 and 2 to be welded (1 is a stainless steel pipe, 2 is a chromium-molybdenum steel pipe). A welding torch 13 is integrally attached to the head 11.

As shown in FIG. 7, a tungsten electrode 14 is provided at the center of the welding torch 13, and a double shield device 15 is provided around the electrode 14. It is composed of a shield nozzle 15a formed around the shield nozzle 15a, and another annular shield nozzle 15b surrounding the shield nozzle 15a.
5b is connected to a shield gas supply device (not shown).

Further, as shown in the figure, an air cooling device 16 is integrally provided at a position facing the welding torch 13 of the head 11, and the cooling device 16 includes a vortex tube 17 (low temperature air generator) and a vortex tube. 17 and a cooling nozzle 19 communicating with the cooling nozzle 19 via a connecting pipe 18.

A gas inlet 17a is provided on the outer periphery of the vortex tube 17 in a tangential direction thereof, and the gas inlet 17a communicates with a compressed air supply source such as an air compressor (not shown). The upper surface 19a of the cooling nozzle 19 is formed into a circular arc shape as shown in FIG.
b opens toward the pipe to be welded 1.

Next, welding work using this welding device will be explained.

When the orbital welder head 11 is driven to rotate, the welding torch 13 and cooling device 16 integrally connected thereto rotate around the pipes 1 and 2 to be welded.

Then, the electrode 14 of the welding torch 13 is energized to perform automatic TIG welding in all positions of the butt weld part a of both steel pipes 1 and 2. At the same time, compressed air flows tangentially into the vortex tube 17 from the gas inlet 17a, the compressed air is separated into cold air and hot air within the vortex tube 17, and the cold air flows through the connecting pipe 18. A spout 19b is introduced into the cooling nozzle 19 through the cooling nozzle 19 and is formed on the upper surface of the nozzle 19.
The water is ejected from the welding area to cool the area around the welded part a.

Since the welded part a is thus cooled by the cold air, the temperature rise of the welded part a is effectively suppressed, and welding defects such as cracks do not occur in the welded part a. Furthermore, since the welded part a is cooled by gas cooling, no post-treatment is required compared to conventional water cooling, and workability, work environment, etc. are significantly improved.

On the other hand, during welding, both shield nozzles 15a, 15 of the double shield device 15 provided on the welding torch 13
Since shielding gas such as argon gas is constantly sprayed twice onto the welded part a from b, even if cooling air blows out and the shielding gas is disturbed, the shielding gas atmosphere in the welded part a is maintained. Oxidation of the weld zone a is effectively prevented, thereby maintaining high weld quality.

Note that the above cooling and shielding are possible not only during welding but also during non-welding.

In the above, since the pipes 1 and 2 made of different materials are joined by butt welding at only one location a as shown in FIG. 4, the conventional method shown in FIG.
Compared to the method that requires butt welding (b and c), the number of welding points can be reduced, thereby making it possible to significantly reduce manufacturing costs.

As is clear from the above explanation, according to the present invention, a double shielding device is provided that spouts shielding gas around the welding torch attached to the welding head that rotates around the workpiece, and Since the air cooling device is provided at a position facing the welding torch, pipes made of different materials can be directly welded, and manufacturing costs can be reduced while maintaining high product quality.

[Brief explanation of drawings]

Figure 1 is a front view of the boiler tube panel, Figure 2
Figure A is a side view of a short pipe of a different material, B is a diagram showing a conventional welding method using a short pipe of a different material, Figure 3 is a side view of a conventional welding device, and Figure 4 is a side view of a welding device of the present invention. Figure 5A is a side view of the welding device according to the present invention, Figure 5B is a front view of the same, Figure 6 is a perspective view of the cooling nozzle, and Figure 7 is a diagram of the welding torch. FIG. 3 is a partially cutaway side view. In the drawings, 1 is a stainless steel tube, 2 is a chromium-molybdenum steel tube, 11 is an orbital welder head, 13 is a welding torch, 14 is a tungsten electrode, 15 is a double shield device, 15a and 15b are shield nozzles, and 16 is an air cooling device. device, 17 is a vortex tube, 19 is a cooling nozzle, a,
b and c are parts to be welded.

Claims (1)

[Scope of utility model registration request] A double shield device is provided to eject shielding gas around a welding torch attached to a welding machine head that rotates around the workpiece, and an air cooling device is provided at a position facing the welding torch on the welding machine head. A welding device characterized by comprising: