JPS63215391A - Welding method for gas turbine combustion cylinder - Google Patents

Abstract

PURPOSE:To obtain the weld zone high in its high temp. strength and good in heat transfer by interposing a corrugated sheet between the adjacent end parts of each side shell of the main body of a combustion cylinder by superposing them and effecting a brazing after welding the contact part of the side shell and corrugated sheet by laser beam. CONSTITUTION:In welding the adjacent end parts of each side shell composing the main body of a gas turbine combustion cylinder the adjacent end parts of an outside shell 21 and inside shell 23 are superposed to interpose a corrugated sheet 22 in the gap 20 formed between each other. The outside shell 21 and corrugated sheet 22 are assembled by effecting tack welding 26 adequately. Thereafter this assembly body and laser beam are relatively moved in the circumferential direction to subject the contact part 28 of each side shell 21, 23 and corrugated sheet 22 to spot welding 24. The gap of the weld zone is thereafter subjected to vacuum brazing by coating a brazing filler metal 29 in the gap 27 of the contact part 28. The weld zone high in the high temp. strength, large in the joining area and good in the heat transfer is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for welding a gas turbine combustion tube.

(Prior art) A conventional gas turbine combustion tube will be explained with reference to FIG.
(1) is a combustion cylinder main body, and the combustion cylinder main body (1) is composed of a plurality of side shells that are arranged telescopically in the axial direction and have adjacent ends overlapped with each other. Further, (2) is the overlapping portion of each side shell, and the overlapping portion (2) is sequentially welded by resistance spot welding to form the combustion cylinder main body (1).

(Problems to be Solved by the Invention) Conventionally, as described above, the overlapping portions (2) of the air passage portions of the combustion tube body (1) were sequentially welded by resistance spot welding, so (I) high temperature strength was High. (■) Large bonding area. (In) There was a problem in that it was not possible to obtain a welded part with good heat conduction.

(Means for Solving the Problems) The present invention addresses the above-mentioned problems, and when welding the adjacent ends of each side shell constituting the combustion tube main body of a gas turbine combustion tube, The adjacent end portions of the two are overlapped, a corrugated plate is interposed between them, and each of the side shells, the corrugated plate, and the laser beam are then moved relative to each other in the circumferential direction, so that the relationship between each side shell and the corrugated plate is It is characterized by first welding the contact part and then brazing the gap between the weld parts.

The object of the present invention is high temperature strength. Large joint area. An object of the present invention is to provide a welding method for a gas turbine combustion tube that can obtain a welded portion with good heat conduction.

(Function) As described above, the welding method for a gas turbine combustion tube of the present invention involves welding the adjacent ends of the respective side shells constituting the combustion tube body of the gas turbine combustion tube. They are stacked one on top of the other, a corrugated plate is interposed between them, and each of the side shells, the corrugated plate, and the laser beam are then moved relative to each other in the circumferential direction to weld the contact portions between each of the side shells and the corrugated plate. 2. Next, the gap between the welded parts is brazed to obtain the combustion cylinder body.

(Example) Next, the welding method of the gas turbine combustion tube of the present invention will be described in Section 1.2.
．． This will be explained using an example shown in FIG.

(21) is the outer shell, (23) is the inner shell, (20) is the gap between the outer shell (21) and the inner shell (23),
(22) is a corrugated plate inserted in the same gap (20), (24)
(25) is the vertical joint of the outer shell (21), (28) is the contact area between the corrugated plate (22), the outer shell (2 parts) and the inner shell (23), (29) is the spot weld part, Using brazing filler metal, overlap the adjacent ends of the outer shell (21) and the inner shell (23) to form a gap (20) of 3.6 mm between each other.
Next, in the same gap (20), a corrugated plate (22), that is, a thickness of 1. A corrugated plate (22) having a diameter of 2 mm, a width of 25 mm, a circumferential length of the contact portion (28) of 8.1 mm, and a pitch of 1/48 of the circumferential length is inserted into the gap (20), and the outer shell is (2
1) and the corrugated plate (22) are temporarily welded at about 6 force points in the circumferential direction (see (26)) to ensure that they are assembled together.

A holding jig (not shown) applies force radially from the center of the inner shell (23) to the inner shell (23) and the corrugated plate (22), so that the corrugated plate (22), the outer shell (21) and Inner shell (23
) The gap (27) between the contact portion (28) and the contact portion (28) is maintained at 0.3 mm or less.

Next, these outer shell (21), corrugated plate (22), and inner shell (23) were exposed to a CO2 laser beam (average output: 800 W).

A COt laser beam with a peak output of 1500 W and a lens focal length of 7.5 inches (190.5 mm) is installed 1 mm from the focal point of the lens, and the spot welded part (
24) Protect the inside of the tube with argon gas.

The CO2 laser beam side is protected by helium gas, and then the COZ laser beam, the corrugated plate (22) and the outer shell (
21) and the inner shell (23) in the circumferential direction, each spot weld (24) is welded in a circular welding beat pattern as shown in FIG. 5(I) or in a spiral welding pattern as shown in FIG. 5(n). Weld by beat pattern. Next, Figure 5 (I[
The case where circular welding (24a) in FIG. 4 is performed using the C-line welding beat pattern of I) will be described. In this case, the outer shell (21) and the corrugated plate (22) are lap-welded, and then the corrugated plate (22) and the inner shell (23) are lap-welded. Once the lap joint welding at one location is completed, a second lap joint welding is performed, and thus a total of eight lap joint welds are performed. Lap joint welding at each location was performed using the CO2 laser beam, and when one round of welding was completed.

Reduce the output to 300W and perform crater treatment. Also, in the case of the same Figure 4 and the cases of the above-mentioned Figures 1 to 3, after welding is completed, the combustion cylinder body (see (1) in Figure 6)
Remove from the holding jig, pickle, dry, and mix powdered NI solder and flux to form a paste (brazing filler metal).
29) to the gap (27) at the contact area (2nd day) between the corrugated plate (22) and the outer shell (21) and inner shell (23) so that the leg length is about 2 mm, and then vacuum braze it. conduct. At this time, the brazing filler metal (29) penetrates into the gap (21) due to the cleaning action of the flux and the capillary phenomenon of the brazing filler metal, and solidifies while forming an alloy with Hastelloy X.

During welding with the CO2 laser beam, the focused 00
The g laser beam penetrates the upper shell (21) and passes through the corrugated plate (
22) and the upper shell (21) and the inner shell (23), the molten metal is stirred by the energy of the laser beam, and the corrugated plate (22) is connected to the upper shell (21).
) and welded to the inner shell (23). In this condition.

When the CO2 laser beam is moved in the circumferential direction, the corrugated plate (2
2), the upper shell (21), and the inner shell (23) have an increased welding area and are firmly welded to each other. The welding pattern at this time is as shown in Fig. 5 (I) (II).
In the lap joint weld, thermal energy is not locally accumulated, and approximately the same weld depth can be obtained at the locations where the CO and laser beams have passed.

In addition, when performing circular welding (24a) in Figure 4 using the C-line welding beat pattern in Figure 5 (I[I), two revolutions are made by rotating the outer shell, inner shell, and corrugated plate once. Welding (24a) is completed. That is, the focused C Oz
A laser beam penetrates the upper shell (21).

The contact portion (28) between the corrugated plate (22) and the upper shell (21) and inner shell (23) is melted to form a weld bead;
Once the CO2 laser beam reaches the end of the contact (28).

Since the corrugated plate (22) is separated from the upper shell (21) and the inner shell (23), the double joint welding is completed, and from then on, only the outer shell (21) is melted and a bead is formed.

When the next contact part (28) is reached, the corrugated plate (22) is reached again.
) and the contact portion (2) with the upper shell (21) and the inner shell (23)
8) is melted to form a weld bead. By repeating this process, the circular welding (24a) is completed. When this is completed, the beam energy is lowered and the beam is rotated once, thereby reducing the size of the crater.

Note that the depth of penetration by the laser beam changes more greatly depending on the focus position and the workpiece position, so the height position of the combustion tube body is detected by a sensor, etc., and the workpiece is raised and lowered to approximate the penetration depth. I try to keep it constant. Furthermore, since lap joint welding using a laser beam does not allow a large joint area to be obtained, the joint area is increased by brazing.

In addition, a special brazing method is used to minimize welding deformation. For brazing, a powdered brazing filler metal mixed with flux is placed on the lap joint welding area using a brazing process for 10 minutes.
This was done by heating to 1050'C for 1 hour in a 'to'rr atmosphere.

(Effects of the Invention) As described above, the welding method for a gas turbine combustion tube of the present invention involves welding adjacent ends of each side shell that constitutes the combustion tube body of a gas turbine combustion tube. The parts are overlapped, a corrugated plate is interposed between them, and each of the side shells, the corrugated plate, and the laser beam are moved relative to each other in the circumferential direction, so that the contact portion between each of the side shells and the corrugated plate is Since the combustion cylinder body is obtained by welding and then brazing the gaps between the welds, it has high high-temperature strength. Large joint area. Furthermore, there is an effect that a welded part with good heat conduction can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the gas turbine combustion tube welding method according to the present invention, FIG. 2 is a longitudinal side view thereof, FIG. 3 is a longitudinal front view thereof, and FIG. 4 is another embodiment. 5(1), (II) and (III) are explanatory views showing each welding beat pattern, and FIG. 6 is a side view showing the combustion tube main body of the gas turbine combustion tube. (1)... Combustion tube main body, (2)... Overlapping part, (2
1) ...outer shell, (22) ...corrugated plate,
(23) ...inner shell. (27)...Pa gap, (2B)...Contact part, (2
9) ...brazing material.

Claims (1)

[Claims] When welding the adjacent ends of the side shells constituting the combustion tube body of the gas turbine combustion tube, the adjacent ends of the side shells are overlapped, a corrugated plate is interposed between them, and then the side shells are welded together. and a gas turbine characterized in that the corrugated plate and the laser beam are moved relative to each other in the circumferential direction to weld the contact portions between each side shell and the corrugated plate, and then the gaps between the welded portions are brazed. How to weld a combustion tube.