JPS62156073A - Welding method for tubular body made of stainless steel - Google Patents

Abstract

PURPOSE:To curtail the expense required for a welding work by a simple means, by placing a balloon on both sides of a welding end edge of a tubular body and expanding this balloon, and enclosing an inert gas into a space which has been formed by the balloon and the tube wall, and executing the welding. CONSTITUTION:A double type balloon 41 is provided on both sides by placing end edges 31a, 32a to be welded of tubular bodies 31, 32 between. A compressed air is supplied to two balloons 41a, 41b from a compressed air supply source 42 and the balloons 41a, 41b are expanded, and its outside peripheral surface is pressed against the inside peripheral surface of the tubular bodies 31, 32 and sealed. An inert gas such as an Ar gas, etc. is supplied from a supply source 44 and filled in a closed space D which has been formed by the balloon 41a and the tubular bodies 31, 32. In this state, the outside periphery of the tube of the tube end edges 31a, 32a is welded by inert gas arc welding, etc. According to this method, a weld zone of a stainless steel tube can be sealed by a simple means, and also the quantity of use of the inert gas can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of welding two stainless steel tubes by abutting their open edges against each other and welding the same.

"Prior Art" Generally, in order to weld stainless steel pieces together, it is necessary to create an inert gas atmosphere around the welded part. By the way, when welding stainless steel tubes by bringing their open edges into contact with each other, inert gas arc welding is performed from the outside of the tube along the welding line. At this time, the weld line on the outer circumference of the tube can be made into an inert gas atmosphere by spraying inert gas, but the weld line on the inner circumference of the tube can be sprayed with inert gas. I can't do anything. Therefore, the interior of the tube is filled with inert gas in advance before welding is performed.

Conventionally, a method as shown in FIG. 2 is known as a method for welding such a stainless steel tube body. This method is for welding 'fjt el lla' of the stainless steel tube II and the end Qj12a of the stainless steel tube 12. In this method, in order to fill the insides of the tubes 11 and 12 with inert gas, an end plug I3 is fitted into the end edge 11b of the tube 11 opposite to the edge 11a, and the other tube! A closing plate 14 is provided on the end edge 12b opposite to the end 112a of the second end 112a. And the tube body 11.12,
The space defined by the end Fi l 3 and the closing plate I4 (
The inside of the tube (indicated by A in the figure) is filled with an inert gas (2) through a hole 11c provided in the tube wall of the tube body 11, and welding is performed. In addition, as shown in Figure 3, the stainless steel shank 7
When a tank 22 with a large internal volume is connected to the opposite side of the edge 21a of the body 2I to be welded, the procedure is as follows. That is, a worker enters the interior through the manhole 22a provided in the tank 22 and enters the pipe body 21 of the tank 22.
A closing plate 23 is provided on the side nozzle portion 22b. On the other hand, the edge 12a of the stainless steel pipe body 12 to be welded is melt-hammered thereto.
A closing plate 14 is provided on the edge 12b on the opposite side.

Then, the inside of the tube indicated by B in the figure is filled with an inert gas r, and welding is performed. Furthermore, in this method, a manhole 21a is provided in the tank 22 due to its structure (if it is not possible to go up, a closing means, such as a valve
4, etc., and the inside of the pipe and the tank shown as C in the figure are filled with inert gas I, and welding is performed.

``Problem to be solved by the invention'' By the way, in the method of welding a stainless steel tube shown in Fig. 2 above, the tube! 1. An end plug 13 and a closing plate 1 are installed at the end opposite to the welded part of 12, spaced apart from the welded part of the pipe body.
4 was thrown, so it was necessary to fill a large amount of inert gas into the tube shown by ``H'' in the figure, and there was a problem that it took time to fill the gas. Furthermore, the method of welding the stainless steel tube body shown in FIG. 3 has the problem that a worker must enter the tank 22 and attach the closing plate, which takes time and effort. Ta. Furthermore, in the method of welding stainless steel tubes shown in Figure 1, the inside of the tank 22 is also filled with inert gas, so a larger amount of inert gas is required. However, there was a problem in that it required a longer time to fill the gas.

"Means for Solving the Problems" This invention was made to solve the above problems. Therefore, two balloons are placed on both sides of the two tubes, sandwiching the edges to be welded. , by inflating these two balloons, the outer periphery of the balloon and the inner periphery of the tube are sealed, and the space defined by these two balloons and the tube wall is sealed, and this space is filled with air. The edges of the two tubes to be welded are welded by sealing in active gas.

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

FIG. 1 is a diagram showing a method of welding a stainless steel tube body according to the present invention. In this figure, the symbols 3I, 32.3
Reference numeral 3 indicates a stainless steel tube body, and numeral 34 indicates a stainless steel tank in which the stainless steel tube body 34a is used. First, a method of welding the stainless steel tube body 31 and the stainless steel tube body 32 will be explained. Edge 31a of stainless steel tube 31 and edge 32 of stainless steel tube 32
a and temporarily secure it. Next, stainless steel tube 3
A double balloon 41 is inserted into the tube through the hole 31b provided in the tube. This double balloon 41 includes two balloons 41a,
41a are connected by a communication pipe 41b, and one balloon 4
A compressed air supply pipe 41c is connected to 1a. Such a double balloon 41, the two balloons 41
a, 41a is the edge 31a of the two tubes to be welded;
32i1 is placed on both sides. Then, the compressed air supply pipe 11c is connected to the compressed air supply pipe 42.
Connect to. Further, an argon gas supply pipe 13 is inserted through the hole 31b, and one end of the argon gas supply pipe 13 is connected to the two balloons 41a.
, 41a. Then, connect the end of the argon gas supply pipe 43 to the argon gas supply source 44.

In such a state, compressed air is first supplied from the compressed air supply source 42 to the two balloons 41a, 41a through the compressed space supply pipe 41C. And the above 2
The two balloons 41a, 41a are inflated, and the outer peripheral surfaces of the balloons are pressed against the inner peripheral parts of the stainless steel tube bodies 31, 32 to form a seal.

In this way, the space 1) defined by the two balloons 41a, 41a and the two tube bodies 31, 32 is sealed. Next, argon gas is supplied from the argon gas supply source 44 through the argon gas supply pipe 43 to fill the space. In this way, the edges 31a, 3 to be welded
The inside of the tube 2a becomes an inert gas atmosphere. In this state, the outer sides of the tube edges 31a and 32a are welded by inert gas arc welding or the like. After welding, the argon gas and compressed air are removed, and the double balloon 41 and argon gas supply pipe 13 are removed to complete the welding work.

By the same method as above, the stainless steel tube 32 and the stainless steel tube 33, and the stainless steel tube 33 and the stainless steel tube 34a of the stainless steel tank 34 are welded. Note that welding at these three locations may be performed simultaneously or sequentially and separately.

In this method of welding stainless steel tube bodies, the double balloon 4I is placed on both sides of the two 71 bodies, sandwiching the edges to be welded, and these two balloons are 4
1a is inflated and the outer periphery of the balloon 11a and the inner periphery of the tube are sealed, and the space (2) defined by these two balloons 41a, 41a and the tube wall is filled with argon gas. Since the edges of the two tubes to be welded are welded, argon gas only needs to be filled in the vicinity of the unwelded edges of the two tubes, which reduces the amount of argon gas used. In addition, the time required for filling with argon gas can be shortened. Particularly, as shown in FIG. 1, when the stainless steel tank 34 has a large volume, as shown in FIG. By using the double-barreled balloon 41, the amount of argon gas used can be reduced even in cases where there is no entrance such as a manhole to enter the gas, and the gas filling time is shortened. I can do it. Also, double balloon = 1
Since the welded portion can be sealed with a simple device such as No. 1, there is no need for a closing plate, an end plug, etc., and the cost of the work can be reduced.

In the above embodiment, argon gas is used as the inert gas, but there is no need to limit it to this, and other inert gases may be used.

"Effects of the Invention" As explained above, according to the present invention, two balloons are placed on both sides of the two tubes, sandwiching the edges to be welded, and these two balloons are inflated. 11) Seal the outer periphery of the balloon and the inner periphery of the tube, seal the space defined by the two balloons and the tube wall, and fill this space with an inert gas. Since the edges of the body to be welded are welded, inert gas only needs to be filled in the vicinity of the edges of the two tongue bodies to be welded, thus reducing the amount of inert gas used. In addition to being able to reduce the time required to fill with inert gas, it is also possible to sole the welded area with a simple device called a balloon, which reduces work costs. I can be hatched.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIGS. 2 to 4 are diagrams showing a conventional welding method for stainless steel tubes, and FIG. 2 is a welding method for welding two tubes. Figure 3 is a cross-sectional view showing the case where a tank with a manhole is connected to one pipe body, and Figure 1 is a cross-sectional view showing the case where a tank with a manhole etc. is connected to one pipe body. FIG. 3 is a cross-sectional view showing a case where they are connected. 31...Stainless steel pipe body, 31a end edge, 32...Stainless steel pipe body, 32a...
Edge, 33... Stainless steel tube body, 34a ・
... Stainless steel pipe body, 41a ... Balloon, D.
··space.

Claims (1)

[Claims] With the opening edges of two stainless steel tubes in contact with each other and the inside of the tubes filled with inert gas,
In a method for welding stainless steel tubes in which the edges of two tubes are welded, two balloons are placed on both sides of the two tubes across the edges to be welded, and these two balloons are inflated. The outer circumference of the balloon and the inner circumferential surface of the tube body are sealed, the space defined by the two balloons and the tube wall is sealed, and an inert gas is filled in this space to close the two tubes. A method for welding a stainless steel tube body, characterized in that the edges of the body to be welded are welded.