JPS59101282A - Plug welding method - Google Patents

Abstract

PURPOSE:To seal satisfactorily an ultrafine tube and to improve the quality in a sealed part by driving a plug material which is the same or approximately the same as the material of a tube plate into said tube and subjecting the plug material and the tube plate to low-frequency pulse TIG welding. CONSTITUTION:A plug 14 is driven into an ultrafine tube 13 inserted into the hole 12 of a tube plate 11 and is subjected to low-frequency pulse TIG welding. If the plate 11 is formed of, for example, pure nickel, the plug 14 is formed of pure nickel or the like which is the same or approximately the same as said material. The tube 13 is a palladium tube. The small plug 14 is melted and further the plate 11 is melted according to the above-mentioned method and therefore the welding is easily made possible without adding a welding wire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plug welding method for sealing ultrafine tubes.

When sealing a thin tube using the conventional plug welding method, a tube 3 inserted into a tube hole 2 of a tube plate 1 as shown in FIGS.
Drive plug 4 into tube plate 1. The tube 3 and plug 4 were seal welded. In the figure, 5 indicates a welded part.

However, in this method, the tube 3 is extremely fine (for example, outer diameter 1.6 mmφ, wall thickness 0.075 amφ) and the size of the tube hole 2 is narrow (for example, 1.0 to 2.2 mm). tm
), and when the material is palladium, there are the following disadvantages. In other words, when welding with a constant current, it is difficult to adjust the bead size and penetration depth. Also, if the current is too high, the forging becomes too large and there is a risk of damaging adjacent pipe holes, and if the current is too low, poor fusion will occur. Furthermore, palladium has the property of permeating hydrogen gas and is susceptible to welding defects such as blowholes.

The present invention has been made in view of the above circumstances, and its purpose is to provide a plug welding method that can effectively seal an ultrafine tube and improve the quality of the sealed portion. be.

That is, the present invention provides a plug welding method for sealing a tube sheet and an ultra-fine tube using a plug material, in which a plug material made of the same material or approximately the same material as the tube sheet is driven into the ultra-fine tube, and the plug material and the tube sheet are bonded together at a low temperature. It is characterized by frequency pulse TIG welding.

The present invention will be described below based on illustrated embodiments.

The present invention provides ultrafine tubes 13 inserted into tube holes 12 of a tube plate 11.
To! The lug 14 is driven in and low frequency pulse TIG welding is performed. If the tube sheet 11 is made of pure nickel, the plug 14 is also made of pure nickel or the like, which is the same material or substantially the same material. Also, is the ultrafine tube 13 NoJ? It's a radium tube. Also, for low frequency pulse TIG welding, it is approximately 0.1
sec ~0.2 sec, preferably 0.15 sec
Let it be a low frequency of c.

According to this method, the small plug 14 is melted and the tube sheet 1 is melted well, so welding can be easily performed without adding welding wire.

Further, by driving the plug 14, the ultrafine tube 13 is compressed and becomes thinner, so that the influence of the amount of melting of the ultrafine tube 13 can be reduced. Furthermore, since the gap between the ultrafine tube 13 and the tube sheet 11 or the plug 14 is reduced, and the tube sheet 11 and the plug 14 are made of the same material or substantially the same material, the occurrence of defects due to welding is reduced.

Moreover, since low-frequency pulse TIG welding is used, even if the dimension d between the pipe holes is narrow (for example, 1.0 to 2.2 m+)
An appropriate shape of the welded portion 15 and the shape of the melt penetration can be obtained without damaging the adjacent pipe hole 12. That is, the high pulses melt and the low pulses provide a cooling effect, but by making the intervals longer as the pulses are low, it is possible to adjust the size and shape of the bead and the depth of melt penetration.

As described above, according to the present invention, the material of the plug is made of a material that easily fuses with the pipe and tube sheet to prevent defects in the welded part, and the low-frequency pulsed TIG method is adopted as the welding method to weld adjacent holes. Appropriate bead shape and melt penetration shape can be obtained without damage.

Therefore, it is extremely effective for repairing, for example, the i4 radium capillary tube and tube plate joint of the hydrogen separator 1.

[Brief explanation of the drawing]

Figures 1 to 3 show the conventional plug welding method. Figure 1 is a plan view of the tube sheet, thin tube, and plug before welding, Figure 2 is a plan view after welding, and Figure 3- 2 is a cross-sectional view taken along line G in FIG. 2, FIGS. 4 to 6 show an example of the plug welding method of the present invention, and FIG. 5 is a sectional view after welding, and FIG. 6 is a plan view. DESCRIPTION OF SYMBOLS 11... Tube sheet, 12... Tube hole, 13... Ultrafine tube, 14... Plug, J5-... Welding part.

Claims (1)

[Claims] Plug welding method in which the tube sheet and the ultrafine tube are sealed using a plug material (Second step, a plug material made of the same material or approximately the same material as the tube sheet is driven into the ultrafine tube, and the plug material and the tube sheet are welded using a low frequency pulse. A plug welding method characterized by TIG welding.