JPS60206565A - Welding method of welded flange inserted to pipe - Google Patents

Abstract

PURPOSE:To form a welded flange inserted to a pipe without posing problems occurring in residual stress and dust by interposing an annular elastic member between the top end of the pipe and the notched step of the flange. CONSTITUTION:A thin stainless steel sheet is worked to the annular elastic member 20 by press forming and the member 20 is fitted to the step wall 10 in the notched step of the flange 4. The pipe 2 is then inserted into the flange and the outside contact part between the pipe 2 and the flange 4 is welded. Even if the weld zone 12 shrinks after welding, the member 20 absorbs the shrinkage by slight deformation thus obviating generation of large residual stress in the weld zone 12. The member 20 closes a gap 14 to prevent stagnation of dust.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of welding a pipe socket weld flange, and more particularly to a welding method capable of closing the void inside the pipe.The present invention relates to a welding method for welding a pipe socket weld flange, and in particular to a welding method capable of closing a gap inside the pipe. Flange pipes are used. As shown in Fig. 1, the welding method for this socket weld flange involves inserting the pipe 2 into a circular notch step 6 previously provided in the flange 4 and welding the outer contact portions of the two.
If the tip 8 of the flange and the stepped wall 10 of the notch stepped portion 6 of the flange are in close contact, residual stress will occur in the welded portion 12 after welding.
Defects such as cracks are likely to occur, which may cause major accidents.

As a countermeasure against this, there is a conventional method, as shown in FIG. 2, in which the tip 8 of the pipe 2 and the 7-rank 40-step wall 10 are not brought into close contact with each other, but a gap 14 is maintained during welding, so that residual stress is not generated in the welded portion 12. However, with this method, dust 16 is present in the gap 14.
If flushing was performed after construction to ensure oil cleanliness, a small amount of dust 16 would enter the gap 14, prolonging the flushing time9, or dust 16 that had entered the gap 14 after operation. The disadvantage is that it can get mixed into the oil and cause failures in precision hydraulic equipment such as servo valves.

Another countermeasure is to perform internal welding 18 to close the gap 14 as shown in Fig. 3, but this method requires about twice the number of man-hours and is a big burden in terms of construction process and cost. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a simple welding method for pipe insertion welding flanges that does not cause problems due to residual stress and dust.

The gist of the present invention is as follows.

That is, in a pipe insertion welding flange welding method in which a pipe is inserted into a circular notch step ζ2 of a flange and the outer contact portion of the pipe and flange is welded, the tip of the pipe and the step of the flange notch step are welded. A method for welding a pipe insertion welding flange, which comprises the step of inserting the pipe into the notch step with a ring-shaped elastic member interposed between the pipe and the wall.

The details of the invention will be explained with reference to the illustrated embodiments.

First, as shown in FIG. 4, a thin stainless steel plate is press-formed into a shilling-shaped elastic member 20 (see FIG. 5,
As shown in FIG. 6, the elastic member 20 is fitted into the step wall 10 of the notch step of the flange 4, and then the pipe 2 is inserted.
and the external contact portion of the flange 4 are welded. In this embodiment, a ring-shaped elastic member 20 is interposed between the tip 8 of the pipe 2 and the step wall 10 of the notch step 6 of the seventh ridge 4 to close the gap 14 as shown in the figure. Oshi, welding part 2 after welding
Even if the elastic member 20 contracts, since the elastic member 20 has a shape as shown in FIGS. 4 and 6, it deforms slightly to absorb the contraction, and no large residual stress is generated in the welded portion 12. In this welding method, the elastic member 20 closes the gap 14 to prevent the accumulation of dust, there is no problem of residual stress, and the welding method can be carried out with the same construction load as the conventional welding method.

In the above embodiment, the ring-shaped elastic member 20 is pressed into the shape shown in FIG.
The member itself has elasticity.

A similar effect can be achieved in this case. That is, as shown in FIG. 7, an elastic member 2 having elastic resin ring fissures
Dust can be prevented and cracking due to residual stress can also be prevented by welding the 0A through the gap 14 between the tip 8 of the pipe 2 and the step wall 10 of the 7-zinge 4.

As is clear from the above-mentioned embodiments, the present invention has a ring-shaped elastic member interposed between the tip of the tube and the step wall of the step of the notch of the flange. By inserting the pipe and then welding the outer contact part of the pipe and flange, TL eliminates problems such as damage to the flange weld and failure of precision hydraulic equipment due to contamination by dust in the hydraulic piping with the same welding load as before. We were able to achieve the effect of eliminating the problem.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional socket welding method, FIGS. 2 and 3 are cross-sectional views showing a conventional improved socket welding method, and FIG. 4 is a cross-sectional view showing a conventional socket welding method. FIG. 5 is a perspective view showing a ring-shaped elastic member, FIG. 5 is a cross-sectional view showing the welding method of the present invention, FIG. 6 is a partially enlarged cross-sectional view showing the state of the elastic member in an embodiment of the present invention, and FIG. It is a sectional view showing other embodiments of an elastic member. 2...Pipe 4...Flange 6...Circular notch step 8...) Tip of pipe 10
... Step wall of notch step section 12 ... Welding section 20.2O
A...Elastic member agent Takeo Nakaji, patent attorney Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) In a pipe insertion welding flange welding method in which a pipe is inserted into a circular notch step of a flange and the outer contact portion of the pipe and flange is welded, the tip of the pipe and the step of the flange notch are welded. A method for welding a pipe insertion welding flange, comprising the step of inserting the pipe into a notch step with a ring-shaped elastic member interposed between the pipe and the wall.