JPH1163329A - How to attach the pipe connection flange - Google Patents

Abstract

(57) [Summary] [Problem] In mounting a connecting flange to a pipe, the temporary welding is eliminated, and the flange is welded accurately, stably and automatically by an automatic welding machine, and the flange mounting time is reduced. To prevent a decrease in the operating rate of automatic welding of the automatic welding machine due to tacking. SOLUTION: After inserting a cored bar 2 having a conical surface on the outer periphery into an end of a tube 1, the tube 1 is pressed to expand the end,
Next, after the core metal 2 is removed from the expanded end 4, a flange 6 is fitted from the side opposite to the expanded end 4 with a plate 5 interposed between the end surface of the expanded end 4 and the platen 3. Then, the flange 6 is pressed into the expanded end 4 of the pipe 1 by a press to reduce the diameter of the expanded end 4. Thereafter, the plate 5 is removed from the end face of the pipe 1, and the pipe 1 and the flange are removed. 6 is welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for attaching a connecting flange to an outer periphery of an end of a pipe.

[0002]

2. Description of the Related Art In recent years, in order to attach a connecting flange to the outer periphery of an end of a pipe, automatic welding using an automatic welding machine has become popular. By the way, in the automatic welding machine, the temporary welding before performing the actual welding must be performed by a different size and method from the temporary welding by the manual welding. That is, as shown in comparison with FIGS. 2 and 3, temporary attachment in the case of automatic welding and manual welding by an automatic welding machine includes (1) a difference in the mounting position of the flange F with respect to the pipe P, and (2) a pipe P. And (3) the size of the tack w. In the case of automatic welding, the difference in (1) is to prevent the weld bead from covering the sheet surface, the difference in (2) is to prevent the weld bead from becoming uneven, and the difference in (3) The difference is to stabilize the welding.

[0003] However, in the case of automatic welding by an automatic welding machine, if the mounting position of the flange F with respect to the pipe P is improper, a welding bead B is applied to the surface of the flange F as shown in FIG. If the gap C between the pipe P and the flange F is improper, the welded portion W where there is no gap C becomes convex as shown in FIG. 5, and the weld metal flows through the portion where the gap C is large, The weld W 'becomes concave. Further, if the size of the temporary attachment w at the four circumferential positions is inappropriate, when the temporary attachment w is small as shown in FIG. 6A, the temporary attachment w hits the welding wire L, and as shown in FIG. As shown in (b), when the temporary attachment w is large, the electrode E hits the temporary attachment w.

[0004] Then, as a problem of the tacking work for automatic welding by the automatic welding machine, since the length of the pipe P is different, it is necessary to sort from a cutting instruction to automatic welding.
In addition, due to the size of the gap C and the size of the tacking w, the tacking work procedure changes and the working time is lengthened. Further, it is difficult to cope with welding of high quality requirements due to certification and the like. The operating rate of automatic welding of the welding machine is decreasing.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention eliminates temporary attachment and prevents the flange from being attached to the pipe in order to prevent a reduction in the operating rate of automatic welding of the automatic welding machine due to the temporary attachment of the flange to the pipe. An object of the present invention is to provide a method for mounting a pipe connecting flange, which can perform welding accurately and stably automatically and can reduce a mounting time of the flange.

[0006]

According to the present invention, there is provided a method for mounting a connecting flange of a pipe according to the present invention, comprising the steps of: inserting a metal core having a conical surface on an outer periphery into an end of the pipe; Press to expand the end, then remove the core metal from the expanded end, then place the plate between the end face of the expanded end and the platen on the opposite side of the expanded end to the pipe And then press-fit the flange to the expanded end of the pipe with a press to reduce the expanded end, then remove the plate from the end face of the pipe and weld the pipe and flange It is characterized by doing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for mounting a pipe connecting flange according to the present invention will be described with reference to the drawings. The inner diameter is 151.0 mm and the outer diameter is 162.5 m shown in FIG.
m, in the end of a steel tube 1 250 mm long, FIG.
After inserting the core 2 in the shape of a truncated cone having a 10-degree taper as shown in FIG.
The end was expanded as shown in FIG. Next, a truncated cone-shaped cored bar 2 is removed from the expanded end 4, and the steel pipe 1 is slightly smaller than the outer diameter of the steel pipe 1 disposed on the end face of the expanded end 4 as shown in FIG. It was installed vertically on the platen 3 via a plate 5 having a small diameter and a diameter larger than the inner diameter of the steel pipe 1.
Next, as shown in FIG. 1E, the inner diameter is 166.6 mm, the outer diameter is 280 mm, and the thickness is 22 from the other end (upper end) of the steel pipe 1.
A ring-shaped flange 6 made of stainless steel for connection is fitted, and the flange 6 is pressed onto the expanded end 4 by a press as shown in FIG. Reduced diameter. Thereafter, the plate 5 is removed from the lower end surface of the steel pipe 1, and as shown in FIG. 1 (g), the lower end surface of the steel pipe 1, the inner peripheral surface of the flange 6, the outer peripheral surface of the steel pipe 1, and the outer peripheral surface of the flange 6 are formed. , And a flange 6 was attached to the outer periphery of the end of the steel pipe 1. The final welding 7 was performed by an automatic welding machine.

When the connection flange 6 is attached to the end of the steel pipe 1 as described above, the end is expanded, the flange 6 is press-fitted to the expanded end 4 by a press, and the expanded end 4 is contracted. Because of the diameter, there is no gap between the inner peripheral surface of the flange 6 and the outer peripheral surface of the end of the steel pipe 1, and the flange 6 is accurately and stably positioned and fixed. Temporary attachment is no longer necessary. Further, in this state, since the lower end face of the steel pipe 1 and the flange 6 were automatically welded by an automatic welding machine, the flange 6 was not tilted or misaligned at all, and the flange 6 with high dimensional accuracy could be attached.

In the above-described embodiment, the connection flange 6 is attached to the outer periphery of the end of the pipe 1. The pipe 1 is placed vertically, and the flange 6 is pressed onto the expanded end 4 from above, and the expanded end is formed. After the diameter of the portion 4 is reduced, welding is performed, but the pipe 1 is placed in a horizontal state, and the flange 6 is pressed against the expanded end 4 from the side,
The expanded end 4 may be reduced in diameter and then welded.

[0010]

As can be seen from the above description, the method of mounting the pipe connecting flange according to the present invention expands the end of the pipe, press-fits the flange to the expanded end, and reduces the diameter of the expanded end. Therefore, there is no gap, the positioning is fixed stably with high accuracy, no temporary attachment is required, and the welding of the flange to the pipe is automatically performed by an automatic welding machine, so that no inclination or misalignment of the flange occurs. In addition to the fact that a flange with high dimensional accuracy can be mounted, the flange mounting time is shortened, and the operation rate of automatic welding of the automatic welding machine is improved.

[Brief description of the drawings]

FIG. 1 shows a method of mounting a pipe connecting flange according to the present invention, wherein (a) to (g) are process diagrams.

FIG. 2 is an explanatory view of a method of attaching a connection flange to a pipe by automatic welding by a conventional automatic welding machine.

FIG. 3 is an explanatory view of a conventional method of attaching a connection flange to a pipe by manual welding.

FIG. 4 is a view showing a state of a weld bead due to an improper flange mounting position in the case of automatic welding by a conventional automatic welding machine.

FIG. 5 is a view showing a state of a welded portion due to improper clearance between a pipe and a flange in a case of automatic welding by a conventional automatic welding machine.

6A and 6B show the state of the electrode and the welding wire due to improper size of the temporary attachment in the case of automatic welding by a conventional automatic welding machine, wherein FIG. It's time for a big attachment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel pipe 2 Core metal 3 Surface plate 4 Expansion end 5 Plate 6 Flange 7 Welding

Claims (1)

[Claims] 1. After inserting a metal core having a conical surface on the outer circumference into the end of the pipe, pressing the pipe to expand the end, then removing the core from the expansion end, and then expanding the pipe With a plate interposed between the end face of the part and the surface plate, a flange is fitted to the pipe from the side opposite to the expanded end, and then the flange is pressed into the expanded end of the pipe by a press. A method for mounting a pipe connecting flange, comprising reducing the diameter of an expanded pipe end, removing the plate from the end face of the pipe, and then welding the pipe and the flange.