JPH106016A - Pipe welding method and joining structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To make a metal pipe and a plate material or pipes airtightly connectable only by electric resistance welding. SOLUTION: A rounded bulging portion is formed on the joining end side of a pipe 1 to be joined to a base material, and then a joining end of the pipe 1 is formed in a mounting hole formed in the base material and having a slightly larger diameter than the pipe 1. And the base material and the pipe 1 are lowered by a welding machine and the upper electrode is lowered by a cylinder.
By applying a high current of 000 to 15,000 amperes for a very short time several times, it is possible to concentrate on at least the hole edge portion of the mounting hole in the base material and the seating portion of the flange portion of the pipe 1 with respect to the hole edge portion. By applying a high current to
SU with relatively large electric resistance and not suitable for electric resistance welding
Even if the material is S, it is melted and fused stepwise, and the bulging portion is deformed to form a flange portion. That is, the nugget has a predetermined strength and the welding cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe welding method for joining a pipe and a plate or pipes by electric resistance welding, and a joining structure thereof.

[0002]

2. Description of the Related Art Conventionally, brazing is the main method for joining pipes and plates or pipes that require airtightness to be used as a flow path of cooling water for a water-cooled engine. In this case, vacuum brazing is often used, and in such a method, (1) temporarily fixing parts, (2) cleaning, (3) drying, (4) applying brazing material to the joint (5) Put in a batch-type vacuum furnace
Heat treatment was carried out for 2 to 2 hours. (6) Inspection process was carried out, but washing water entered into the pipe during the washing process of (2). And since the brazing material application process of (4) is manual,
It has the disadvantage of requiring a long time for pretreatment, and the application process of the brazing material in (4) requires manual skill, and the joint surface of the finished product solidifies with the applied brazing material dripping. In addition, since the joining members are connected and fixed integrally with the brazing material, the joining strength is weak due to the strength of the solidified brazing material itself, and the joint is weak. Was.

[0003] In a batch type vacuum furnace, the occupied space including peripheral equipment is very large, and a plurality of units cannot be installed in a limited site, and the members to be welded are neatly arranged in a metal basket. It had to be housed in the furnace side by side so as not to contact, which was extremely troublesome.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for welding a pipe made of a metal, especially a SUS material, by simplifying the welding process and reducing the welding cost by only being able to join by electric resistance welding. And a joint structure thereof.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a vacuum brazing method based on the above-mentioned prior art, which is performed as welding that requires airtightness between a pipe and a plate or between pipes. In view of the need for a process and a brazing material application step, which is extremely troublesome, a rounded bulge is formed on the joint end side of the pipe to be joined to the base material, and then formed on the base material.
By fitting the joint end of the pipe into a mounting hole slightly larger in diameter than the pipe, the bulged portion of the pipe is seated and in contact with the hole edge of the mounting hole in the base material, enabling ring projection welding. Then, the base material and the pipe in the temporarily fixed state are set between the upper and lower electrodes in the welding machine, and the upper electrode is lowered between the upper and lower electrodes by a cylinder.
By applying a high current of 2000 to 15000 amps for a very short time 3 to 4 times within a short time, only the hole edge of the mounting hole in the base material and the seating portion with respect to the hole edge of the flange in the pipe are provided. By passing a high current several times in a very short cycle in a concentrated manner, even if the SUS material has a relatively large electric resistance and is not suitable for electric resistance welding,
It allows for fusion.

[0006] In addition, the base material and the pipe are formed by forming a nugget extending at least over the hole edge of the mounting hole in the base material and the seating portion of the flange portion of the pipe with respect to the hole edge. While welding in an airtight manner and deforming the bulging part to form a flange, the fusion part of the molten state of the base material and the pipe caused by the current supply for one cycle (1/60 second) is compressed. In order to solve the above problem, the welded portion, that is, the nugget, in which the hole edge portion of the mounting hole in the base material and the seating portion of the flange portion of the pipe with respect to the hole edge portion are fused and solidified, that is, the nugget has predetermined strength. It was something we did not solve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1, 2, and 3, a pipe 1 joined to a base material A is made of metal, particularly SUS material. The pipe 1 is buckled in an outwardly bulging shape near the joint end side of the intermediate portion to form a flange 2, and the outer diameter of the flange 2 is
It is desirable to make the outer diameter about 30% larger than the outer diameter.

A base material A shown in FIG. 1 is a plate material 3, and a joint end side of the pipe 1 is fitted to a hole edge 5 of a mounting hole 4 formed on the plate material 3 and having a larger diameter than the pipe 1. And at least a hole edge 5 of the mounting hole 4 and the pipe 1 with respect to the hole edge 5.
A nugget 6 which is a material fusion portion of the pipe 1 and the plate member 3 is formed so as to straddle the seating portion of the flange portion 2 in FIG.

The base material A shown in FIG.
The pipe 7 has a diameter slightly larger than the outer diameter of the pipe 7, and the pipe 1
Of the pipe 7 so as to straddle at least the hole edge 9 of the mounting hole 8 of the large-diameter pipe 7 and the seating portion of the flange 2 of the pipe 1 with respect to the hole edge 9. 1 and a nugget 10 which is a material fusion portion of the large diameter pipe 7.

A base material A shown in FIG. 3 is a pipe 11 having a diameter larger than that of the pipe 1. A flat surface 12 formed by pressing the side surface of the pipe 11 has a mounting hole having a diameter slightly larger than the outer diameter of the pipe 1. At the same time, the joining end side of the pipe 1 is fitted into the mounting hole 13, and straddles at least the hole edge 14 of the mounting hole 13 and the seating portion of the flange 2 of the pipe 1 with respect to the hole edge 14. Like
Nugget which is a material fusion part of pipe 1 and large diameter pipe 11
Forming 15.

The nuggets 6, 10, and 15 have mounting holes.
13 and the base material A and the pipe 1 are expanded outward from the seated portion of the flange 2 of the pipe 1 with respect to the hole edge 14.
It is desirable to cover a wide range, such as straddling the mutual contact portion of the flange portion 2 in the above.

Next, a method of welding the pipe 1 will be described. First, as a pretreatment, a rounded outward bulging portion 16 is formed on the joining end side of the pipe 1 on the side joined to the base material A. Then, the joint end of the pipe 1 is fitted into the attachment hole 4 of the plate 3 and the attachment end 13 of the large-diameter pipe 7 or the attachment hole 13 on the side surface of the pipe 11, so that the upper and lower electrodes E and Ea of the welding machine W are connected. , Pipe 1 to lower electrode Ea, plate material 3, which is base material A, pipe 7,
11 are installed so as to be in contact with the upper electrode E, respectively.

When the upper electrode E is lowered by the cylinder C and current is applied to the upper and lower electrodes E and Ea while pressing the base material A toward the pipe 1, specifically, 120
A high current of 00 to 15000 amps is applied for an extremely short time, specifically, for 1 to 3 cycles (1 cycle = 1/60 second), and the edge of the mounting holes 4, 8, and 13 in the base material A. 5,
9 and 14 and the seating portion of the bulging portion 16 of the pipe 1 with respect to the hole edge portions 5, 9 and 14 are fused and fused.
By repeating 3-4 times between 10 and 10 cycles,
The bulging portion 16 is further buckled and deformed to form the flange portion 2, and the fused portion gradually expands so that at least the hole edge portion 5 in the base material A,
9 and 14, and hole edges 5, 9, and 14 of the flange 2 in the pipe 1
The nuggets 6, 10, and 15 are formed over the entire circumference so as to straddle the seating portion, and the base material A and the pipe 1 are welded to form a highly airtight welded portion.

The nuggets 6, 10, and 15 are provided with holes 5, 9, and 14 of the mounting holes 4, 8, and 13 in the base material A, respectively.
In addition to the seating portion of the bulging portion 16 of the pipe 1 with respect to the pipes 9 and 14, the outer peripheral portion of the hole edge portions 5, 9, and 14 in the base material A and the contact portion of the flange portion 2 with the base material A are straddled. It is desirable to form it.

If the pressing force of the upper electrode E is small during energization or melting, the bonding strength is weakened. Conversely, if the pressing force is large, the material itself is crushed and the contact area becomes large, so that a higher current needs to be applied. Therefore, the upper electrode E is instantaneously lowered following an extremely short energization cycle, a predetermined pressing force is applied to the molten portion, and the solidified weld portion, that is, the nuggets 6, 10,.
The cylinder C is controlled so that 15 has a predetermined strength.

The energization time and the number of energizations vary depending on conditions such as the base material A and the material and thickness of the pipe.
As shown in FIG. 6, one cycle of energization is performed for three cycles during six cycles.
If it is repeated several times, it can be welded in a completely airtight state.

Therefore, the method for welding pipes according to the present invention is suitable for manufacturing by flowing one by one in the order of pre-process, welding and post-process, and is most suitable for manufacturing small lot products.

[0018]

According to the present invention, the pipe 1 to be joined to the base material A is formed with a rounded bulging portion 16 on the joint end side, and then the mounting holes 4, 8, 13 formed in the base material A are formed. The upper and lower electrodes E, E, in the welding machine W are fitted with the joint ends of the pipes 1 so that the bulging portions 16 of the pipes 1 are seated in the hole edges 5, 9, 14 of the mounting holes 4, 8, 13. The base material A was set between Ea
And pipe 1 can be brought into a state in which ring projection welding can be performed, and a high current is applied between upper and lower electrodes E and Ea several times within a very short time while lowering upper electrode E by cylinder C. In addition, since the cylinder C is controlled so that the upper electrode E instantaneously descends in accordance with the energization cycle, the melting and the fusion part by energization can be compressed with an appropriate pressing force before solidification. , That is, the strength of the nuggets 6, 10, and 15 can be improved.

Further, the bulging portion 16 is formed by the pressing force of the cylinder C.
Is deformed to form the flange portion 2, so that the nuggets 6, 10, 15 described later are formed with the hole edges 5, 9, 14 of the mounting holes 4, 8, 13 in the base material A and the hole edge portions. Not only the seating portion of the flange portion 2 (bulging portion 16) with respect to 5, 9, 14 but also the outer peripheral portion of the hole edge portion 5, 9, 14 in the base material A and the contact portion of the flange portion 2 with the base material A. Therefore, the welding strength can be improved.

Further, the hole edges 5, 9, 14 of the mounting holes 4, 8, 13 in the base material A and the flange 2 with respect to the hole edges 5, 9, 14
Nuggets 6, 10, and 15 are melted and fused all around.
Since the base material A and the pipe 1 are welded so as to form, the flow path is completely sealed by the nuggets 6, 10, and 15, so that highly airtight welding can be performed.

A flange 2 is attached to the joining end of the metal pipe 1.
Is buckled to fit a joint end of the pipe 1 into a mounting hole 4 formed in a plate material 3 which is a metal base material A, and a hole edge 5 of the mounting hole 4 and the hole edge 5 are formed. The nugget 6 in which the seating portion of the flange portion 2 of the pipe 1 in the pipe 1 is melted and fused is formed over the entire circumference, The nugget 10 in which the hole edge 9 of the large diameter pipe 7 and the seating portion of the flange 2 of the pipe 1 with respect to the hole edge 9 are fused and fused together.
Or a mounting hole 13 is formed in a flat surface 12 formed on a side surface of a large-diameter pipe 11 which is a metal base material A, and the joining end side of the pipe 1 is formed in the mounting hole 13. At the same time, the nugget 15 formed by melting and fusing the hole edge 14 of the mounting hole 13 and the seating portion of the flange 2 of the pipe 1 with respect to the hole edge 14 was formed. The airtightness of the flow path on the base material A side (the plate material 3 or the large-diameter pipes 7 and 11) can be ensured, and the pipe 1 and the base material A (the plate material 3) can be secured.
Alternatively, the practical effect is extremely large, for example, the large-diameter pipes 7 and 11) can be firmly integrated.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing a joint structure between a pipe and a plate material.

FIG. 2 is an enlarged sectional view of a main part showing a series joining structure of pipes.

FIG. 3 is an enlarged sectional view of a main part showing a joining structure of a small-diameter pipe to a large-diameter pipe side surface.

FIG. 4 is an enlarged view of a main part of FIG. 1, 2 or 3.

FIG. 5 is a partial cross-sectional side view showing a welding process.

FIG. 6 is a graph showing a change in the amount of current with the passage of current during welding.

FIG. 7 is a schematic side view of a welding machine.

[Explanation of symbols]

 Reference Signs List 1 pipe 2 flange 3 plate 4 mounting hole 5 hole edge 6 nugget 7 large-diameter pipe 8 mounting hole 9 hole edge 10 nugget 11 large-diameter pipe 12 flat surface 13 mounting hole 14 hole edge 15 nugget 16 bulge Part A Base material

Claims (4)

[Claims] 1. A rounded bulging portion is formed on the joining end side of a pipe to be joined to a base material, and then the connecting end of the pipe is attached to a mounting hole formed in the base material, and the bulging portion of the pipe is attached. Fitted so as to be seated on the edge of the hole, placed between the upper and lower electrodes in the welding machine, while lowering the upper electrode by the cylinder,
A high current is applied between the upper and lower electrodes several times within a very short time, and the cylinder is controlled so that the upper electrode drops instantly following the current application cycle. The base material is deformed to form a flange, and the seating portion of the mounting hole in the base material with respect to the hole edge of the mounting hole and the flange of the pipe is melted and fused all around to form a nugget. A pipe welding method, characterized in that the pipe and the pipe are welded. 2. A buckling portion is formed on a joining end side of a metal pipe to buckle the fitting end of the pipe into a mounting hole formed in a plate material which is a metal base material. A joint structure for a pipe, wherein a nugget in which a hole edge portion and a seat portion of a flange portion of the pipe with respect to the hole edge portion are melted and fused is formed all around. 3. A buckling portion is formed on the joining end side of the metal pipe, and the joining end of the pipe is fitted to the joining end side of the large-diameter pipe which is a metal base material. A joint structure for pipes, wherein a nugget in which a hole edge of a simple pipe and a seating portion of a flange portion of the pipe with respect to the hole edge are fused and fused is formed all around. 4. A buckling portion is formed on a joining end side of a metal pipe, a mounting hole is formed in a flat surface formed on a side surface of a large-diameter pipe as a metal base material, and the mounting hole is formed in the mounting hole. A pipe characterized in that a joining end of a pipe is fitted, and a hole nugget of the mounting hole and a seating portion of a flange portion of the pipe with respect to the hole edge are fused and fused to form a nugget all around. Joint structure.