JP2000153377A - Friction welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a tool from deformation due to a load by welding while supporting a load due to a metal bar through a support means attachably/ detachably arranged to the rear side face of the welding part of an object to be worked. SOLUTION: In the friction welding, e.g. a load of 1000 kg is applied to a metal bar 1 during welding in the downward direction. For this purpose, a load support mechanism 6 is arranged in the cylindrical tube 3. The support mechanism 6 is adjustable to an arbitrary length in a sliding type by hydraulic force 7, further is moved on a rail 8 arranged at a side opposite to the welding part 5 of the cylindrical tube 3 in the tangential direction. Accordingly, in the case of a long cylindrical tube 3, the rear side face of the welding part 5 is locally and stably supported. By this method, the tip part of the support mechanism 6 is brought into tight contact with the rear side face of the welding part 5, the downward load of the metal bar 1 is effectively received, welding is done with reducing deformation and buckling of the cylindrical tube 3 and without causing breakage of the metal tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a friction welding method,
In particular, the present invention relates to a welding method that reduces deformation and welding defects due to welding and contributes to improving the quality of a weld.

[0002]

2. Description of the Related Art In a friction welding method, a metal rod of a material substantially harder than a material of a workpiece is inserted into a welded portion of the workpiece, and the metal rod is moved while rotating or the workpiece itself is moved. In this case, the welding is performed by frictional heat generated between the metal bar and the workpiece. This is known from Japanese Patent Publication No. 7-505090 (EPO615480B1).
That is, the method utilizes a plastic flow phenomenon caused by frictional heat between a metal rod and a workpiece, and does not melt and weld a workpiece as in arc welding. Furthermore, this friction welding method is different from the conventional friction welding method in which the workpieces are rotated and the welding method using the frictional heat is performed, and the workpiece is continuously welded in the longitudinal direction of the welding line, that is, in the longitudinal direction. There is a feature that can be welded.

[0003]

[Problems to be Solved by the Invention] The above-mentioned special publication 7-50509
In the friction welding method disclosed in Japanese Patent Publication No. 0, welding is performed by frictional heat generated between the metal rod and the workpiece. When a workpiece is welded by the present welding method, the following problems occur.

(1) When the welding length of the workpiece is short, or when the workpiece is thin or has good workability, the frictional heat is relatively small and the welding deformation is small. Further, the occurrence of welding defects is small. However, when the weld length of the workpiece is long or thick, or when the workpiece has high rigidity and poor weldability, the frictional heat is large and the welding deformation is large. Further, welding defects are also likely to occur. In addition, since the temperature of the metal bar increases, breakage frequently occurs.

(2) In the friction welding method, a large load is applied to the metal rod in a downward direction. For this reason, when the inner surface of a cylindrical tube or the like is welded to a hollow or other workpiece, the cylindrical tube is deformed or buckled by a downward load caused by a metal rod.

(3) When the circumferential direction of the cylindrical pipe is welded by the main welding, when the position of the metal rod is located at the center or the front of the cylindrical pipe with respect to the rotation direction of the cylindrical pipe, the metal rod and the workpiece are disposed. Since a gap is formed between the surface and the surface, welding defects are likely to occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a friction welding method capable of performing welding without being deformed by a load of a tool and having a small welding deformation.

[0008]

According to the present invention, a metal rod made of a material harder than the material of a workpiece is inserted into a weld of the workpiece,
In the friction welding method of welding by plastic flow generated in the workpiece by moving the metal rod while rotating, in the friction welding method, the support is provided detachably on the back surface of the welded portion of the workpiece. In the friction welding method, the welding is performed while supporting a load by a metal rod. The present invention is characterized in that the welding is performed in a coolant as a forced cooling supported by the above-mentioned supporting means and the welding is performed while jetting water or an inert gas to the welded portion.

Further, the present invention provides a method of inserting a metal rod of a material harder than a cylindrical pipe of a workpiece into a welded portion of the workpiece, and moving or moving the workpiece while rotating the metal rod. Due to the plastic flow generated in the workpiece,
In the friction welding method for a cylindrical pipe for welding the cylindrical pipe in a longitudinal direction or a circumferential direction, the load by the metal rod is supported by support means detachably provided on a back surface of the welded portion of the workpiece. The present invention is the friction welding method for a cylindrical pipe, wherein the welding is performed while forcibly cooling an inner peripheral surface or an outer peripheral surface of the cylindrical pipe.

According to the present invention, a means for reducing welding deformation and welding defects due to frictional heat generated between a metal rod and a workpiece is to perform welding while forcibly cooling the workpiece during welding. In particular, it can be achieved by pouring a coolant around the metal rod and around the weld or by welding in the coolant. Further, it can be achieved by friction welding the conductor provided with the cooling mechanism so as to surround a part or the entire surface of the workpiece.

Further, according to the present invention, a supporting mechanism capable of arbitrarily adjusting the length of an inner surface of a cylindrical tube is provided for preventing deformation or buckling of the cylindrical tube due to a downward load of a metal rod in friction welding of the cylindrical tube. Can be prevented.

According to the present invention, a welding defect caused by a gap between a metal rod and a surface of a workpiece when welding a cylindrical pipe in a circumferential direction is caused by changing the position of the metal rod with respect to the rotation direction of the cylindrical pipe. Can be prevented by arranging them behind the center.

According to the present invention, the frictional heat generated between the metal rod and the workpiece can be efficiently cooled by forcibly cooling the periphery of the metal rod and the weld with a coolant. This cooling can reduce the deformation of the workpiece after welding and the occurrence of welding defects due to the deformation. Further, since the metal rod can be efficiently cooled, the temperature can be extremely reduced. Therefore, breakage of the metal rod can be prevented even during continuous long-time welding. Further, the temperature of the workpiece can be efficiently cooled even when the workpiece is surrounded by a conductor having a cooling structure and welded.

On the other hand, according to the present invention, by arranging a support mechanism whose length can be adjusted arbitrarily on the inner surface of the cylindrical tube, a downward load by the metal rod can be efficiently received from the inner surface side between the cylinders. . For this reason, deformation and buckling of the cylindrical tube can be prevented.

Further, in the present invention, when friction welding is performed in the circumferential direction of a cylindrical tube, the position of the metal rod is arranged rearward of the center of the cylindrical tube with respect to the rotation direction of the cylindrical tube, so that the metal rod can be processed. Adhesion with the object surface can be improved. This allows
Welding defects can be prevented.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 shows a friction welding of a cylindrical pipe used for a gas interrupter for electric power transportation, in which a cylindrical pipe 3 is welded while cooling water 2 is applied around a metal rod 1 according to the present invention. The perspective view which carries out friction welding of the groove part 4 in the longitudinal direction is shown. The cylindrical tube 3 is made of an aluminum alloy having an outer diameter of 1000 mm, an inner diameter of 980 mm, and a length of 5000 mm (JIS standard A508).
3). FIG. 2 shows a cross section of the welded portion in FIG.
The tip of the metal rod 1 is thinned and the tip diameter is 8mm
Is a diameter of a thick portion of 20 mm. This narrow portion is inserted into the butt weld and moves in the direction of the welding line while rotating.

In this embodiment, the temperature of the cooling water is 1
At 0 ° C, the flow rate is 2ι / min. The rotation speed of the metal rod is 10
00 rpm, the moving speed is 300 mm / min. By the cooling, the temperature in the vicinity of the weld and the temperature of the metal rod are set to 100 ° C.
You can: Thereby, welding deformation can be reduced to １ ／ or less as compared with the conventional welding method without cooling. In addition, metal rod 1
Is cooled efficiently, so that the temperature rise is small and welding can be performed for a long time without damage.

On the other hand, in the present friction welding, a load of about 1000 kg is applied downward by the metal rod 1 during welding. For this reason, a load support mechanism 6 for supporting a load is disposed inside the cylindrical tube. The load supporting mechanism 6 can be slidably adjusted to an arbitrary length by an oil pressure 7. Further, the support mechanism 6 can move in a welding line direction on a rail 8 provided in a direction opposite to a welding portion of the cylindrical pipe. Therefore, even in the case of a long cylindrical tube, the back surface of the welded portion can be locally and stably supported.

By the above means, the tip of the support mechanism 6 can be efficiently brought into close contact with the back side of the welded portion 5. Thus, the downward load of the metal rod 1 can be efficiently received, so that the cylindrical tube can be welded with less deformation and buckling. Furthermore, welding can be performed without breaking the metal rod.

(Embodiment 2) FIG. 3 shows a cylindrical pipe 3 used in a gas circuit breaker for electric power, in which a cylindrical pipe 3 is circumferentially welded while cooling water 2 is applied around a metal rod 1. The perspective view which carries out friction welding of the groove part 4 is shown. The cylindrical tube 3 is an aluminum alloy (JIS standard A5052) having an outer diameter of 1000 mm, an inner diameter of 980 mm, and a length of 4000 mm. FIG. 4 shows FIG.
2 shows a cross section of a welded portion in FIG. The tip of the metal rod 1 is thinned, the diameter of the tip is 10 mm, and the diameter of the thick part is 20
mm. After inserting the narrow portion into the butt weld, the cylindrical tube is rotated. Thereby, the welded portion 5 is formed.

In this embodiment, the position of the metal rod 1 with respect to the rotation direction of the cylindrical tube 3 is arranged at a position 30 mm rearward from the center 10 of the cylindrical tube 3 with respect to the rotation direction 9 of the cylindrical tube 3.

In this embodiment, the flow rate of the cooling water is 2
The rotation speed of the metal rod is 1000 rpm, and the rotational speed of the workpiece is 200 mm / min.

5 mm from the weld of the cylindrical pipe by the cooling
The remote surface temperature is below 100 ° C. For this reason, the deformation after welding can be reduced to half compared with the conventional weld without cooling. Furthermore, since the metal rod 1 is also efficiently cooled, there is no breakage even when welding is performed for a long time.

On the other hand, in the present friction welding, a load of about 1000 kg is applied downward by the metal rod 1 during welding. For this reason, a load supporting mechanism 6 for supporting a load is provided inside the cylindrical tube 3.
Is arranged. The load support mechanism 6 can be adjusted to an arbitrary length by a hydraulic pressure 7. Thereby, the tip of the support mechanism 6 can be automatically brought into close contact with the back side of the welded portion 5. Thus, the downward load from the metal rod 1 can be efficiently received, and the cylindrical tube can be welded without deformation and buckling.

(Embodiment 3) FIG. 5 shows a side outer panel 12 of a high-speed vehicle.
Is a perspective view in which a part of is welded by friction heat between the metal rod 1 and a workpiece by the present friction welding method. The side outer plate 12 in this embodiment is an aluminum alloy (standard A6N01) having a length of 25 m, a width of 1 m, and a thickness of 5 mm. As shown in FIG. 5, a nitrogen gas cooled to 5.degree.
Weld while spraying at a flow rate of 0ι / min. The rotation speed of the metal rod is 1000 rpm, and the rotation speed of the workpiece is 200
mm / min. As a result, the welding deformation of the vehicle side outer plate having a length of 25 m is reduced to half that of the conventional friction welding. Furthermore, welding can be performed without a metal rod being worn even by welding with a length of 25 m.

In this embodiment, 1 is used instead of nitrogen gas.
Deformation when using cooling water of 5 ° C is 1/3 of the conventional one.
Has decreased. The side skins welded by the above method are assembled to produce a structure for a high-speed vehicle.

(Embodiment 4) FIG. 6 is a perspective view showing a superconducting coil 13 for a radioisotope being friction-welded in a water tank 14. FIG. 7 shows a cross section of the welded portion in FIG. The superconducting coil 13 has a superconducting wire 15 made of an Nb-Ti alloy embedded in a stabilizer made of pure aluminum. The Nb-Ti alloy superconducting wire 15
Because superconductivity is lost at temperatures above 400 ° C,
It is necessary to weld at 400 ° C. or less. For this reason, in the present invention, friction welding is performed in a 15 ° water tank.

The aluminum stabilizer in this embodiment has a thickness of 8 mm and a width of 15 mm. This is welded in a water bath at 15 ° C. over a length of 500 mm. In this embodiment, the diameter of the tip of the metal rod 1 is 3 mm, and the diameter of the thick part is 12 mm.
This narrow portion is inserted into the butt weld and moves in the direction of the welding line while rotating. The rotation speed of the metal rod is 1000
The rpm and the moving speed are 300 mm / min.

By the friction welding in the water tank, Nb-
The superconducting wire of Ti alloy can be welded at a temperature of 100 ° C. or less. Therefore, sound welding can be performed without deteriorating the superconducting characteristics.

(Embodiment 5) FIG. 8 shows a cross section of a welded portion where a superconducting coil 13 for a radioisotope is friction-welded in a conductor 17 having a copper cooling structure. The conductor 17 has a structure cooled by a water-cooled cooling pipe 16.

The superconducting coil 13 has a superconducting wire 15 made of an Nb-Ti alloy embedded in a stabilizer made of pure aluminum.

The aluminum stabilizer in this embodiment has a thickness of 8 mm and a width of 15 mm. This is welded in a water cooled conductor over a length of 500 mm. The diameter of the tip of the metal rod 1 in this embodiment is 3 mm, and the diameter of the thick part is 12 mm.
It is. This narrow portion is inserted into the butt weld and moves in the direction of the welding line while rotating. The rotation speed of the metal rod is 1000 rpm, and the moving speed is 300 mm / min.

According to the above-described method, the superconducting wire of the Nb-Ti alloy can be friction-welded at a temperature of 300 ° C. or less.

Therefore, sound welding can be performed without impairing the superconducting characteristics.

[0035]

As apparent from the above description, the present invention has the following effects.

1. Since the surroundings of the metal rod and the weld are forcibly cooled by the coolant, deformation of the workpiece after welding and occurrence of welding defects due to the deformation can be reduced. In particular, it is effective for welding a material such as a superconducting wire whose characteristics are deteriorated by temperature.

Further, since the metal rod can also be cooled efficiently, breakage of the metal rod can be prevented even during continuous long-time welding.

2. By arranging a support mechanism whose length can be adjusted arbitrarily on the inner surface of the cylindrical tube, the load in the downward direction by the metal rod can be efficiently received from the inner surface between the cylinders. Can be prevented.

3. In the case of friction welding in the circumferential direction of a cylindrical tube, the position of the metal bar is arranged behind the center of the cylindrical tube with respect to the rotation direction of the cylindrical tube, thereby improving the adhesion between the metal bar and the workpiece surface. Therefore, welding defects can be prevented.

As an application example of the method of the present invention, it can be used for welding a vehicle structure, a cylindrical tube for a gas circuit breaker for transporting electric power, and a superconducting wire coil.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view of FIG. 1 showing an embodiment of the present invention.

FIG. 3 is a perspective view showing an embodiment of the present invention.

FIG. 4 is a sectional view of FIG. 3 showing an embodiment of the present invention.

FIG. 5 is a perspective view showing an embodiment of the present invention.

FIG. 6 is a perspective view showing an embodiment of the present invention.

FIG. 7 is a sectional view of FIG. 6 showing an embodiment of the present invention.

FIG. 8 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal rod, 2 ... Cooling water, 3 ... Cylindrical tube, 4 ... Weld groove, 5 ... Welded part, 6 ... Support mechanism, 7 ... Hydraulic pressure, 8 ... Rail, 9 ... Rotating direction, 10 ... Cylindrical tube , 12 ... side skin for vehicle, 13 ... superconducting coil, 14 ... water tank, 15 ... superconducting wire, 16 ... cooling pipe, 17 ... conductor.

Continued on the front page (72) Inventor Masao Funao 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Kinya Aota 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Koichi Watanabe 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. 1-1 Kokubu Plant, Hitachi, Ltd. (72) Katsuhiko Asano, Inventor 3-1-1 Kochicho, Hitachi City, Ibaraki Prefecture Hitachi Plant, Hitachi, Ltd. (72) Inventor Akihiro Sato Kudamatsu City, Yamaguchi Prefecture 794 Higashi Toyoi Inside the Kasado Plant of Hitachi, Ltd.

Claims (4)

[Claims] A metal rod of a material harder than the material of the workpiece is inserted into a welded portion of the workpiece, and the metal rod is moved while rotating, whereby plastic flow generated in the workpiece is generated. In a friction welding method for welding, the welding is performed while supporting a load by the metal rod by a support means detachably provided on a back surface of the welded portion of the workpiece. 2. A metal rod of a material harder than the material of the workpiece is inserted into the welded portion of the workpiece, and the metal rod is moved while rotating, whereby plastic flow generated in the workpiece is generated. In the friction welding method of welding, the load by the metal rod is supported by support means detachably provided on the back surface of the welded portion of the workpiece, and the welding is forcibly cooled in a coolant. Friction welding method characterized by performing while performing. 3. A plastic flow generated in the workpiece by inserting a metal rod of a material harder than the material of the workpiece into the welded portion of the workpiece and rotating and moving the metal rod. In the friction welding method for welding, while supporting the load by the metal rod by supporting means detachably provided on the back surface of the welding portion of the workpiece, either water or an inert gas is supplied to the welding portion. A friction welding method, wherein the welding is performed while jetting. 4. The work piece is inserted by inserting a metal rod of a material harder than the cylindrical pipe of the work piece into the welded portion of the work piece and moving or moving the work piece while rotating the metal rod. In a friction welding method for a cylindrical pipe, in which the cylindrical pipe is welded in a longitudinal direction or a circumferential direction by a plastic flow generated in an object, the support means detachably provided on a back surface of the welded portion of the work piece. A method for friction welding a cylindrical pipe, wherein the welding is performed while supporting a load by a metal rod and forcibly cooling an inner or outer peripheral surface of the cylindrical pipe.