KR100486370B1 - Friction stir welding method - Google Patents

Abstract

A friction stir welding method is provided to execute friction stir welding at low cost. In a friction stir welding method, abutting parts of a first work(11) and a second work are welded through friction stir welding. The first work and the second work have protruded parts(11a) protruded in a thickness direction of the works in the abutting parts. In the friction stir welding method, friction stir welding is executed while a boundary of a large diameter part(101) and a small diameter part(102) of a rotary tool(100) inserted in the abutting parts from the protruded part side is situated within the protruded part.

Description

Friction Stir Welding Method {FRICTION STIR WELDING METHOD}

The present invention relates to a welding method and apparatus most suitable for arc welding or friction stir welding.

Welding of large structures, such as a car body of a railroad car, is pressed firmly by the fixture which crimps both sides of a workpiece | work welding line. As a pressurization mechanism of a fixture, there are a bolt fastening, an air cylinder, a method of blowing high pressure air into an air hose, and the like. Such is shown in the following document. `` Modern Welding Technology '', Vol. 36, "Easy Automatic, Semi-automatic Welding and Tig Welding" Walk Digestion January 23, 55 pp.248 ~ 249.

In addition, friction stir welding is the joining of a workpiece | work using the rotating joining tool. The tool for joining has a small diameter round rod at the tip of a large diameter round rod, and inserts a small diameter portion into the work to rotate the tool, and moves along the joint line while rotating the solid phase. To join. This is shown in Japanese Patent Laid-Open No. 7-505090 (WO 93/10935), Welding & Metal Fabrication, January 1995 pp. 13-16, and Japanese Patent Application No. 8-322490.

Welding of aluminum alloy is polished and polished with a stainless steel wire wheel because the cleanness of the beveling surface has a great influence on the welding quality. In addition, when it is necessary to remove the debris of a weld bead, it removes with a grinder etc. Because of the additional work of welding, a large work place and a large number of work steps are required.

In order to prevent the work being heated, expanded and deformed by the welding arc heat, and an error occurs in the beveling, the work is crimped and restrained by a fixture and welded (as in the first document). If the work is large, it becomes a large-scale facility and requires a large amount of equipment cost.

In addition, distortion occurs due to welding heat input. When the amount of distortion generated exceeds the allowable amount, distortion is corrected in the rear stroke.

This invention makes it possible to perform welding inexpensively.

The above object can be attained by performing at least substantially the polishing and welding of the beveling, and the cutting of the welding and the tailing at substantially the same time.

(Example)

An embodiment of the present invention will be described with reference to FIGS. This embodiment is a welding device for a roof structure of a vehicle body of a railroad car. The workpiece | work 10 is an extruded material of an aluminum alloy, is arrange | positioned toward the longitudinal direction of a vehicle body, and arrange | positions several in parallel. The workpieces 10 are butt welded to each other so that they can be butt welded together. The workpiece is fixed to the backing sheet 15 of the mount. In addition, the workpieces 10 are temporarily fixed by welding the welding portion 13. Polishing and arc welding of the surface of the beveling surface with the welding head 30 by traveling on the traveling rail 29 in which the welding apparatus 20 of the gutter-shaped door-shaped welding apparatus 20 was installed in the longitudinal direction. And removing the debris of the weld bead in one stroke of the welding device 20. The welding head 30 is as many as the number of welding lines. The backing sheet 15 is comprised so that the workpiece | work 10, 10 ... may be a normal finishing state.

The welding head 30 may move the girders 21 of the welding apparatus 20 in the girders longitudinally and at the same time move up and down. Each of the welding heads 30 may be independently moved or lifted.

The welding head 30 is a polishing apparatus 40 for polishing and removing the coating or contamination on the surface of the beveling surface in order from the front of the welding progress direction, and a suction for sucking and removing the debris generated by polishing. Cutting to cut the population 47, the sensor 50 for detecting the position of the beveling, the crimping device 60 of the weld, the welding torch 55, the crimping device 80 of the weld, and the bead of the weld bead An apparatus 90 and a suction port 97 for sucking cutting chips are provided.

These are provided in the sheet 31. The column 32 is raised and lowered to determine the position relative to the work 10. The sensor 50 detects the beveling of the workpiece and moves the sheet 31 in the width direction of the workpiece 10 so that the torch 70 is positioned at a predetermined position.

The polishing apparatus 40 is composed of a wire wheel 42, an air motor for rotating it, and the like. As the air motor 43 rotates, the bevel gear 44 and the spur gears 45 and 46 rotate to rotate the wire wheel 42. The sheet 41 of the polishing apparatus 40 is elevated by the elevating device 48. The elevating device 48 consists of a screw rod and a nut, and elevates by rotating the handle 48a.

The wire wheel 8 is a radially planted stainless steel wire with a wire wire diameter of 0.15 ~ 0.25mm. The film residue of the surface generated by grinding the beveling surface and the polishing residue of the contamination are sucked by the suction port 47 provided in the rear portion of the wire wheel 42.

The sensor 50 irradiates a laser beam to a beveling, and photographs the image with a CCD camera to always automatically follow the position of the welding torch 55 and the beveling at a predetermined distance.

The crimping devices 60 and 80 press (press) the workpiece 10 to the backing sheet 15. The crimping device 60 prevents the workpiece 10 heated by the arc of the welding torch 55 from expanding and deforming to cause an error in the beveling. Pressurization by the crimping devices 60 and 80 is performed with the air cylinders 61 and 81. The contact with the workpiece | work 10 is the rolls 62 and 82 of the crimping apparatus 60 and 80. As shown in FIG.

The crimping effect of the workpiece is greater as it approaches the molten pool of the weld. However, when the roll approaches the molten pool, the rolls 62 and 82 are overheated to a high temperature by arc heat and deteriorate in a short time. Thus, cooling mechanisms for the rolls 62 and 82 are provided.

There are a plurality of rolls 62 of the crimping device 60, and both sides of all the rolls 62, 62 are connected to each other via the joint plate 63 via the pins 64, and are constituted by endless belts. This endless belt is supported by the support sheet 65. The support sheet 65 is divided into two in the axial direction of the roll 62. It has a convex part 65a which contacts the inside of a ring shaped endless belt. The upper surface of the lower roll 62 is in contact with the convex portion 65a by pressing the roll 62 onto the work 10. The lower surface of the roll 62 above the convex portion 65a is in contact with the upper surface of the convex portion 65a. The support sheet 65 is provided with a passage 66 for cooling water. The cooling water passage 66 may also be provided in the convex portion 65a.

The roll 62 presses the left and right workpieces 10 and 10. There are a plurality of rolls 62, and a plurality of rolls 62 are always in contact with the workpiece 10. The material of the roll 62, the support sheet 65, and the partition board 69 is copper alloy with high thermal conductivity and high hardness.

When the welding head 30 moves along the workpiece | work 10, the endless belt of the roll 62 rotates. At this time, the roll 62 is in contact with the cooled support sheet 65 and cooled.

The partition board 69 is arrange | positioned between the convex part 65a and the convex part 65a. The outer circumferential edge of the partition plate 69 enters the recessed portion of the center of the roll 62. Thereby, the positioning of the roll 62 is performed. The two support sheets 65 and 65 are integrally fastened by a plurality of bolts and nuts 68.

Adjustment of the pressing force of the workpiece | work 10 by the roll 62 is performed by adding or subtracting the air pressure of the air cylinder 61. As shown in FIG.

The crimping device 80 behind the welding torch 55 prevents the entire work 10 from rising from the backing sheet 15. For this purpose, it is not necessary to approach and install the welding torch 55 as much as the crimping device 60 in front of the welding torch 55. However, also in this case, since the roll 82 is heated to high temperature, it is necessary to cool. The roll 82 is provided with the recessed part for preventing contact with a welding bead in the center part of the axial direction. The roll 82 compresses the left and right workpieces 10 and 10. The roll 82 is rotatably provided in the flange 85a of the support sheet 85 with the pin 84 via the heat conductor 83 which has a flange at the edge part of a cylinder part. The pin 84 is fixed to the flange 85a with the screw 87. As shown in FIG. The support sheet 85 is cooled by passing water through the passage 86 of the cooling water. The heat conductor 83 is divided into left and right, and the flange is in contact with the flange of the roll 82 and the support sheet 85. The material of the roll 82, the heat conductor 83, the support sheet 85, and the fin 84 is a copper alloy with high thermal conductivity and high hardness.

Adjustment of the pressing force of the workpiece | work 10 by the roll 82 is performed by adjusting the air pressure of the air cylinder 81.

The cutting apparatus 90 consists of the end mill 92 and the electric motor 93 which rotates it. The cutting device 90 is elevated by the air cylinder 81. For this reason, the cutting device 90 is provided near the pressing device 80.

Suction ports 47 and 97 are connected to a vacuum apparatus via a hose. Reciprocating water hoses are connected to the water passages 66 and 86 of the crimping devices 60 and 80. These hoses are supported by the upper girder and the like.

In such a configuration, after fixing the workpieces 10 and 10 to the backing sheet 15, the heights of the polishing apparatus 40, the pressing apparatuses 60 and 80, and the cutting apparatus 90 are set, and each is driven. The welding head 30 is moved from the upstream to the downstream along the welding line.

The wire wheel 42 of the polishing apparatus 40 polishes the beveling, and the polishing dregs are sucked out of the nozzle 47. The rollers 62 and 82 of the crimping devices 60 and 80 compress the vicinity of the beveling. The heat input is taken away by the rolls 62 and 82 contacting the support sheets 65 and 85. The weld bead is cut at the lower end of the end mill 92 of the cutting device 90. The cutting debris is sucked into the nozzle 97.

In this manner, the welding head 30 can be polished, welded, and cut by one stroke movement. In addition, the device can be made small, and the required place can be made small.

The rolls 62 and 82 of the crimping devices 60 and 80 are forcibly cooled by the contact with the support sheets 65 and 85. For this reason, crimping | compression-bonding does not become inadequate due to the inability to rotate a roller conventionally, and the step (layer difference) of the workpiece | work 10 of the weld part 10 does not arise. In addition, the lower end position of the end mill 92 also becomes constant.

Since the welding torch 55 faces the front of the movement direction of the welding head 30, the front side of the crimping | compression-bonding apparatus 60 becomes high temperature. The roll 62 of this crimping device 60 is provided with endless belts, and the contact time with the support sheet 65 is lengthened. For this reason, compared with the crimping device 80, the roll 62 is cooled well.

The sensor 50 raises and lowers the column 32 by detecting the height position of the beveling. Moreover, the air cylinders 61 and 81 which raise and lower the crimping devices 60 and 80 and the cutting device 90 are pushed down by predetermined pressure, and can move up and down slightly by reaction force from the workpiece side.

The cutting means of the cutting device 90 is the end mill 92. For this reason, the cutting device can be made compact and very inexpensive. In addition, in the mechanical cutting by the cutting device 90, in order to prevent excessive cutting, the upper part of the workpiece 10 is cut slightly above. After cutting by the welding head 30, the upper surface and the surface of a workpiece are finished by hand by a grinder similarly. When the cutting by the cutting device 90 is unnecessary, the end mill 92 is removed.

The generation of welding distortion due to arc welding can be alleviated by eliminating the bite immediately after welding. 6 shows the amount of distortion generated in the case where the debris is removed by a grinder after completely cooling (room temperature) after welding and when the debris is deleted by the end mill 92 at a high temperature immediately after welding. Material: A5083P-0, Plate thickness: 4mm, Width: 150mm, Length: 1000mm Work with MIG welding current: 180A, arc voltage: 22V, welding speed: 50cm / min, welding wire diameter: 1.2mm Was performed. The distortion amount δ was about 9 mm for the former and about 7 mm for the latter. In addition, the position of the end mill 92 is about 300 degreeC.

As the rolls 62 and 82 roll the upper surface of the work 10, the air cylinders 61 and 82 receive a bending force. For this reason, the linear guide apparatus may be provided between the air cylinders 62 and 82 and the support sheets 65 and 85. FIG.

The above embodiment was the case of arc welding, but can also be applied to friction stir welding. In this case, since it is a solid state joining, it does not become high temperature as much as arc welding. The forced cooling means of the crimping devices 60 and 80 are installed as needed. The polishing apparatus 40 and the cutting apparatus 90 can be applied similarly.

In addition, friction stir welding is demonstrated by FIG. The end of the work 11 has a projection 11a that protrudes to the outer surface side (that is, the tool 100 side of friction stir welding).

The thick portion 11a is inclined as it goes to the inside of the work 11. The end of the work 11 is vertical. These two workpieces 11 and 11 face each other. The tool 100 consists of a large round rod 101 and a small round rod 102 of its tip. While rotating the tool, the small diameter portion 102 is placed in the butt portion and moved along the joint line. The lower end of the large diameter portion, that is, the boundary between the small diameter portion 102 and the large diameter portion 101 is located outside the upper surfaces of the plate portions 11b and 11b of the work 11 and is located inside the protrusions 11a and 11a.

Part of the workpieces 11 and 11 is cut out by the boundary. In this way, in order to smoothly finish the surface of the work 11, welding (joining) may be performed in the state of the toothing (with the protrusions 11a), and then the toothing may be cut thereafter.

According to the present invention, friction stir welding can be performed at low cost.

1 is a side view of a welding head in one embodiment of the present invention;

2 is an overall perspective view of a welding apparatus with the welding head of FIG. 1, FIG.

3 is an enlarged side view of a welding part crimping device of the welding head of FIG. 1;

4 is a longitudinal sectional view of FIG. 3;

5 is a longitudinal sectional view of the crimping apparatus of the welding head of FIG. 1;

6 is an overall view of a workpiece for explaining welding distortion;

7 is a longitudinal sectional view of a welded part of another embodiment of the present invention.

※ Explanation of symbols for main parts of drawing

10, 11: Walk 15: Backing sheet

20: welding apparatus 30: welding head

40: polishing apparatus 42: wire wheel

47, 97: suction port 50: sensor

55: welding torch 60, 80: crimping device

62, 82: roll 92: end mill

100: rotary tool

Claims (1)

In a method of friction stir welding abutting portions of a first workpiece and a second workpiece, The first workpiece and the second workpiece have protrusions protruding in the thickness direction of the workpiece at the abutting portion, Friction stir welding method characterized in that the friction stir welding is carried out in the state where the boundary between the large diameter portion and the small diameter portion of the rotary tool inserted into the butt portion from the projection portion is located in the projection portion.