CN104999173B - Thin-walled aluminum alloy pipe end sealing and welding device and welding method - Google Patents

Abstract

The invention discloses a thin-walled aluminum alloy tube end sealing welding device and a welding method. The sealing welding device includes a roller frame group for supporting the thin-walled aluminum alloy tube and the aluminum alloy rod. One end of the aluminum alloy rod is installed by The hollow chuck on the rotary fixture is fixed. One end of the aluminum alloy rod passing through the chuck is equipped with a tip, and the other end of the aluminum alloy rod is a shaft body with a diameter smaller than the aluminum alloy rod. The shaft body and the aluminum alloy rod form a shoulder. The shaft body is inserted into the thin-walled aluminum alloy tube, and the shaft body and the thin-walled aluminum alloy tube are interference fit. A stirring head is installed above the thin-walled aluminum alloy tube, and the end of the thin-walled aluminum alloy tube is sealed and welded through the H-shaped weld. The invention provides a thin-walled aluminum alloy tube end sealing welding device, which uses H-shaped welds to complete welding at one time, which ensures the accuracy of the appearance of the weldment and at the same time ensures the quality of welding and the airtightness of the aluminum alloy tube.

Description

A thin-walled aluminum alloy pipe end sealing welding device and welding method

technical field

The invention relates to a thin-walled aluminum alloy pipe end sealing welding device and a welding method, belonging to the field of metal material processing.

Background technique

Friction Stir Welding (FSW for short) is a patented welding technology invented by The Welding Institute in 1991. In addition to the advantages of ordinary friction welding technology, friction stir welding can also connect various joint forms and different welding positions. Friction stir welding technology has been successfully applied in aviation, aerospace, ships, trains, electric power and heavy weapons. However, there are still some problems in the welding of thin-walled aluminum alloy tubes.

When the pipe wall becomes smaller, the difficulty of welding becomes greater. Patent (201410729971.X) proposes the use of tungsten inert gas shielded welding to solve the connection problem of small-diameter thin-walled aluminum alloy pipes; patent (201010524846.7) proposes a welding method for small-diameter nozzles and aluminum alloy thin-walled structures. The small-diameter nozzle is welded at the junction of the aluminum alloy thin-walled structure, and arc welding is also used for welding. In fact, when welding aluminum alloys by arc welding (such as AC tungsten argon arc welding), it is easy to cause cracks and pores, especially when welding thin-walled pipe fittings, the welding deformation is more serious, and the scrap rate even reaches 70%. In order to improve the welding quality, the patent (201310096100.4) proposes a production method of small-diameter ultra-thin-wall high-frequency welding aluminum alloy tubes for heat pumps, but the welding current is high, reaching 230-235A, and the electrical efficiency of high-frequency welding is low ( About 50%), the working voltage and current are too high, and the safety is poor. Zheng Ying et al. (Patent No.: 201510118191.6, 201510118211.X) proposed a production method of aluminum alloy ultra-large-diameter thin-walled pressure-resistant pipes, using friction stir welding for longitudinal seam welding. But there is no end face sealing welding technology involving aluminum alloy tubes. Li Hui et al. (from: AWJT2005, October 20-23, Dalian, China, A42-A47) proposed a friction stir welding method for thin-walled aluminum alloy cylinder welds, but in the welding process, internal tension is required. The equipment ensures that the weldment is not deformed, and the end cap needs to be tightened from both sides, and the proposed method is suitable for the case where the end face of the aluminum alloy cylinder has an opening, that is, when the end face is required to be completely closed, the proposed method will not be able to complete Task.

It can be seen that when the thin-walled aluminum alloy pipe (with a wall thickness less than 1 mm) needs to be welded with closed end faces, it faces welding problems, which are reflected in: 1. The thin wall thickness leads to poor rigidity and torsion resistance, and it is difficult to directly clamp and rotate welding; 2. The requirement of closed aluminum alloy end faces makes it difficult for the internal tensioning device to be placed inside the thin-walled pipe fittings, resulting in the failure of friction stir welding due to the lack of internal support. Therefore, it has important practical significance to propose an effective thin-walled aluminum alloy pipe end sealing welding method and device.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a thin-walled aluminum alloy pipe end sealing welding device and welding method, which uses H-shaped welds to complete the welding at one time, ensuring the accuracy of welding and at the same time Ensure the quality of welding and the airtightness of aluminum alloy tubes.

Technical solution: In order to solve the above technical problems, a thin-walled aluminum alloy tube end sealing welding device of the present invention includes a roller frame group for supporting the thin-walled aluminum alloy tube and the aluminum alloy rod, and one end of the aluminum alloy rod passes through the The hollow chuck installed on the rotating fixture is fixed. One end of the aluminum alloy rod passing through the chuck is equipped with a tip, and the other end of the aluminum alloy rod is a shaft body with a diameter smaller than the aluminum alloy rod. The shaft body and the aluminum alloy rod form a shoulder. The shaft body is inserted into the thin-walled aluminum alloy tube. The shaft body and the thin-walled aluminum alloy tube are interference fit. A stirring head is installed above the thin-walled aluminum alloy tube. Through friction stir welding, a H is formed on the thin-walled aluminum alloy tube. Type welds.

Preferably, the interference between the shaft body and the thin-walled aluminum alloy tube is δ, δ=(tt ₀ )×α×l-δ ₀ , where δ ₀ =(1～2)*δ, t is the assembly t ₀ is the ambient temperature before heating, α is the radial expansion coefficient of the workpiece during heating, l--the inner diameter of the heated hole.

Preferably, the length of the shaft body is not less than 3.5 times the diameter of the stirring head, and the length of the stirring needle is not less than 1.5 times the wall thickness of the thin-walled aluminum alloy tube.

Preferably, the H-shaped weld includes a first girth weld and a second girth weld, the first girth weld completes the lap welding of the aluminum alloy tube and the shaft shoulder, and the second girth weld completes Butt welding of aluminum alloy tubes and aluminum alloy rods.

A welding method of the above-mentioned thin-walled aluminum alloy pipe end sealing welding device, comprising the following steps:

(1) According to actual needs, use δ=(tt ₀ )×α×l-δ ₀ to determine the interference δ and the diameter of the shaft body, select the appropriate length of the shaft body, and process the aluminum alloy rods that meet the requirements. Choose the appropriate length of the stirring needle for the wall thickness of the aluminum alloy tube;

(2) Heat the thin-walled aluminum alloy tube to 100°C, then quickly assemble the thin-walled aluminum alloy tube and aluminum alloy rod, and air-dry after rapid cooling;

(3) Pass the assembled workpiece through the rotating fixture and fix it with a chuck, and install the rest on the roller frame group to run with the rotating fixture. Adjust the stirring head so that it is vertically aligned with the thin-walled aluminum alloy tube and aluminum alloy rod The central axis, and the distance between the center of the stirring head and the edge of the shaft body should be greater than or equal to D, where D is the diameter of the stirring head, and the stirring needle is located directly above the end of the shaft body;

(4) Start the stirring head first, and make it slowly press into the area to be welded for preheating. After the preheating is over, start to rotate the chuck. When the chuck rotates for one week, the welding of the lap weld seam is completed, and stop at this time. With the rotation of the chuck, the stirring needle continues to rotate at a high speed and welds horizontally to the side of the aluminum alloy rod along the axis of the aluminum alloy rod for a certain distance until the joint between the aluminum alloy tube and the aluminum alloy rod stops moving, and the welding of the butt ring weld is ready to start;

(5) Slowly rotate the chuck again and the direction of rotation is the same as before. When the welding of the butt ring weld is completed after the chuck rotates one week, the rotation of the chuck is stopped at this time, and the stirring head continues to rotate at a high speed and moves to the side of the aluminum alloy rod After moving horizontally for a short distance, slowly lift the stirring head until the stirring needle is completely separated from the weld, then stop the rotation of the stirring head, and the welding of the side pipe end is completed;

(6) Process the same shaft body according to steps (1) and (2), and assemble the thin-walled aluminum alloy tube and aluminum alloy rod;

(7) Repeat steps (3) to (5) once again for the assembled thin-walled aluminum alloy tube and aluminum alloy rod to complete the sealing and welding of both ends of the thin-walled aluminum alloy tube.

As a preference, in the step (4) or step (5), the stirring head and the aluminum alloy rod observe the rotation direction of the chuck along the positive direction of the X axis, and observe the rotation direction of the stirring head along the negative direction of the Z axis, if the chuck If it rotates counterclockwise, the stirring needle must rotate clockwise or if the chuck rotates clockwise from the perspective of the left view, then the stirring needle must rotate counterclockwise from the perspective of the top view, where the X axis is an aluminum alloy rod The axis of the axis, away from the thin-walled aluminum alloy tube is the positive direction, the Z axis is the axis of the stirring needle, and the direction away from the aluminum alloy rod is the positive direction.

In the present invention, the thin-walled aluminum alloy tube does not use clamping or supporting devices, but only interferes with the aluminum alloy rod to ensure that during the initial welding, on the one hand, the aluminum alloy tube and the aluminum alloy rod can be closely fitted; on the other hand On the one hand, the axial relative movement between the two is prevented by interference fit; during normal welding, the completed weld will gradually strengthen the connection strength between the aluminum alloy tube and the aluminum alloy rod. Compared with the method commonly used in machinery, the choice of this interference fit does not require a large amount of interference. The stirring needle is inserted into the lap weld, and the stirring needle itself acts as a "pinning" function, and does not require too strong In addition, the interference fit is at a high temperature (about 500°C) during the welding process. Excessive interference will cause strong tensile stress on the aluminum alloy tube, which is not conducive to weld formation. . When selecting the interference of conventional aluminum alloy materials, since aluminum alloy is softer than steel at a temperature of 100°C, a larger interference is required.

Beneficial effects: the thin-walled aluminum alloy pipe end sealing welding device and welding method of the present invention have the following advantages:

(1) It can effectively complete the welding task of thin-walled pipe ends, especially suitable for the special requirements of pipe end sealing;

(2) Do not use the internal tensioning device, do not tighten the two ends of the thin-walled aluminum alloy tube to fix it, use the heating of the thin-walled aluminum alloy tube to expand the thin-walled aluminum alloy tube, and insert the aluminum alloy rod into the thin-walled aluminum alloy tube Among them, it overcomes the shortcomings of low rigidity and poor torsion resistance of thin-walled pipe fittings, and has versatility in the welding of thin-walled pipe fittings made of other materials;

(3) The H-shaped weld is used to complete the welding at one time, which not only ensures the accuracy of the welding, but also ensures the quality of the welding and the airtightness of the aluminum alloy tube;

(4) The structure is simple and practical, and the method and device are easy to implement and easy to assemble, which has important practical significance for the application of thin-walled aluminum alloy pipe end sealing welding.

Description of drawings

Figure 1 is an overall schematic diagram of a thin-walled aluminum alloy pipe end sealing welding device;

Figure 2 is the front view of the H-shaped weld;

Figure 3 is a schematic diagram of the A-A section of the H-shaped weld;

Figure 4 is a schematic diagram of a cross-sectional structure of a welded joint;

Figure 5 is a schematic diagram of the position of the forward side and the backward side;

Fig. 6 is a schematic diagram of the cooperation between the workpiece to be welded and the rotation direction of the stirring needle.

In Fig. 1, 1-aluminum alloy tube; 2-stirring needle; 3-stirring head; 4-H-shaped weld; 5-aluminum alloy rod; -Tip; 10 shaft body; 4-2 Transition weld from the first girth weld to the second girth weld in the H-type weld; 4-1 is the first girth weld in the H-type weld; 4 -3 is the second girth weld in the H-shaped weld.

detailed description

As shown in Figures 1 to 6, a thin-walled aluminum alloy tube end sealing welding device according to the present invention includes a roller frame group 7 for supporting the thin-walled aluminum alloy tube 1 and the aluminum alloy rod 5, the aluminum alloy rod One end of 5 is fixed by the hollow chuck 6 installed on the rotating fixture 8, and the tip 9 is installed on one end of the aluminum alloy rod 5 passing through the chuck 6, and the other end of the aluminum alloy rod 5 is a shaft body whose diameter is smaller than that of the aluminum alloy rod 5 10. The shaft body 10 and the aluminum alloy rod form a shoulder, the shaft body 10 is inserted into the thin-walled aluminum alloy tube 1, the shaft body 10 and the thin-walled aluminum alloy tube 1 are interference fit, and are installed above the thin-walled aluminum alloy tube 1 There is a stirring head 3, and the stirring needle 2 is integrated with the stirring head 3 to form an H-shaped weld 4 on the thin-walled aluminum alloy pipe 1.

In the present invention, the interference between the shaft body 10 and the thin-walled aluminum alloy tube 1 is δ, δ=(tt ₀ )×α×l-δ ₀ , where δ ₀ =(1～2)*δ , t is the temperature during assembly, t ₀ is the ambient temperature before heating, α is the radial expansion coefficient of the workpiece during heating, l--the inner diameter of the heated hole. The length of the shaft body 10 is not less than 3.5 times the diameter of the stirring head 3, and the length of the stirring needle 2 is not less than 1.5 times the wall thickness of the thin-walled aluminum alloy tube 1. The first girth weld 4-1 of the H-shaped weld 4 completes the lap welding of the aluminum alloy tube 1 and the shaft shoulder, and the second girth weld 4-3 of the H-shaped weld 4 completes the aluminum alloy tube 1 For butt welding with aluminum alloy rods, the first girth weld 4-1 to the second girth weld 4-3 in the H-shaped weld is the transition weld 4-2.

Wherein, the stirring pin 2 on the stirring head 3 is rigidly fixedly connected, and the rotating action, X-axis, Y-axis, and Z-axis adjustment functions of the stirring head 3 can all be realized by friction stir welding machines on the market, wherein the X-axis is The axis of the aluminum alloy rod is positive away from the thin-walled aluminum alloy tube, and the Z axis is the axis of the stirring needle, and the positive direction is away from the aluminum alloy rod. The X-axis is the longitudinal movement of the stirring head 3 to realize the rapid positioning of the welding seam, and adopts "servo motor + ball screw + linear ball guide" to drive. The Y-axis is the horizontal movement of the stirring head 3, which realizes the adjustment of the stirring head 3 and the lateral position and loading and unloading of the stirring head 3, and adopts "manual trapezoidal screw + linear ball guide rail" transmission. The Z-axis is the vertical movement of the main shaft head to realize the insertion of the stirring head 3, which is driven by "servo motor + worm reducer + ball screw". The rotating shaft of the welding fixture realizes the rotation of the aluminum alloy rod 5 and the aluminum alloy tube 1, and is driven by a "servo motor+cycloidal pinwheel reducer". The rotating shaft of the stirring head 3 can be directly driven by a motor.

In the present invention, the chuck 6 is fixed on the rotating fixture 8, and the chuck 6 is used to clamp the aluminum alloy rod 5, and the rotating fixture 8 must be hollow and capable of passing through the aluminum alloy rod. The top 9 is mainly used to promote the feeding of the aluminum alloy rod, so the piston-type pneumatic top 9 is selected and the driving force of the selected pneumatic top 9 can be small. The roller frame group 7 can adjust the distance between the rollers in the Y direction to adapt to pipes with different diameters.

Regarding the definition of the forward side and the backward side: during welding, both the workpiece and the stirring head are rotating, because the direction of motion of any point on the rotating object is tangential to the circle where it is located. As shown in Figure 5, therefore when the circumferential tangential direction of the metal at the welded area on the surface of the circular tube workpiece is the same as the tangential direction on the circumference of the stirring head (corresponding to the tangential direction 15), the centerline of the weld seam 12 on the workpiece is boundary, this side is the receding side; when the circumferential tangential direction of the metal at the welding area on the surface of the circular pipe workpiece is opposite to the tangential direction on the circumference of the stirring head (corresponding to the tangential direction 16), the weld seam centerline 12 on the workpiece As the boundary, this side is the advancing side. Determine the rotation direction of the stirring head 3 and the chuck 6: the axial position sequence of the advancing side of the weld seam relative to the retreating side should be the same as the axial position sequence of the aluminum alloy rod relative to the aluminum alloy tube, as shown in Figure 6 . Assuming that the rotation direction of the chuck 6 is observed from the perspective of the left view, and the rotation direction of the stirring head 3 is observed from the perspective of the top view, if the chuck 6 rotates counterclockwise, the stirring needle 2 must rotate clockwise; The chuck 6 rotates clockwise from the perspective of the left view, and the stirring needle 2 must rotate counterclockwise from the perspective of the top view.

A welding method of the above-mentioned thin-walled aluminum alloy tube 1-end sealing welding device, comprising the following steps:

(1) According to actual needs, use δ=(tt ₀ )×α×l-δ ₀ to determine the interference δ and the diameter of the shaft body 10, select the appropriate length of the shaft body 10, and process the aluminum alloy rod 5 that meets the requirements, Select a suitable stirring needle 2 according to the wall thickness of the thin-walled aluminum alloy tube 1;

(2) Heat the thin-walled aluminum alloy tube 1 to 100° C., then quickly assemble the thin-walled aluminum alloy tube 1 and the aluminum alloy rod 5 and air dry after rapid cooling;

(3) Pass the assembled workpiece through the rotating fixture 8 and fix it with the chuck 6, and install the rest on the roller frame group 7 to run with the rotating fixture 8, adjust the stirring needle 2 to align it vertically downward with the thin-walled aluminum alloy The central axis of the tube 1 and the aluminum alloy rod 5, and the distance between the stirring needle 2 and the edge of the shaft body must be greater than or equal to D, where D is the diameter of the stirring head 3, and the stirring needle 2 is located directly above the end of the shaft body 10;

(4) Start the stirring head 3 first, and make it slowly press into the area to be welded for preheating, start to rotate the chuck 6 after the preheating ends, and when the chuck 6 rotates for one week, the welding of the lap weld seam is completed, Stop the rotation of the chuck 6 at this time, and the stirring pin 2 continues to rotate at a high speed and welds horizontally to the side of the aluminum alloy rod along the axis of the aluminum alloy rod for a certain distance, until the joint between the aluminum alloy tube 1 and the aluminum alloy rod stops moving, and is ready to start docking Welding of girth welds;

(5) Slowly rotate the chuck 6 again and the direction of rotation is the same as before. After the chuck 6 rotates for one week, the welding of the butt girth weld is completed. At this time, the rotation of the chuck 6 is stopped, and the stirring head 3 continues to rotate at a high speed and moves toward the aluminum After one side of the alloy rod moves horizontally for a short distance, slowly lift the stirring head 3 until the stirring needle 2 is completely separated from the weld, then stop the rotation of the stirring head 3, and the welding of the side pipe end is completed;

(6) Process the same shaft body 10 according to steps (1) and (2), and assemble the thin-walled aluminum alloy tube 1 and the aluminum alloy rod;

(7) Repeat the steps (3) to (5) once again for the assembled thin-walled aluminum alloy tube 1 and the aluminum alloy rod to complete the sealing and welding of both ends of the thin-walled aluminum alloy tube 1 .

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (5)

1. a thin-wall aluminum alloy pipe end soldering and sealing device, it is characterised in that: include for supporting thin-wall aluminum alloy pipe and aluminium alloy The turning rolls group of rod, the chuck of the one end of described aluminium alloy bars the hollow by being arranged on rolling clamp fixes, aluminium alloy bars One end through chuck is provided with top, and the aluminium alloy bars other end is the axle body that diameter is less than aluminium alloy bars, axle body and aluminium alloy Rod becomes the shaft shoulder, axle body to be inserted in thin-wall aluminum alloy pipe, and axle body and thin-wall aluminum alloy pipe are interference fit, at thin-wall aluminum alloy Pipe is arranged above stirring-head, is welded by agitating friction, forms H type weld seam, thus realize Thin-walled Aluminum on thin-wall aluminum alloy pipe The soldering and sealing of alloy pipe end；Described axle body is δ, δ=(t-t with the magnitude of interference of thin-wall aluminum alloy pipe₀)×a×l-δ_O, wherein, δ₀= The temperature of thin-wall aluminum alloy pipe, t when (1～2) * δ, t is assembling₀For the ambient temperature before heating, the radial direction of workpiece when α is heating The coefficient of expansion, l--is heated the internal diameter in hole.

Thin-wall aluminum alloy pipe end soldering and sealing device the most according to claim 1, it is characterised in that: the length of described axle body is the least In 3.5 times of stirring-head diameter, the mixing needle length thin-wall aluminum alloy thickness of pipe wall not less than 1.5 times.

Thin-wall aluminum alloy pipe end soldering and sealing device the most according to claim 2, it is characterised in that: described H type weld seam includes One girth joint and second girth joint, first girth joint completes the overlap welding of aluminium-alloy pipe and the shaft shoulder, second boxing Stitch the butt welding of aluminium-alloy pipe and aluminium alloy bars.

4. the welding method of a thin-wall aluminum alloy pipe end soldering and sealing device described in claim 3 as mentioned, it is characterised in that Comprise the following steps:

(1) δ=(t-t according to actual needs, is utilized₀)×α×l-δ₀Determine the diameter of magnitude of interference δ and axle body, choose suitable axle Body length, processes satisfactory aluminium alloy bars, selects the length of suitable mixing needle according to thin-wall aluminum alloy thickness of pipe wall；

(2) thin-wall aluminum alloy pipe is heated to 100 DEG C, assembles the most rapidly thin-wall aluminum alloy pipe and aluminium alloy bars and quickly cool down Rear air-dried；

(3) through rolling clamp and being fixed with chuck by the workpiece assembled, remainder is then arranged in turning rolls group with rotation Turn fixture operating, adjust stirring-head and make it be directed at the axis of thin-wall aluminum alloy pipe and aluminium alloy bars vertically downward, and stir The distance of the off-axis edge at one's side of needle gage is greater than equal to D, and wherein D is the diameter of stirring-head, and stirring-head is positioned at just going up of axle body end Side；

(4) first starting stirring-head, and make it slowly be pressed into be preheated by welding zone territory, preheating starts rotary chuck after terminating, The welding overlapping girth joint after chuck rotates a circle completes, and now stops the rotation of chuck, and mixing needle continues to keep turning at a high speed Move and weld a segment distance along aluminium alloy bars axis to aluminium alloy bars side level, until aluminium-alloy pipe docks with aluminium alloy bars Place stops mobile, prepares to start the welding of butt girth welding seam；

(5) again slowly rotating chuck and direction of rotation with the most consistent, the welding of butt girth welding seam after chuck rotates a circle Completing, now stop the rotation of chuck, stirring-head continues to keep high-speed rotation and moves horizontally one to aluminium alloy bars side little After segment distance, slowly promoting stirring-head, until mixing needle stops the rotation of stirring-head again after completely disengaging from weld seam, this side pipe end welds Access node bundle；

(6) according to step (1) and (2), process identical axle body, assemble thin-wall aluminum alloy pipe and aluminium alloy bars；

(7) again the thin-wall aluminum alloy pipe assembled and aluminium alloy bars are repeated step (3) to (5), Thin-walled Aluminum can be completed The soldering and sealing at compo pipe two ends.

The welding method of thin-wall aluminum alloy pipe end soldering and sealing device the most according to claim 4, it is characterised in that: described step (4) stirring-head and aluminium alloy bars observe the direction of rotation of chuck along X-axis forward or in step (5), observe along Z axis negative sense simultaneously The direction of rotation of stirring-head, if chuck counterclockwise rotates, then mixing needle must be rotated clockwise；Or chuck side clockwise To rotation, then mixing needle must counterclockwise rotate, and wherein, X-axis is the axis of aluminium alloy bars, away from thin-wall aluminum alloy Guan Weizheng To, Z axis is the axis of mixing needle, is forward away from aluminium alloy bars.