Friction stir welding device and method suitable for high-melting-point metal

Abstract

The invention discloses a friction stir welding device and method suitable for high-melting-point metal. The friction stir welding device and method aim at improving the fluidity of the high-melting-point metal such as steel in the friction stir welding process, improving the strength of a welding joint, reducing abrasion of a stirring tool and reducing the production cost. The welding device comprises a non-rotating part, a rotating part and an inclined table top, and the bottom face of the non-rotating part is provided with an inclined face matched with the inclined table top. The rotating part is installed in the non-rotating part. The inclined table top is matched with the inclined face of the non-rotating component, the material flowability is improved by means of the material flow velocity difference caused by the height difference between the welding advancing side and the welding retreating side, the fixed shaft shoulder structure with the side inclination angle compacts, trowelds and welds the peripheral plasticized material, the profile precision after welding and the welding quality are improved, and the welding quality is improved. Meanwhile, the stirring tool is made of high-hardness and low-cost materials such as ceramic, so that the production cost is greatly reduced. The invention belongs to the technical field of friction stir welding.

Description

Technical Field

[0001] The present invention relates to a welding device and method, and particularly to a friction stir welding device and method suitable for high melting point metals. The present invention belongs to the technical field of friction stir welding. Background Art

[0002] With the rapid development of manufacturing industries such as aerospace, automotive, and shipbuilding, traditional fusion welding technologies are facing problems such as welding cracks, pores, degradation of the heat affected zone, and decline in mechanical properties, making it difficult to meet the requirements of high-efficiency and high-quality manufacturing. Friction stir welding uses a rotating tool to generate frictional heat between workpieces and stirs and mixes the materials through the feeding force of the tool to form a high-strength joint. During the processing, the materials are not completely melted and remain in a near-solid state for plastic flow, thus avoiding the common defects in fusion welding.

[0003] However, the application of friction stir welding to high melting point metals poses certain challenges. Firstly, due to the high strength and low plasticity of high melting point metals, their plastic fluidity during the welding process is not as good as that of low melting point metals such as aluminum alloys, which increases the welding difficulty. Secondly, high melting point metal materials have a high hardness, which makes the stirring tool prone to wear, and usually high wear-resistant and high thermal stability materials need to be used. The application of these materials is limited by high costs and large processing difficulties.

[0004] Based on the above problems, if a new friction stir welding device can be designed to tilt the processing table to promote the flow behavior of materials during welding and use high-hardness and low-cost materials such as ceramics to manufacture the stirring tool, it will promote the application progress of friction stir welding technology in the field of high melting point metal materials. Summary of the Invention

[0005] The present invention aims to improve the fluidity during the friction stir welding of high melting point metals such as steel, increase the strength of the welded joint, reduce the wear of the stirring tool, and lower the production cost. Therefore, a friction stir welding device and method suitable for high melting point metals are proposed.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows:

[0007] The welding device of the present invention includes a non-rotating component, a rotating component, and an inclined table. The non-rotating component includes a clamping portion, a stepped portion, and a shoulder portion. The stepped portion is a hollow structure, with a clamping portion provided at its upper end and a shoulder portion provided at its lower end. An inclined surface matching the inclined table is provided on the bottom surface of the shoulder portion. The rotating component is installed in the stepped portion and includes a rotating clamping portion, a rotating stepped portion, and a stirring pin portion, which are installed in sequence from top to bottom.

[0008] Furthermore, the inclination angle of the inclined surface is 1 to 30°.

[0009] Furthermore, the material of the stirring needle part 203 is ceramic material or cemented carbide material.

[0010] Furthermore, the stirring needle part 203 is provided with a side milling plane 20301; the lower end of the stirring needle part 203 is a spherical structure, and the outer surface of the spherical structure is a smooth structure 20302A, a threaded structure 20302B or a milling plane structure 20302C.

[0011] The welding method of the present invention includes the following steps:

[0012] Step 1: Fix the metal sheet 4 on the upper surface of the inclined table 3.

[0013] Step 2: Assemble the rotating part 2 and the non-rotating part 1. There is a gap of 0.1-2 mm between the stirring needle part 203 of the rotating part 2 and the shaft shoulder part 103 of the non-rotating part 1.

[0014] Step 3: The rotating part 2 rotates at a high speed, and the non-rotating part 1 moves statically in a follow-up manner. The two move synchronously along the welding path to form a welded joint.

[0015] Step 4: The welding direction matches the rotation direction of the rotating part 2, so that the advancing side is below the vertical height and the retreating side is above the vertical height. The material flow rate difference between the two sides is used to enhance the material fluidity for material backfilling; the shaft shoulder part 103 compacts and levels the plasticized material around the welded joint to form a high-strength welded joint.

[0016] Furthermore, the welding method is applicable to welding metal sheets with a thickness of 0.5-20 mm.

[0017] The beneficial effects of the present invention are:

[0018] 1. By matching the inclined table surface part of the present invention with the inclined surface of the non-rotating part, the processing table is inclined perpendicular to the welding direction. The height difference between the advancing side and the retreating side of the welding is used to cause a material flow rate difference to improve the material fluidity. The static shaft shoulder structure with a side inclination angle compacts and levels the plasticized material around the welded joint, and improves the surface accuracy and welding quality after welding;

[0019] 2. The material of the stirring needle part of the present invention is ceramic, which enhances the wear resistance and high-temperature stability of the stirring needle part, is easy to process and greatly reduces the production cost;

[0020] 3. The spherical structure of the end face of the stirring needle part of the present invention can be a smooth structure, a threaded structure or a milling plane structure to promote material flow and improve the quality of the welded joint;

[0021] 4. The present invention has a wide applicability and can be extended to various welding forms of multiple materials. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the working process of the welding device of the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of the non-rotating components of the welding device of the present invention;

[0024] Figure 3 It is a schematic diagram of the structure of the rotating components of the welding device of the present invention;

[0025] Figure 4 It is a schematic diagram of the structure of the stirring pin part of the welding device of the present invention.

[0026] In the figure, 1 - non-rotating component, 101 - clamping part, 10101 - positioning and clamping through hole, 102 - stepped part, 10201 - central control structure, 103 - shaft shoulder;

[0027] 2 - rotating component, 201 - rotating clamping part, 20101 - side milling plane, 202 - rotating stepped part, 203 - stirring pin part, 20301 - side milling plane, 20302A - end face of smooth spherical head stirring pin part, 20302B - end face of threaded spherical head stirring pin part, 20302C - end face of milled plane spherical head stirring pin part

[0028] 3: Tilted table surface part

[0029] 4: Metal sheet Specific implementation mode

[0030] Specific implementation mode 1: A friction stir welding device suitable for high melting point metals described in this implementation mode, as Figure 1 shown, includes a non-rotating component 1, a rotating component 2 and a tilted table surface 3; the rotating component 2 is installed inside the non-rotating component 1, the metal sheet is fixed on the tilted table surface 3, and the inclined surface at the lower part of the non-rotating component 1 is used to cooperate with the tilted table surface 3.

[0031] As Figure 2As shown in the figure, the non-rotating component 1 includes a clamping portion 101, a stepped portion 102, and a shaft shoulder portion 103; a hollow structure 10201 with a corresponding shape is provided inside the stepped portion 102 for accommodating the rotating stepped portion 102 of the rotating component 2. It is a hollow structure, and a clamping portion 101 is provided at its upper end for connecting to the non-rotating stator portion of the spindle of machining equipment including but not limited to friction stir welding machines, CNC milling machines, and CNC machining centers; a plurality of through holes 10101 are evenly distributed along the circumferential direction on the clamping portion 101 for positioning and clamping; a shaft shoulder portion 103 is provided at the lower part, and an inclined surface matching the inclined table surface 3 is provided on the bottom surface of the shaft shoulder portion 103; the inclination angle of the inclined table surface 3 is 1-30°. The inclination angle is used to cooperate with the inclined bottom surface of the shaft shoulder portion 103 to compact and level the materials around the weld where the stirring needle portion of the rotating component is thermoplastified, forming a dense and flat welded joint;

[0032] As Figure 3 shown in the figure, the rotating component 2 is installed inside the stepped portion 102. The rotating component 2 includes a rotating clamping portion 201, a rotating stepped portion 202, and a stirring needle portion 203, and the rotating clamping portion 201, the rotating stepped portion 202, and the stirring needle portion 203 are installed in sequence from top to bottom. The rotating clamping portion 201 is used to connect to the rotating spindle rotor portion of machining equipment including but not limited to friction stir welding machines, CNC milling machines, and CNC machining centers, and a side milling plane 20101 is provided thereon for side fixing and clamping; the rotating stepped portion 202 is a cylindrical structure, and the rotating stepped portion 202 and the portion 203 are connected in a split manner.

[0033] As Figure 4 shown in the figure, the stirring needle portion 203 is provided with a side milling plane 20301 for side fixing and clamping; the lower end of the stirring needle portion 203 is a spherical structure, and different structures can be provided on the outer surface of its spherical structure to promote material flow, such as a smooth structure 20302A, a threaded structure 20302B, or a milling plane structure 20302C, to improve the quality of the welded joint.

[0034] Preferably, the material of the stirring needle portion 203 is a ceramic material or a cemented carbide material, etc., which enhances the wear resistance and high-temperature stability of the stirring needle portion 203, is easy to process, and greatly reduces the production cost;

[0035] Preferably, there is a gap of 0.1-2 mm between the stirring needle portion 203 of the rotating component and the shaft shoulder portion 103 of the non-rotating component 1. This avoids friction between the stirring needle portion 203 and the shaft shoulder portion 103 and causes tool wear.

[0036] Preferably, there is an inclination angle of 0-5° between the axis of the rotating component 2 and the non-rotating component 1 along the welding direction and the normal line of the metal sheet surface. Increasing the inclination angle enhances the forging effect of the shaft shoulder portion 103 on the metal sheet and improves the welding quality.

[0037] Embodiment 2: A friction stir welding method applicable to high melting point metals, and its welding process is as follows:

[0038] Fix the metal sheet 4 on the inclined table component 3 using a tooling fixture, and the inclined table component has an inclination angle of 1 to 30°.

[0039] The rotating component 2 rotates at a high speed, and the non-rotating component 1 moves statically in a follow-up manner. The two move synchronously along the welding path to form a welded joint.

[0040] The welding direction matches the rotation direction of the rotating component 2, so that the advancing side is below the vertical height and the retreating side is above the vertical height. Utilize the flow velocity difference between the two sides to enhance the material fluidity, which is conducive to material backfilling. The shaft shoulder 103 compacts and levels the plasticized material around the welded joint to form a high-strength welded joint.

[0041] The welding method described in this embodiment is applicable to the welding of metal sheets with a thickness of 0.5 to 20 mm.

[0042] The welding device and method of the present invention can be used for the welding form of high melting point metals such as steel and titanium, and can also be used for the lap joint form of low melting point metals such as aluminum and steel with high melting point metals.

[0043] Example 1

[0044] Select 304 stainless steel with a thickness of 5 mm as the metal plate to be welded. The inclination angle of the inclined table 3 is 5°. The welding joint form is butt joint, and the metal plate 4 is clamped to the inclined table 3. The structure of the stirring pin part 203 of the rotating part 2 is a smooth ball head structure with a diameter of 16 mm, and the material is silicon carbide ceramic. The inner diameter of the shaft shoulder part 103 of the non-rotating part 1 is 17 mm, and the outer diameter is 25 mm. The shaft shoulder part 103 has a side inclination angle of 5° to cooperate with the inclined table part 3. Connect the clamping part 201 of the rotating part 2 to the rotating main shaft rotor part of the friction stir welding machine, and connect the clamping part 101 of the non-rotating part to the non-rotating main shaft stator part of the friction stir welding machine. Adjust the assembly height so that the lower end face of the stirring pin part 203 is 4 mm higher than the position along the center line of the shaft shoulder part 103. Set the initial position of the stirring pin part 203, which is 100 mm directly above the butt joint surface of the metal plate. Set the rotation direction of the rotating part 2 and its traveling direction with the non-rotating part 1. The rotation direction is counterclockwise, and the traveling direction is along the butt joint surface, so that the vertical height on the forward side of the rotating part is lower and the vertical height on the backward side is higher. Set the sinking speed of the stirring pin part 203. It sinks to 1 mm directly above the butt joint surface of the metal plate at a speed of 500 mm / min and sinks to 4.2 mm directly below the butt joint surface of the metal plate at a speed of 1 mm / min. At this time, the shaft shoulder part 103 is pressed into the stainless steel plate by 0.2 mm, which can effectively compact the welded plate and improve the surface accuracy after welding. The pre-welding residence time is set to 10 s, the rotation speed is 300 rpm, and the traveling speed is 50 mm / min. The welding distance is set to 200 mm. The post-welding residence time is set to 2 s, and then the stirring pin part 203 is lifted, and the lifting speed is set to 10 mm / min. Start the friction stir welding machine and perform welding according to the above set data. High-quality welding of 5-mm-thick 304 stainless steel can be achieved.

[0045] Example 2

[0046] Select 304 stainless steel with a thickness of 3 mm and 6061-T6 aluminum alloy with a thickness of 2 mm as the metal plates to be welded. The inclination angle of the inclined table 3 is 7°. The welding joint form is lap joint, and the metal plate 4 is clamped to the inclined table 3. The structure of the stirring pin part 203 of the rotating part 2 is a smooth ball head structure with a diameter of 14 mm, and the material is silicon carbide ceramic. The inner diameter of the shaft shoulder part 103 of the non-rotating part 1 is 15 mm, and the outer diameter is 24 mm. The shaft shoulder part 103 has a side inclination angle, and the inclination angle is 7° to cooperate with the inclined table 3. Connect the clamping part 201 of the rotating part 2 to the rotating spindle rotor part of the friction stir welding machine, and connect the clamping part 101 of the non-rotating part 1 to the non-rotating spindle stator part of the friction stir welding machine. Adjust the assembly height so that the lower end face of the stirring pin part 203 is 2.5 mm higher than the position along the center line of the shaft shoulder part. Set the initial position of the stirring pin part 203, which is 100 mm directly above the butt joint surface of the metal plates. Set the rotation direction of the rotating part 2 and its traveling direction with respect to the non-rotating part 1. The rotation direction is counterclockwise, and the traveling direction is along the butt joint surface, so that the vertical height on the advancing side of the rotating part 2 is lower and the vertical height on the retreating side is higher. Set the sinking speed of the stirring pin part 203. Sink to 1 mm directly above the butt joint surface of the metal plates at a speed of 500 mm / min, and sink to 2.7 mm directly below the butt joint surface of the metal plates at a speed of 5 mm / min. At this time, the shaft shoulder part 103 is pressed into the aluminum alloy plate by 0.2 mm, which can effectively compact the welded plates and improve the surface accuracy after welding. The pre-welding residence time is set to 10 s, the rotation speed is 500 rpm, and the traveling speed is 100 mm / min. The welding distance is set to 200 mm. The post-welding residence time is set to 2 s, and then the stirring pin part 203 is lifted, and the lifting speed is set to 10 mm / min. Start the friction stir welding machine and perform welding according to the above set data. High-quality welding of 5-mm-thick 304 stainless steel can be achieved.

[0047] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to be equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the technical solution content of the present invention, and based on the technical essence of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A friction stir welding device applicable to high melting point metals, characterized in that, The welding device includes a non-rotating part (1), a rotating part (2) and an inclined table (3). The non-rotating part (1) includes a clamping part (101), a stepped part (102) and a shoulder part (103). The stepped part (102) is a hollow structure, with a clamping part (101) provided at its upper end and a shoulder part (103) provided at its lower end. The bottom end of the shoulder part (103) is provided with an inclined surface that cooperates with the inclined table (3). The rotating part (2) is installed inside the stepped part (102) of the non-rotating part (1).

2. The friction stir welding device for high melting point metals according to claim 1, wherein: The rotating part (2) includes a rotating clamping part (201), a rotating stepped part (202) and a stirring pin part (203). The rotating clamping part (201), the rotating stepped part (202) and the stirring pin part (203) are installed in sequence from top to bottom.

3. The friction stir welding device applicable to high melting point metals according to claim 1, characterized in that: The inclination angle of the inclined table (3) is 1 to 30°, and the inclination angle of the inclined surface at the bottom end of the shoulder part (103) is the same as the inclination angle of the inclined table (3).

4. The friction stir welding device for high melting point metals according to claim 2, characterized in that: The material of the stirring pin part (203) is a ceramic material or a cemented carbide material.

5. The friction stir welding device applicable to high melting point metals according to claim 1, wherein: The stirring pin part (203) is provided with a side milling plane (20301); the lower end of the stirring pin part (203) is a spherical structure.

6. A welding method for a friction stir welding device applicable to high melting point metals according to any one of claims 1-5, characterized in that, The welding method includes the following steps: Step 1: Fix the metal sheet (4) on the upper surface of the inclined table 3. Step 2: Assemble the rotating part (2) and the non-rotating part (1). There is a gap of 0.1 to 2 mm between the stirring pin part (203) of the rotating part (2) and the shoulder part (103) of the non-rotating part (1). Step 3: The rotating part (2) rotates at a high speed, and the non-rotating part (1) moves statically in a follow-up manner. The two move synchronously along the welding path to form a welding joint. Step 4: The welding direction matches the rotation direction of the rotating part (2), so that the advancing side is below the vertical height and the retreating side is above the vertical height. Utilize the flow velocity difference of the materials on both sides to enhance the material fluidity for material backfilling. The shoulder part (103) compacts and levels the plasticized material around the welding joint to form a welding joint.

7. The welding method of a friction stir welding device applicable to high melting point metals according to claim 6, characterized in that, The welding method is applicable to the welding of metal sheets with a thickness of 0.5 to 20 mm.

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