A device and method for stirring friction stir welding and spot welding of porous materials

Abstract

A stirring device and method for friction stir welding spot welding of porous materials, characterized in that the stirring device includes a stirring needle consumable layer, a stirring needle matrix and an outer shoulder, the stirring needle consumable layer and the stirring needle matrix cooperate to form a stirring needle, the stirring needle is installed in the outer shoulder, the outer shoulder is fixed on one end of the adjustment platform, the stirring needle is rotatably mounted on the adjustment platform through a rotary bearing, the stirring needle fixed end equipped with a stirring needle rotation drive device is also mounted on the adjustment platform, the other end of the adjustment platform is sleeved on the transmission shaft through a sliding shaft, the lower end of the transmission shaft is fixed on the workbench, the upper end of the transmission shaft is mounted on a cylinder, the cylinder rod of the cylinder is connected to the adjustment platform, and the cylinder rod drives the adjustment platform to move up and down. The present invention fills the exit concave hole of the friction stir welding spot welding joint through the consumption relationship of the stirring needle consumable layer and the stirring needle, and the welded spot weld is smooth.

Description

Technical Field

[0001] The present invention belongs to the technical field of friction stir welding, in particular to a friction spot welding technology for porous materials, specifically to a friction stir welding spot welding stirring device and method for porous materials in the field of friction stir welding. Background Art

[0002] Friction stir welding is a further development based on conventional friction stir welding. While the stirring head is rotating, a forging force is applied to the stirring head to press it into the sheet. Under the action of pressure, the stirring head rubs against the sheet, causing the sheet to plasticize. A weld is formed under the action of the stirring needle. After a period of time, the stirring head is lifted to form a complete friction stir welding spot joint.

[0003] Although this technology has many significant advantages, it still has the following shortcomings in actual application operations: When performing friction stir spot welding on porous materials, due to the insufficient density of the welding base material, the weld joint will collapse during the process of pressing down the shaft shoulder and the stirring needle. Insufficient material is required for joint formation, resulting in the mechanical properties of the joint not meeting the requirements. At the same time, after welding, the withdrawal of the stirring needle in friction stir spot welding will leave a typical exit hole in the center of the weld. At the same time, due to the collapse of the welding base material, a groove will be formed, which often forms weak connection surfaces, holes and other welding defects in the groove, resulting in poor welding quality stability and low joint strength.

[0004] In order to solve these problems, for example, as described in patent CN214684724U, there is an additive channel in the stirring head structure, and materials can be added through the additive channel through a specific additive device. At the same time, a positioning ring structure is added to reduce the contact area between the tool handle and the stirring head, thereby reducing heat transfer. However, adding materials through the additive channel may cause the additive channel to be blocked due to uneven plasticization of the material, and it cannot work stably. Patent CN 105108361 A describes a keyhole-free stir friction welding spot welding device, which uses an ultrasonic exciter to assist. The ultrasonic exciter emits ultrasonic waves to the plate to be welded to plastically soften the metal material. At the same time, the separate stirring sleeve and stirring needle can solve the problem of keyholes, solve the problem of insufficient input in the stir friction spot welding process, and solve the problem of insufficient material flow, and it is not easy to form holes and other defects. However, this method cannot solve the problem of collapse of the parent material and cannot be applied to stir friction spot welding of porous materials.

[0005] Regarding the problem of how to achieve material addition during the friction stir welding process of porous materials and thus compensate for the collapse of the friction stir welding process of porous materials, this patent proposes a new structure and method for the friction stir welding stirring head of porous materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies that occur in the above-mentioned stir friction welding spot welding process of porous materials, and propose a stir friction welding spot welding stirring device and method for porous materials to solve the problems of insufficient joint forming material causing collapse of the base material and inability to form the joint during the stir friction welding spot welding of porous materials.

[0007] One of the technical solutions of the present invention is:

[0008] A stirring head for friction stir welding and spot welding of porous materials, comprising: a stirring needle consumable layer, a stirring needle matrix, an outer shoulder, a cylinder, a transmission shaft, an adjustment platform, a workbench, etc. The stirring needle consumable layer matches the stirring needle matrix to form a stirring needle, and the stirring needle is connected to the outer shoulder. The stirring needle matrix is ​​directly connected to the outer shoulder, and before the start of friction stir welding, the adjustment platform is controlled by the cylinder to match the outer shoulder with the welding plate; during the friction stir welding process, the stirring needle enters the base material downward along the main shaft, frictionally stirs the base material, and plasticizes the base material and the stirring needle consumable layer. The stirring needle consumable layer and the stirring head matrix can slide against each other, and the stirring needle consumable layer rotates with the main shaft. During the friction stir welding process, the outer shoulder and the surface of the welding plate maintain a constant height after being fitted, and the stirring needle consumable layer moves downward with the main shaft into the welding material. The stirring needle consumable layer rubs against the porous material to plasticize the stirring needle consumable layer material. While generating heat, the material of the stirring needle consumable layer separates from the stirring needle and is transferred to the friction stir welding joint and the stirring head matching hole, solving the problem of base material collapse caused by insufficient material density of the porous material during the friction stir welding process.

[0009] The second technical solution of the present invention is:

[0010] A stir friction welding spot welding stirring device for porous materials, characterized in that it includes a stirring needle consumable layer 8, a stirring needle matrix 7 and an outer shoulder 6, the stirring needle consumable layer 8 and the stirring needle matrix 7 cooperate to form a stirring needle, the stirring needle is installed in the outer shoulder 6, the outer shoulder 6 is fixed to one end of the adjusting platform 4 by a connecting bolt 11, the stirring needle is rotatably installed on the adjusting platform 4 through a rotary bearing 9, and the stirring needle fixed end 10 equipped with a stirring needle rotation drive device is also installed on the adjusting platform 4, the other end of the adjusting platform 4 is connected to the transmission shaft 2 and installed in the slide rail 12, the transmission shaft 2 is connected to the cylinder shaft 13, the cylinder 1 is installed at the upper end of the slide rail 12, and the lower end of the slide rail 12 is fixed on the workbench 5, the cylinder shaft 13 of the cylinder 1 drives the transmission shaft 2 to move up and down, the transmission shaft 2 drives the adjusting platform 4 to move up and down along the slide rail 12, the adjusting platform 4 drives the outer shoulder 6 and the stirring needle to move up and down, compacting the spot welding position, and the stirring needle is pressed down along the outer shoulder while rotating. The stirring needle consumable layer 8 is consumed and fills the welding cavity during the stirring process.

[0011] The third technical solution of the present invention is:

[0012] A method for stir friction welding spot welding of porous materials is characterized in that: first, the friction heat generated by the stirring needle consumable layer and the processed base material causes the material of the stirring needle consumable layer to plasticize and fill the gaps generated by the collapse of the porous material during the stir friction welding spot welding process; second, the stirring needle matrix moves up and down during the stir friction welding spot welding process so that the melted material of the stirring needle consumable layer enters the stirring area, and when the stirring needle matrix exits, the consumable layer stays in the welding plate, thereby eliminating the exit concave hole left by the stir friction welding spot welding.

[0013] The specific steps are as follows:

[0014] First, the material used for the consumable layer of the porous material stirring head and the thickness of the consumable layer are determined according to the material of the base material, and the consumable layer is processed in coordination with the stirring needle base.

[0015] Second, after the base material and the stirring needle are installed, start the cylinder, control the adjustment platform to be driven by the cylinder, and adjust the welding plate installed on the workbench to match the outer shoulder;

[0016] Third, after the welding plate and the outer shoulder are installed, the spindle rotates and presses down, the outer shoulder presses the base material, and the consumable layer of the stirring needle is inserted into the base material. As the stirring needle body rotates continuously, under the action of pressure and the rotation of the consumable layer of the stirring needle, friction heat is generated between the workpiece and the consumable layer of the stirring head, and the consumable layer of the stirring head will continue to be pressed into the workpiece.

[0017] Fourth, after the needle consumable layer has completely entered the workpiece, maintain the pressure of the stirring head to connect the outer shoulder with the workpiece, and keep rotating for a while while the softened material is squeezed into the matching hole. At this time, the needle consumable layer will fall off from the stirring needle mother body due to the influence of temperature and deformation.

[0018] Fifth, after the connection is completed, when the stirring needle matrix is ​​slowly withdrawn from the workpiece, the stirring needle consumable layer and the welding base material fill the keyhole left by the stirring needle matrix. By consuming the stirring needle consumable layer, the stir friction weld joint is formed, forming a smooth weld joint.

[0019] Specifically: when the welding base material is a porous material, the weld cannot be formed by general stir friction spot welding. Through step three, the material on the consumption layer of the stirring needle is plasticized by the friction heat generated by the friction with the base material, and is brought into the stirring zone by the stirring action of the stirring needle to complete the material addition, thereby overcoming the problem that the welding joint of the porous material cannot be formed due to insufficient material during the stir friction spot welding process. At the same time, due to the cooperation of the stirring needle, the material in the cooperation hole of the stirring needle is squeezed during the withdrawal of the stirring needle, filling the exit concave hole and solving the collapse problem of the base material.

[0020] The beneficial effects of the present invention are:

[0021] (1) The consumption of the stirring needle consumable layer and the cooperation relationship of the stirring needle fill the exit concave hole of the stir friction welding spot welding joint, and the welded spot weld is smooth.

[0022] (2) A porous material spot welding stirring head structure is provided, which comprises a stirring head matrix, a stirring needle consumable layer, and an outer shaft shoulder. The stirring needle matrix and the stirring needle consumable layer cooperate with each other, and the stirring needle matrix and the stirring needle consumable layer rub against the processed base material to achieve additive stir friction welding, thereby solving the problem of base material collapse that may occur in stir friction welding of porous materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The utility model relates to a structure and an installation device of a stirring head for friction stir welding and spot welding of porous materials.

[0024] Figure 2 、 3 Schematic diagram of the specific dimensions of the stirring needles corresponding to Example 1 and Example 2.

[0025] Figure 4 The invention relates to a second structure and installation device of a stirring head for friction stir welding spot welding of porous materials.

[0026] Figure 5 This is a schematic diagram of the thread matching between the stirring needle mother body and the stirring needle consumable layer.

[0027] Figure 6 Schematic diagram of the stirring needle mother body.

[0028] Figure 7 Schematic diagram of the stirring needle consumption layer.

[0029] Figure 8 Front view of the spindle tool holder.

[0030] Figure 9 This is a schematic diagram of the installation of the external shoulder and the adjustment platform.

[0031] In the figure, 1 is the cylinder, 2 is the transmission shaft, 3 is the sliding bearing, 4 is the adjustment platform, 5 is the workbench, 6 is the outer shoulder, 7 is the stirring needle mother body, 8 is the stirring needle consumable layer, 9 is the rotary bearing, and 10 is the stirring needle fixed end. DETAILED DESCRIPTION

[0032] The present invention will now be described in more detail with reference to the accompanying drawings and examples. The accompanying drawings are simplified schematic diagrams that illustrate only a basic structure of the present invention. Therefore, they only show structures relevant to the present invention. The description of the examples is intended only to further illustrate the features of the present invention and is not intended to limit the claims of the present invention.

[0033] Example 1.

[0034] like Figure 1 shown.

[0035] A porous material friction stir welding spot welding stirring head, comprising: a stirring needle consumable layer 8, a stirring needle matrix 7 and an outer shaft shoulder 6, such as Figure 1 As shown, the needle consumable layer 8 and the needle matrix 7 cooperate to form a needle. The needle is installed in the outer shoulder 6, and the outer shoulder 6 is fixed on one end of the adjustment platform 4. The needle is rotatably mounted on the adjustment platform 4 through a rotary bearing 9. The needle fixed end 10 equipped with a needle rotation drive device is also mounted on the adjustment platform 4. The other end of the adjustment platform 4 is sleeved on the transmission shaft 2 through a sliding shaft 3. The lower end of the transmission shaft 2 is fixed on the workbench 5. The upper end of the transmission shaft 2 is installed with a cylinder 1. The cylinder rod of the cylinder 1 is connected to the adjustment platform 4, and the cylinder rod drives the adjustment platform up and down. Among them, the needle matrix is ​​directly connected to the outer shoulder. Before the start of friction stir welding, the adjustment platform is controlled by the cylinder to make the outer shoulder and the welding plate match well. During the friction stir welding spot welding process, the needle moves downward into the base material along with the main shaft, frictionally stirring the base material, so that the base material and the needle consumable layer are plasticized. The needle consumable layer and the stirring head matrix can slide with each other, and the needle consumable layer rotates with the main shaft. During the friction stir welding process, the outer shoulder and the surface of the welding plate maintain a constant height after being fitted, and the stirring needle consumable layer moves downward with the main shaft into the welding material. The stirring needle consumable layer rubs against the porous material to plasticize the stirring needle consumable layer material. While generating heat, the material of the stirring needle consumable layer separates from the stirring needle and is transferred to the friction stir welding joint and the stirring head matching hole, solving the problem of base material collapse caused by insufficient material density of the porous material during the friction stir welding process.

[0036] Example 2.

[0037] like Figure 4-9 shown.

[0038] A stir friction welding spot welding stirring device for porous materials, comprising a stirring needle consumable layer 8 ( Figure 7 )、Stirring needle matrix 7( Figure 6 ) and the outer shoulder 6, the stirring needle consumable layer 8 and the stirring needle matrix 7 cooperate to form a stirring needle (such as Figure 5 ), the stirring needle is installed in the outer shoulder 6, and the outer shoulder 6 is fixed to one end of the adjustment platform 4 by a connecting bolt 11 (such as Figure 9 ), the stirring needle is rotatably mounted on one end of the adjustment platform 4 through a rotary bearing 9, and the stirring needle fixed end 10 equipped with a stirring needle rotation drive device is also mounted on the adjustment platform 4 and fixedly connected to the upper end of the stirring needle. The other end of the adjustment platform 4 is connected to the transmission shaft 2 and mounted in the slide rail 12, as shown Figure 4As shown, the transmission shaft 2 is connected to the cylinder shaft 13, the cylinder 1 is installed on the upper end of the slide rail 12, and the lower end of the slide rail 12 is fixed on the workbench 5. The cylinder shaft 13 of the cylinder 1 drives the transmission shaft 2 to move up and down, and the transmission shaft 2 drives the adjustment platform 4 to move up and down along the slide rail 12. The adjustment platform 4 drives the outer shaft shoulder 6 and the stirring needle to move up and down to compact the spot welding position. The stirring needle is pressed down along the outer shaft shoulder while rotating, and the stirring needle consumption layer 8 is consumed and fills the welding void during the stirring process.

[0039] Example 3.

[0040] A method for friction stir welding of porous materials, comprising the following steps:

[0041] First, the material used for the consumable layer of the porous material stirring head and the thickness of the consumable layer are determined according to the material of the base material, and the consumable layer is processed in coordination with the stirring needle base.

[0042] Second, after the base material and the stirring needle are installed, start the cylinder, control the adjustment platform to be driven by the cylinder, and adjust the welding plate installed on the workbench to match the outer shoulder;

[0043] Third, after the welding plate and the outer shoulder are installed, the spindle rotates and presses down, the outer shoulder presses the base material, and the consumable layer of the stirring needle is inserted into the base material. As the stirring needle body rotates continuously, under the action of pressure and the rotation of the consumable layer of the stirring needle, friction heat is generated between the workpiece and the consumable layer of the stirring head, and the consumable layer of the stirring head will continue to be pressed into the workpiece.

[0044] Fourth, after the needle consumable layer has completely entered the workpiece, maintain the pressure of the stirring head to connect the outer shoulder with the workpiece, and keep rotating for a while while the softened material is squeezed into the matching hole. At this time, the needle consumable layer will fall off from the stirring needle mother body due to the influence of temperature and deformation.

[0045] Fifth, after the connection is completed, when the stirring needle matrix is ​​slowly withdrawn from the workpiece, the stirring needle consumable layer and the welding base material fill the keyhole left by the stirring needle matrix. By consuming the stirring needle consumable layer, the stir friction weld joint is formed, forming a smooth weld joint.

[0046] Specifically: when the welding base material is a porous material, the weld cannot be formed by general stir friction spot welding. Through step three, the material on the consumption layer of the stirring needle is plasticized by the friction heat generated by the friction with the base material, and is brought into the stirring zone by the stirring action of the stirring needle to complete the material addition, thereby overcoming the problem that the welding joint of the porous material cannot be formed due to insufficient material during the stir friction spot welding process. At the same time, due to the cooperation of the stirring needle, the material in the cooperation hole of the stirring needle is squeezed during the withdrawal of the stirring needle, filling the exit concave hole and solving the collapse problem of the base material.

[0047] Example 1.

[0048] like Figure 2 As shown, an 8mm thick foam aluminum plate is selected for welding. It is known that the welding base material is foam aluminum, and a stirring needle consumable layer made of aluminum can be selected. The installation of the stirring head is shown in Figure 2. The welding inclination angle is 2.5°, and the stirring needle consumable layer rotates counterclockwise. The thickness of the stirring needle consumable layer is 2mm, and the length of the stirring needle matrix and the stirring needle consumable layer is 7.5mm. The stirring head speed during welding is 400rpm. First, the stirring needle matrix is ​​processed and matched. Second, after the base material and the outer shoulder are installed, the main shaft rotates and presses down, and the stirring consumable layer is inserted into the base material. At the same time, the stirring needle consumable layer gradually melts and detaches. Under the action of pressure and the rotation of the stirring needle, the foam aluminum plate and the stirring needle consumable layer generate frictional heat, and the stirring needle consumable layer will continue to be pressed into the workpiece. Third, after the stirring needle consumable layer completely enters the foam aluminum plate, maintain the stirring head pressure to connect the stirring needle consumable layer to the foam aluminum plate, and the stirring needle consumable layer is completely separated from the stirring needle. Keep rotating for a period of time until the material is completely plasticized. Fourth, after the connection is completed, the stirring needle matrix is ​​slowly withdrawn from the foam aluminum plate, and the stir friction welding joint is formed by consuming the stirring needle consumption layer, and the withdrawal concave hole is filled at the same time.

[0049] Example 2.

[0050] like Figure 3 As shown, a 4mm thick porous foam brass plate is selected for welding. It is known that the welding base material is porous foam brass, and a stirring needle consumable layer made of aluminum can be selected. The installation of the stirring head is shown in Figure 3. The welding inclination angle is 2.5°, and the stirring needle consumable layer is rotated counterclockwise. The thickness of the stirring needle consumable layer is 2mm, and the length of the stirring needle matrix and the stirring needle consumable layer is 3.8mm. The stirring head speed during welding is 600rpm. First, the stirring needle matrix is ​​processed and matched. Second, after the base material and the outer shoulder are installed, the main shaft rotates and presses down, the stirring consumable layer is inserted into the base material, and the stirring needle consumable layer gradually melts and detaches. Under the action of pressure and the rotation of the stirring needle, the porous foam brass plate and the stirring needle consumable layer generate frictional heat, and the stirring needle consumable layer will continue to be pressed into the workpiece. Third, after the stirring needle consumable layer completely enters the porous foam brass plate, the stirring head pressure is maintained to connect the stirring needle consumable layer to the porous foam brass plate, and the stirring needle consumable layer is completely separated from the stirring needle. Keep rotating for a period of time until the material is completely plasticized. Fourth, after the connection is completed, the stirring pin matrix is ​​slowly withdrawn from the porous foam brass plate, and the friction stir welding joint is formed by consuming the stirring pin consumption layer, and the withdrawal concave hole is filled at the same time.

[0051] The above is only the second implementation method of this patent. It should be pointed out that: based on the above description, relevant personnel can make several improvements and modifications without departing from the principles of this patent. These improvements and modifications should also be regarded as the scope of protection of this patent.

[0052] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

Claims

1. A device for friction stir welding and spot welding of porous materials, characterized by: It comprises a stirring needle consumable layer (8), a stirring needle matrix (7) and an outer shaft shoulder (6), wherein the stirring needle consumable layer (8) cooperates with the stirring needle matrix (7) to form a stirring needle, the stirring needle is installed in the outer shaft shoulder (6), the outer shaft shoulder (6) is fixed on one end of the adjustment platform (4), the stirring needle is rotatably installed on the adjustment platform (4) through a rotary bearing (9), the stirring needle fixed end (10) equipped with a stirring needle rotation drive device is also installed on the adjustment platform (4), the other end of the adjustment platform (4) is sleeved on the transmission shaft (2) through a sliding shaft sleeve (3), the lower end of the transmission shaft (2) is fixed on the workbench (5), the upper end of the transmission shaft (2) is equipped with a cylinder (1), the cylinder rod of the cylinder (1) is connected to the adjustment platform (4), and the cylinder rod drives the adjustment platform to move up and down; the material of the stirring needle consumable layer should be selected from aluminum or magnesium, which has a lower melting point than the welding base material and is not easy to form intermetallic compounds with the base material; the stirring needle consumable layer (8) is consumed and fills the welding cavity during the stirring process.

2. The spot welding stirring device according to claim 1, characterized in that: The stirring needle consumable layer and the stirring needle matrix are matched through processing. Different materials, thicknesses and lengths of the stirring head consumable layer can be selected according to the matrix material and thickness of the stir friction welding spot weld.

3. The spot welding stirring device according to claim 1, characterized in that: The thickness of the stirring head consumable layer is 0.01mm-50mm to meet the requirements of different types of welding. The length of the stirring needle matrix and the stirring needle consumable layer is slightly smaller than the thickness of the welding plate to meet the welding requirements.

4. A device for friction stir welding and spot welding of porous materials, characterized in that: It includes a stirring needle consumable layer (8), a stirring needle matrix (7) and an outer shaft shoulder (6), wherein the stirring needle consumable layer (8) and the stirring needle matrix (7) cooperate to form a stirring needle, the stirring needle is installed in the outer shaft shoulder (6), the outer shaft shoulder (6) is fixed to one end of the adjustment platform (4) through a connecting bolt (11), the stirring needle is rotatably installed on the adjustment platform (4) through a rotary bearing (9), the stirring needle fixed end (10) equipped with a stirring needle rotation drive device is also installed on the adjustment platform (4), the other end of the adjustment platform (4) is connected to the transmission shaft (2) and installed in the slide rail (12), the transmission shaft (2) is connected to the cylinder shaft ( 13), the cylinder (1) is installed at the upper end of the slide rail (12), the lower end of the slide rail (12) is fixed on the workbench (5), the cylinder shaft (13) of the cylinder (1) drives the transmission shaft (2) to move up and down, the transmission shaft (2) drives the adjustment platform (4) to move up and down along the slide rail (12), the adjustment platform (4) drives the outer shaft shoulder (6) and the stirring needle to move up and down, compacting the spot welding position, and the stirring needle is pressed down along the outer shaft shoulder while rotating. The material of the stirring needle consumable layer should be selected from aluminum or magnesium with a lower melting point than the welding base material and not easy to form intermetallic compounds with the base material; the stirring needle consumable layer (8) is consumed and fills the welding cavity during the stirring process.

5. A method for friction stir welding of porous materials based on the spot welding stirring device according to claim 1 or 4, characterized in that: First, the friction heat generated by the consumable layer of the stirring needle and the processed base material causes the material of the consumable layer of the stirring needle to plasticize and fill the gaps caused by the collapse of the porous material during the stir friction welding spot welding process; secondly, the stirring needle matrix moves up and down during the stir friction welding spot welding process so that the melted material of the consumable layer of the stirring needle enters the stirring area, and when the stirring needle matrix exits, the consumable layer stays in the welding plate, thereby eliminating the exit concave hole left by the stir friction welding spot welding.

6. The method according to claim 5, characterized in that: The outer shoulder size of the consumable stirring head for friction stir welding of porous materials is 5-100mm, and the diameter of the stirring needle matrix is ​​2-50mm.

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