Underwater magnetic field coupling magnetostrictive backfilling friction spot welding method and device

Abstract

The application discloses an underwater magnetic field coupling magnetostrictive backfill type friction spot welding device, which comprises a stirring needle, a compression ring, welding material, a compression ring chuck, a top end clamp, a top rod, a cap, an electromagnetic transducer, a magnetic conducting ring, a fixed connecting rod and a water tank; the top end clamp is fixed on the compression ring chuck and cooperates with the internal top rod to fix the welding material at the bottom end of the electric spindle; the fixed connecting rod is sequentially sleeved with the electromagnetic transducer and the cap, and the three are concentrically matched and located at the bottom of the welding point center; the magnetic field energy is converted into electric energy and mechanical energy to the welding point through the electromagnetic transducer. The stirring needle is opposite to the surface of the welding material; the welding material is submerged in the pool of the water tank, and the pool water flow in the water tank is adjusted according to the temperature change; the electronic converter is added at the bottom to improve the temperature distribution of the welding point and the material flow; the underwater welding reduces the heat input and the heat affected zone structure area, and ensures the effective implementation of electromagnetic induction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of friction stir welding, in particular to a method and device for underwater magnetic field coupled magnetostrictive backfilling friction spot welding BACKGROUND

[0002] Backfilling friction spot welding is a new type of spot welding method developed by GKSS GmbH on the basis of friction stir welding, which can overcome the problem of spoon hole existing at the end of conventional friction stir spot welding. Since RFSSW is also a solid-state joining technology, it can avoid the defects of fusion welding and reduce the weight of the structure, and therefore is widely used in the fields of aerospace and automobile manufacturing. At present, RFSSW has the potential to replace traditional resistance spot welding, crack and defect repair.

[0003] The welding process is divided into four stages: friction heating, plunging, retraction, and forming. In the friction heating stage, the clamping ring presses and fixes the welding material, while the stirring pin and sleeve continuously rotate at an angular velocity ω on the base material surface to generate heat and soften it. In the plunging stage, the sleeve plunges to a depth PD within a set time, while the stirring pin rises to a height kPD, forming a cavity. Under the constraint of the clamping ring, most of the metal is squeezed into the cavity, forming a storage chamber. In the retraction stage, within a set time, the sleeve and stirring pin move in opposite directions by distances RD and kRD, respectively, squeezing out the material from the storage chamber. In the forming stage, the stirring pin and sleeve rotate and remain on the surface of the upper plate, polishing the weld joint surface to improve its appearance, after which the tools are removed. Currently, the ultimate shear strength of backfill-type friction stir welded joints is mainly limited by hook defects and coarse microstructure in the heat-affected zone. Due to the lower temperature and harder material of the lower plate aluminum alloy, the surface oxides break and are squeezed onto the upper plate, forming a weak hook-shaped metallurgical bond, which is the source of joint crack propagation. Furthermore, the welding thermal cycle creates a region inside the joint with a hardness lower than that of the base material, known as the heat-affected zone (HAZ). This is particularly true for aluminum alloys, where the HAZ's maximum strength is approximately 80% of the base material, significantly reducing the joint's mechanical properties. Currently, patent CN113857649A places a circumferential excitation coil at the bottom of the base plate. Under the control of a magnetic field controller, several high-frequency magnetizing coils are alternately energized with direct current. The energizing sequence is consistent with the rotation direction of the stirring head, and the alternating energizing speed is the same as the stirring head's rotation speed. After the high-frequency magnetizing coils are energized, a magnetic field is generated that passes through the solder; the magnetic field disappears after the power is cut off. Eddy currents are generated inside the solder, improving the temperature distribution of the base plate and generating Ampere force within the solder, strengthening the stirring effect of the stirring head and improving the weld metal's fluidity. However, in this scheme, the excitation coil is inside the base plate. The accumulation of heat in the base plate increases the coil's resistivity, enhancing Joule heating. The iron plate is more likely to reach the Curie point, reducing magnetic conductivity, and over time, the wires are prone to burnout. The electromagnetic force excited by the rotating magnetic field only exerts a rotational force on the solder. While the actual rotational stirring force in friction stir welding is sufficient, the longitudinal force on the solder is relatively small, thus failing to improve the hook morphology. Furthermore, the magnetic field at the bottom of the winding does not guide the formation of a closed loop, resulting in significant magnetic losses. Patent CN101934426B employs an underwater friction stir welding method, utilizing the strong heat absorption of the water medium to alleviate the problem of coarse microstructure in the heat-affected zone, effectively improving the tensile strength of the joint. However, it does not improve longitudinal material flow and even further reduces the temperature gradient difference in the plates, leading to an increase in hook height.

[0004] It can be seen that the following problems exist in the current external field composite backfill type friction stir welding method: (1) the auxiliary magnetic field generates rotating electromagnetic force by rotating magnetic field and cannot enhance the longitudinal flow of the material; (2) the winding is located inside the bottom plate, and long-term heat accumulation causes the resistivity to rise, the core is easy to reach the Curie temperature, the wire is melted, and the electromagnetic induction efficiency is affected; (3) one end of the winding is close to the welding point, and the other end is in an open state, and the magnetic field energy loss is serious; (4) the problem of coarse and softening of the heat affected zone cannot be solved. Therefore, a kind of underwater magnetic field coupling magnetostrictive backfill type friction spot welding method and device is proposed. SUMMARY

[0005] In order to overcome the deficiencies in the prior art, the present application provides a kind of underwater magnetic field coupling magnetostrictive backfill type friction spot welding method and device, relieve heat affected zone organization coarse, improve the organization defect of hook, connection band etc., improve joint form.

[0006] To solve the above technical problems, the present application provides a kind of underwater magnetic field coupling magnetostrictive backfill type friction spot welding device, including stirring needle, compression ring, welding material, compression ring chuck, top clamp, top rod, cap, electromagnetic transducer, magnetic ring, fixed connecting rod and water tank;The top clamp is fixed with compression ring chuck, cooperates with the internal top rod, and the welding material is fixed at the bottom end of the electric spindle. Fixed connecting rod is successively sleeved with electromagnetic transducer and cap, and the three are concentrically matched, located at the bottom of the welding point center, and the magnetic field energy is converted into electric energy and mechanical energy to the welding point by electromagnetic transducer. The stirring needle is opposite to the surface of the welding material;Welding material is submerged in the pool of water tank, and the water flow in the pool of water tank is adjusted according to the temperature change.

[0007] As preferred, the stirring needle, sleeve and compression ring are fixed at the bottom end of the retractable electric spindle, and the three are concentrically matched. The sleeve and the stirring needle can rotate and move axially. The pool of the water tank is slightly submerged at the bottom of the compression ring.

[0008] As preferred, the cap is made of high-temperature-resistant, wear-resistant, high-hardness and low-permeability material, such as austenitic stainless steel, titanium alloy and copper alloy, and a heat-insulating wear-resistant coating, such as aerogel, is placed on the surface. The outer diameter of the top end of the cap is greater than the outer diameter of the sleeve and less than the outer diameter of the compression ring. The outer diameter of the bottom end is consistent with the inner diameter of the coil. The inner diameter of the blind hole at the bottom end is consistent with the outer diameter of the iron core built-in the electromagnetic transducer and the top of the fixed connecting rod.

[0009] As preferred, the electromagnetic transducer includes upper coil, iron core, lower coil and magnetostrictive ring. The upper coil and the lower coil winding are wound in the same direction. The magnetostrictive ring is made of super magnetostrictive material. The outer diameter of the magnetostrictive ring is consistent with the outer diameter of the bottom end of the cap. The upper and lower coils are separately powered or synchronously powered according to different welding stages. The coil is coated with waterproof paint on the outside, and is wrapped with corrosion-resistant material on the outside. Alternatively, a water-carrying copper pipe can be used in the case of no pool.

[0010] As preferred, the electromagnetic transducer, the cap, the magnetic ring are integrally installed on the upper end of the fixed connecting rod, the bottom end surface of the electromagnetic transducer contacts the stepped surface of the fixed connecting rod, the cap is fixed on the boss of the fixed connecting rod, the boss of the fixed connecting rod wraps the electromagnetic transducer, the magnetic ring wraps the whole electromagnetic transducer, the outer diameter of the magnetic ring is adjusted according to the characteristics of the welding plate, the magnetic guide line is horizontally distributed at the connection interface of the traction welding point area, and the vertical electric potential is formed. The upper coil wraps the cap, the cap is internally provided with an iron core, the lower coil wraps the magnetostrictive ring, the boss of the fixed connecting rod penetrates through the magnetostrictive ring and the blind hole at the bottom of the cap, and the top end of the fixed connecting rod is tightly attached to the bottom end surface of the cap. The center hole of the magnetostrictive ring and the blind hole at the bottom end of the cap are in sliding fit with the top end of the fixed connecting rod, and the magnetic ring and the bottom end surface of the electromagnetic transducer are tightly attached to the stepped end surface of the fixed connecting rod.

[0011] As preferred, the electromagnetic transducer can be applied in the friction stir welding process and the friction stir additive process, the variable resonance condition is automatically adjusted by adjusting the current frequency with the change of the height of the additive component, and the peak intensity of excitation is kept unchanged with the change of the height of the additive.

[0012] As preferred, the pressing ring and the pad rod are fixed on the upper and lower end surfaces of the welding material, the two side end surfaces of the welding material are fixed by the side step of the top clamp and the top rod; the top clamp is fixed on the pressing ring clamp through the side wall threaded hole, the center through hole is concentric with the pressing ring chuck, and the anti-rotation groove is cut through the fixed nut of the pressing ring to avoid the rotation of the clamp, and the side step is tightly attached to one end of the welding material; the top rod penetrates through the side through hole of the top clamp, the top rod is in sliding fit with the measuring through hole, and the top rod is matched with the spring to fix the welding material, or the top rod is in threaded fit to fix the welding material, and the two top rods act on the two welding material overlapping areas with a width of about 3 / 4.

[0013] As preferred, the pool is provided with an inlet flow switch and an outlet flow switch, and is provided with a limiting sensor and a temperature measuring sensor located at the bottom horizontal surface of the sleeve.

[0014] The welding process adjusting electromagnetic coupling magnetostrictive method also provides a welding tool.

[0015] The welding material is fixed on the top clamp, and the welding material is prevented from rotating in the welding process;

[0016] The sleeve is lowered to the surface of the backing plate to start the preheating stage, at this time, the upper coil is turned on to only excite the Joule heat;

[0017] The lower and the retraction stages are simultaneously connected with the upper coil and the lower coil, and the Joule heat effect, the electromagnetic force and the ultrasonic vibration are excited;

[0018] In the forming stage, the lower coil is turned on to only excite the ultrasonic vibration.

[0019] The application also provides a method for controlling the flow of a water tank based on temperature, which adopts the welding tool as above, and comprises the following steps:

[0020] The welding material is fixed on the top clamp to ensure that it does not rotate in the actual welding process, and the introduced water is always at room temperature;

[0021] The limiting sensor on the horizontal plane of the welding material ensures that the water surface of the water tank is always higher than the welding material, and when the water surface is lower than the travel sensor, only the water inlet switch is turned on, and in other cases, the water inlet switch and the water outlet switch are in the same state, and the water flow switch is divided into 8 grades;

[0022] The temperature of the water tank is measured as Y°, and when X°≥Y°, the upper coil is powered on, and the water flow switch is closed, and when X°<Y°, the preheating stage is started, and the water flow switch is opened;

[0023] During the lower insertion and retraction processes, the water flow switch adjusts the number of grades according to the temperature change, and the number of grades=(Y-X) / 10, and when it is less than zero, the water flow switch is closed;

[0024] The water flow switch is closed at the end of the welding.

[0025] Advantages: Compared with the prior art, the application has the following advantages:

[0026] (1) For the concentrated heat input of welding, the first coil is added at the bottom to improve the temperature distribution of the welding material;

[0027] (2) The coil is segmented, and a magnetostrictive ring is added to the internal structure of the lower coil to reduce the energy loss of electromagnetic auxiliary bottom and improve the energy utilization efficiency;

[0028] (3) Compared with piezoelectric ceramics, high-voltage excitation response is required, the circuit is easy to break down, the danger is high, and the vibration amplitude cannot be changed in real time. However, the super-magnetostrictive material can be driven to respond at low voltage and can work continuously with high response speed for a long time, and the alternating current frequency can be automatically adjusted to the variable vibration condition;

[0029] (4) For the problem of insufficient longitudinal flow of the material, longitudinal electromagnetic stirring force and ultrasonic vibration are added to enhance the longitudinal mixing degree of the material;

[0030] (5) For the problems of poor electromagnetic induction effect and coarse heat-affected zone structure caused by temperature rise during the welding process, underwater welding is used to reduce the temperature and reduce the heat-affected zone structure to ensure the effective implementation of electromagnetic induction;

[0031] (6) The conventional backing plate is thick, the auxiliary magnetic field is far away from the weld core, the magnetic field decays seriously, the cap increases the magnetic field accommodation space and can guide the magnetic field to be directly located below the weld point, and the electromagnetic induction effect is increased;

[0032] (7) magnetic field coupling magnetostrictive material excitation energy field, the structure is exquisite, simple, and temperature control is easy to realize. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some schematic diagrams of the welding tool structure and method of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0034] Figure 1 The schematic diagram of the backfilling friction spot welding state provided in the embodiment of the present application is shown in the figure.

[0035] Figure 2 The schematic diagram of the electromagnetic transducer is shown in the figure.

[0036] Figure 3 The schematic diagram of the top clamp is shown in the figure.

[0037] Figure 4 The coil energization circuit diagram is shown in the figure.

[0038] Wherein, 1-stirring needle; 2-sleeve; 3-pressing ring; 4-cap; 5-water tank; 6-welding material; 7-fixed connecting rod; 8-electromagnetic transducer; 9-magnetic ring; 10-top clamp; 11-top rod; 12-pressing ring clamp; 13-limit sensor; 14-temperature sensor; 15-water inlet flow switch; 16-water outlet flow switch. 8-1 is an upper coil; 8-2 is an iron core; 8-3 is a lower coil; 8-4 is a magnetostrictive ring; 10-1 is a positioning thread hole; 10-2 is an anti-rotation groove; 10-3 is a side step; 10-4 is a side through hole; 10-5 is a center through hole. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be described below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0040] In the description of the present application, it should be noted that the terms "upper", "lower", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict.

[0043] From Figures 1 to 4 A water magnetic field coupling magnetostrictive backfill friction spot welding method and device provided by the present application, Figure 1 A backfill friction spot welding use state diagram provided in the embodiment of the present application, Figure 2 A schematic diagram of an electromagnetic transducer, Figure 3 A schematic diagram of a matching top clamp; Figure 4 A coil energization circuit diagram.

[0044] As Figure 1 The water magnetic field coupling magnetostrictive backfill friction spot welding method and device provided by the present application includes a stirring needle 1, a sleeve 2, a compression ring 3, a welding material 6, a compression ring chuck 12, a top clamp 10, a top rod 11, a cap 4, an electromagnetic transducer 8, a magnetic ring 9, a fixed connecting rod 7, a water tank 5, a water inlet switch 15, a water outlet switch 16, a temperature sensor 14 and a limit sensor 13. The top clamp 10 is fixed in the compression ring chuck 12, and the internal top rod 11 cooperates to fix the welding material. The fixed connecting rod 7 is sequentially sleeved with the magnetostrictive ring 9, the cap 4 and the coil 8, and the four are concentrically matched. The water tank 5 is submerged in the water pool of the welding material 6 and slightly invades the compression ring 3, the sleeve 2 and the stirring needle 1.

[0045] As Figure 2 The structure of the electromagnetic transducer includes: an upper coil 8-1, an upper coil core 8-2, a lower coil 8-3 and a magnetostrictive ring 8-4. The upper coil and the lower coil are both wound in the same direction and then connected in series. The upper coil core 8-2 is placed inside the blind hole 4 at the bottom of the cap, and the upper coil is wound around the outer wall at the bottom of the cap 4. The entire electromagnetic transducer 8 penetrates into the fixed connecting rod 7.

[0046] As Figure 3As shown, the structure of the top clamp includes: the top clamp center through hole 10-5 embedded in the compression ring clamp 12. The side wall threaded hole 10-1 fixes the top clamp 10 in the compression ring clamp 12; the anti-rotation groove 10-2 avoids the rotation of the top clamp 10 by passing through the fixed nut of the compression ring 3; the side step 10-3 abuts against one end of the welding material, and the top rod 11 passes through the side through hole 10-4 to press the welding material. The top rod 11 cooperates with the measuring through hole 10-5, which can be a threaded cooperation or a spring cooperation, and the side step 10-3 fixes the welding material, and the two top rods act on the two welding materials with a width greater than 3 / 4 of the overlapping area.

[0047] As shown in the figure, the pulse current or alternating current such as sine / cosine current, sawtooth wave current, etc. is supplied to the coil for different welding stages. Figure 4 The coil is coated with waterproof paint on the outside and wrapped with a high polymer material to avoid corrosion, and a water-copper pipe can also be used without a water tank. In the preheating stage, the upper coil is separately powered, and the relay contacts K1 and K3 are connected; in the welding stage, the upper and lower coils are powered at the same time, and the relay contacts K1 and K4 are connected; in the shaping stage, the lower coil is separately powered, and the relay contacts K2 and K4 are connected. Double power sources can also be used to separately drive the two windings.

[0048] The present application also provides a welding process adjustment electromagnetic coupling magnetostriction method, which uses the above welding tool, including the following steps:

[0049] Step 1: Fix the welding material on the top clamp to ensure that the welding material does not rotate during the welding process;

[0050] Step 2: The sleeve is lowered to the surface of the pad, and the preheating stage begins, at which time the upper coil is connected, and only the Joule heat and electromagnetic force are excited;

[0051] Step 3: The lower and upper coils are connected at the same time in the lower and upper stages, and the Joule heat effect, electromagnetic force and ultrasonic vibration are excited;

[0052] Step 4: In the shaping stage, the lower coil is connected, and only ultrasonic vibration is excited.

[0053] The present application also provides a method for controlling the flow of the water tank based on temperature, which uses the above welding tool, including the following steps:

[0054] Step 1: Fix the welding material on the top clamp to ensure that the welding material does not rotate during the actual welding process, and the introduced water is always at room temperature;

[0055] Step 2: The water level of the water tank is always higher than the welding material by the limit sensor on the horizontal surface of the welding material. When the water level is lower than the travel sensor, only the water inlet switch is connected, and the water inlet switch and the water outlet switch are in the same state in other cases. The water flow switch is divided into 8 grades.

[0056] Step3: Set the temperature of the pool, assume X °, measure the pool temperature Y °, when X > Y, the coil is powered on, the water flow switch is closed, when X < Y, the preheating stage begins, the water flow switch is opened;

[0057] Step4: In the process of the lower and back, the water flow switch adjusts the gear according to the temperature change, gear = (Y-X) / 10, less than zero, the water flow switch is closed;

[0058] Step5: The welding is finished, the water flow switch is closed.

[0059] Obviously, the above embodiments are only for clearly illustrating the structure of the welding tool and the method, and are not limited to the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An underwater magnetic field coupled magnetostrictive backfill friction spot welding device, characterized in that, The system includes a stirring needle, a clamping ring, welding material, a clamping ring chuck, a top clamp, a gasket, an electromagnetic transducer, a magnetic ring, a fixing rod, and a water tank. The top clamp is fitted with the clamping ring chuck, which, in conjunction with an internal top rod, secures the welding material at the bottom of the electric spindle. The fixing rod is fitted with the electromagnetic transducer and the gasket in sequence, all three concentrically positioned at the bottom center of the weld point. Magnetic field energy is converted into electrical and mechanical energy by the electromagnetic transducer and delivered to the weld point. The stirring needle faces the surface of the welding material. The welding material is submerged in the water tank, and the water flow is adjusted according to temperature changes. The electromagnetic transducer comprises an upper coil, an iron core, a lower coil, and a magnetostrictive ring. The upper and lower coils are wound in the same direction. The magnetostrictive ring is made of super magnetostrictive material, and its outer diameter matches the outer diameter of the bottom of the gasket. The upper and lower coils are designed for different applications. During the welding stage, the system is energized individually or simultaneously with alternating current. The electromagnetic transducer, gasket, and magnetic ring are mounted as a whole on the upper end of the fixed connecting rod. The bottom surface of the electromagnetic transducer contacts the stepped surface of the fixed connecting rod. The gasket is fixed to the boss of the fixed connecting rod, and the electromagnetic transducer is wrapped around the outside of the boss. The magnetic ring wraps around the entire electromagnetic transducer. The outer diameter of the magnetic ring is adjusted according to the characteristics of the material to be welded, and the magnetic wires at the connection interface of the welding point are horizontally distributed to form a vertical potential. The upper coil wraps around the gasket, which has an internal iron core. The lower coil wraps around the magnetostrictive ring. The boss of the fixed connecting rod passes through the blind hole at the bottom of the magnetostrictive ring and the gasket. The top of the fixed connecting rod is in close contact with the bottom surface of the gasket. The center hole of the magnetostrictive ring and the blind hole at the bottom of the gasket slide in fit with the top of the fixed connecting rod. The bottom surfaces of the magnetic ring and the electromagnetic transducer are in close contact with the stepped surface of the fixed connecting rod.

2. The underwater magnetic field coupled magnetostrictive backfill friction spot welding device according to claim 1, characterized in that, The gasket is made of austenitic stainless steel, titanium alloy or copper alloy, and a heat-insulating and wear-resistant coating is placed on its surface. The outer diameter of the top of the gasket is larger than the outer diameter of the sleeve and smaller than the outer diameter of the clamping ring. The outer diameter of the bottom is consistent with the inner diameter of the coil. The inner diameter of the blind hole at the bottom is consistent with the outer diameter of the iron core built into the electromagnetic transducer and the top outer diameter of the fixed connecting rod.

3. The underwater magnetic field coupled magnetostrictive backfill friction spot welding device according to claim 1, characterized in that, The coil is coated with waterproof paint and wrapped with corrosion-resistant material, or a water-conducting copper pipe can be used in the absence of a water tank.

4. The underwater magnetic field coupled magnetostrictive backfill friction spot welding device according to claim 1, characterized in that, In addition to its application in friction stir welding, electromagnetic transducers can also be used in additive manufacturing. As the height of the additive component changes, the variable resonance condition can be automatically adjusted by regulating the current frequency to ensure that the peak intensity of the excitation remains constant as the height of the additive component changes.

5. The underwater magnetic field coupled magnetostrictive backfill friction spot welding device according to claim 1, characterized in that, The clamping ring and the gasket fix the upper and lower end faces of the welding material, and the two end faces of the welding material are fixed by the top clamp. The top clamp includes a side wall threaded hole fixed on the clamping ring clamp, a central through hole concentric with the clamping ring chuck, and a fixing nut with an anti-rotation groove passing through the clamping ring to prevent the clamp from rotating. Its side step is close to one end of the welding material. It also includes a push rod passing through the side through hole of the top clamp. The push rod and the side through hole are in sliding fit, and a matching spring is used to hold the welding material, or the welding material is fixed by a threaded fit. The two push rods act on the overlapping 3 / 4 width area of ​​the two welding materials.

6. The underwater magnetic field coupled magnetostrictive backfill friction spot welding device according to claim 1, characterized in that, The water tank is equipped with an inlet flow switch and an outlet flow switch, as well as a limit sensor and a temperature sensor located at the bottom horizontal plane of the sleeve.

7. A method for regulating electromagnetic coupling magnetostriction during welding, characterized in that, Using the apparatus as described in claim 2 includes the following steps: Fix the welding material on the top fixture to ensure that the welding material does not rotate during the welding process; The sleeve is pressed down to the surface of the backing plate, and the preheating stage begins. At this time, the upper coil is energized, and only Joule heat and electromagnetic force are excited; During the pressing-down and retracting processes, both the upper coil and the lower coil are energized to excite the Joule heat effect, electromagnetic force, and ultrasonic vibration; In the forming stage, the lower coil is energized, and only ultrasonic vibration is excited.

8. A method for controlling water flow in a pool based on temperature, characterized in that, Using the device according to claim 2, comprising the following steps: Fix the welding material on the top fixture to ensure that it does not rotate during the actual welding process, and the introduced water is always at room temperature; The limit sensor at the horizontal plane of the welding material ensures that the water surface in the water tank is always higher than the welding material. When the water surface is lower than the travel sensor, only the water inlet switch is turned on. In other cases, the states of the water inlet switch and the water outlet switch are the same, and the water flow switch has 8 gears; Set the temperature of the water tank during the welding process to X °, measure the temperature of the water tank as Y °. When X ° ≥ Y °, the upper coil is powered on and the water flow switch is closed. When X ° < Y °, the preheating stage begins and the water flow switch is opened; During the pressing-down and retracting processes, the water flow switch adjusts the gear according to the temperature change. The gear number = integer value of (Y ° - X °) / 10. When it is less than zero, the water flow switch is closed; After welding is completed, turn off the water flow switch.

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