Handheld portable friction stir welding equipment adopting electromagnetic preheating and welding method

Abstract

The invention belongs to the technical field of friction stir welding, and discloses handheld portable friction stir welding equipment adopting electromagnetic preheating and a welding method. The motor is fixedly arranged in the first shell; the second shell is of a cylindrical structure with two open ends; one end of the second shell is fixedly connected to the first shell and is communicated with the inner cavity of the first shell; the stirring head clamping shaft is arranged in the second shell, and the stirring head clamping shaft and the second shell are coaxially arranged; one end of the stirring head clamping shaft is connected with an output shaft of the motor; the stirring head is installed at the other end of the stirring head clamping shaft, and the stirring head is located outside the second shell; the electromagnetic coil is fixedly arranged at the other end of the second shell, and the stirring head clamping shaft is sleeved with the electromagnetic coil in an empty mode; the electromagnetic coil controller is fixedly arranged in the first shell and connected with the electromagnetic coil through a wire.

Description

Technical Field

[0001] The invention belongs to the technical field of friction stir welding, and in particular relates to a handheld portable friction stir welding device and a welding method using electromagnetic preheating. Background Art

[0002] Friction stir welding is a high-quality solid phase welding method. Compared with traditional melting welding, friction stir welding has the advantages of being green and environmentally friendly, having high joint strength and small welding deformation. In recent years, it has been widely used in aerospace, rail transportation, shipbuilding and other fields. With the rapid development of the manufacturing industry, there is an increasing demand for friction stir welding in special environments such as space welding, on-orbit repair, underwater welding, and weapon equipment repair.

[0003] However, the current friction stir welding equipment is mainly large-scale equipment, and large-scale friction stir welding equipment is mostly installed in a fixed manner in an indoor environment. When the workpiece needs to be friction stir welded, it only needs to be transferred to the friction stir welding equipment for welding. Large-scale friction stir welding equipment cannot be moved outdoors for on-site operations. At this time, a small-scale friction stir welding equipment with a compact size, easy to carry and capable of outdoor welding is needed. However, as the equipment is reduced in size, the power output of the equipment will also decrease, resulting in the inability to achieve the power required for welding, affecting the welding effect; making the portability and miniaturization of the equipment slow to advance, which is a technical problem that needs to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a handheld portable friction stir welding device using electromagnetic preheating, which heats the welding material by setting an electromagnetic coil, thereby reducing the power demand for friction stir welding, reducing the volume of the welding device, and improving the welding efficiency.

[0005] Another object of the present invention is to provide a welding method using a handheld portable friction stir welding device with electromagnetic preheating, which can maintain the stability of the material heating temperature during the welding process and further ensure the welding quality.

[0006] The technical solution provided by the present invention is:

[0007] A portable handheld friction stir welding device using electromagnetic preheating, comprising:

[0008] first shell;

[0009] A motor, which is fixedly disposed in the first housing;

[0010] A second shell is a cylindrical structure with two ends open; one end of the second shell is fixedly connected to the first shell and communicates with the inner cavity of the first shell;

[0011] A stirring head clamping shaft, which is arranged in the second housing and coaxially arranged with the second housing; one end of the stirring head clamping shaft is connected to the output shaft of the motor;

[0012] A stirring head, which is mounted on the other end of the stirring head clamping shaft, and the stirring head is located outside the second housing;

[0013] An electromagnetic coil is fixedly arranged at the other end of the second housing, and the electromagnetic coil is hollowly sleeved on the clamping shaft of the stirring head;

[0014] The electromagnetic coil controller is fixedly arranged in the first shell and connected to the electromagnetic coil through a wire.

[0015] Preferably, the output shaft of the motor is connected to the agitator head clamping shaft via a coupling.

[0016] Preferably, the electromagnetic coil is a planar wound spiral coil and is coaxially arranged with the stirring head.

[0017] Preferably, a plurality of fixing blocks are fixedly disposed at the end of the second shell, and the plurality of fixing blocks are arranged at intervals along the circumferential direction of the opening of the second shell;

[0018] Wherein, a plurality of arc-shaped grooves are arranged on one side of the fixing block facing the inner cavity of the second shell, and the electromagnetic coil is matched and engaged in the arc-shaped grooves.

[0019] Preferably, the first housing is provided with heat dissipation holes arranged in an array.

[0020] Preferably, the portable handheld friction stir welding device using electromagnetic preheating further comprises:

[0021] The temperature sensor is fixedly mounted on the second housing and is arranged close to the electromagnetic coil.

[0022] Preferably, a gripping handle is fixedly mounted on the first housing.

[0023] A welding method using a handheld portable friction stir welding device using electromagnetic preheating, using the handheld portable friction stir welding device using electromagnetic preheating, comprising:

[0024] Place the stirring head at the welding position and turn on the electromagnetic coil to preheat the welding material;

[0025] During the preheating process, the temperature of the electromagnetic coil is detected in real time; when it is detected that the temperature reaches the target temperature, the stirring head is started for welding;

[0026] During the welding process, the power output of the electromagnetic coil is controlled by the electromagnetic coil controller to ensure that the heating temperature remains stable during the welding process.

[0027] Preferably, during the welding process, the output power of the electromagnetic coil is controlled according to the following formula:

[0028]

[0029] Among them, P base is the basic power, P unit is the unit power, T diff is the difference between the current temperature of the electromagnetic coil and the target temperature, T unit is the unit temperature, K p is the proportional gain coefficient, p i To increase the power percentage, p d To reduce the power percentage, H1(T diff ) and H2(T diff ) are step functions, when T diff When H1(T diff ) takes the value of 1, otherwise H1(T diff ) takes the value of 0, when T diff When H2(T diff ) takes the value of 0, otherwise H2(T diff ) takes the value of 1.

[0030] Preferably, the welding method using the handheld portable friction stir welding device with electromagnetic preheating further comprises: current Adjust the parameters in the formula;

[0031] Among them, when 0℃≤T current <250℃, set K p =2.5, p i =25%, p d =5%;

[0032] When 250℃≤T current <500℃, set K p =1.2, p i =12%, p d =12%;

[0033] When T current ≥500℃, set K p =0.8, p i =8%, p d =25%.

[0034] The beneficial effects of the present invention are:

[0035] The handheld portable friction stir welding equipment using electromagnetic preheating provided by the present invention heats the welding material before the welding operation officially starts and during the welding process by arranging an electromagnetic coil at the stirring head, so that the output power required by the welding equipment during operation is greatly reduced, thereby reducing the size of the equipment and solving the technical problem of miniaturization of the equipment.

[0036] The handheld portable friction stir welding equipment using electromagnetic preheating provided by the present invention makes the welding material more easily plasticized by the stirring head through the heating of the electromagnetic coil, reduces the upsetting force and forward resistance required by the stirring head during the welding process, can maintain stable welding quality at a higher welding speed, reduces the wear rate of the stirring head, and increases the service life of the stirring head.

[0037] The welding method of the handheld portable friction stir welding equipment using electromagnetic preheating provided by the present invention can maintain the stability of the material heating temperature during the welding process, and further ensure the welding quality.

[0038] The welding method of the handheld portable friction stir welding equipment using electromagnetic preheating provided by the present invention can improve the heating efficiency and avoid damage to the welding material by controlling the heating process according to the current temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the external structure of the handheld portable friction stir welding equipment using electromagnetic preheating according to the present invention.

[0040] Figure 2 It is a schematic diagram of the arrangement of the heat dissipation holes described in the present invention.

[0041] Figure 3 The figure is a schematic diagram of the internal structure of the handheld portable friction stir welding equipment using electromagnetic preheating according to the present invention.

[0042] Figure 4 It is a structural schematic diagram of the fixing block described in the present invention.

[0043] Figure 5 This is a schematic diagram of the temperature control and feedback principle of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0045] like Figure 1-4As shown, the present invention provides a handheld portable friction stir welding device using electromagnetic preheating, which mainly includes: a first shell 110, a second shell 120, a motor 130, a stirring head clamping shaft 140, a stirring head 150, an electromagnetic coil 160 and an electromagnetic coil controller 170.

[0046] The motor 130 is fixedly arranged in the first shell 110. The second shell 120 is a cylindrical structure with openings at both ends; one end (opening) of the second shell 120 is fixedly connected to the first shell 110 and communicates with the inner cavity of the first shell 110. The stirring head clamping shaft 140 is arranged in the second shell 120 and is coaxially arranged with the second shell 120. One end of the stirring head clamping shaft 140 is connected to the output shaft of the motor 130 through a coupling 141. The stirring head 150 is detachably mounted on the other end of the stirring head clamping shaft 140, and the stirring head 150 is located outside the second shell 120. The stirring head 150 can be driven to rotate by the motor 130 to realize the working process of stir friction welding.

[0047] The electromagnetic coil 160 is fixedly arranged at the other end (opening) of the second housing 120, and the electromagnetic coil 160 is hollowly sleeved on the stirring head clamping shaft 140. The electromagnetic coil controller 170 is fixedly arranged in the first housing 110, and the electromagnetic coil controller 170 is connected to the electromagnetic coil 160 through a wire. The output power of the electromagnetic coil 160 can be changed through the electromagnetic coil controller 170, thereby changing the heating temperature of the electromagnetic coil 160.

[0048] As a preference, the electromagnetic coil 160 is configured as a planar wound spiral coil, and the electromagnetic coil 160 is coaxially arranged with the stirring head 150; this can ensure that the electromagnetic coil 160 is closer to the welding material and increase the heating range of the electromagnetic coil 160 as much as possible.

[0049] A plurality of fixing blocks 121 are fixedly arranged at the end of the second housing 120 (the end where the electromagnetic coil 160 is arranged), and the plurality of fixing blocks 121 are arranged at intervals along the circumferential direction of the opening of the second housing 120. Among them, a plurality of arc-shaped grooves 121a are arranged on the side of the fixing blocks 121 facing the inner cavity of the second housing 120, and the spiral parts of the electromagnetic coil 160 are matched and engaged in the arc-shaped grooves 121a one by one, thereby realizing the position limitation of the electromagnetic coil 160. Among them, the number of the fixing blocks 121 is at least 3.

[0050] As a preferred embodiment, the first housing 110 is provided with heat dissipation holes 111 arranged in an array for dissipating heat from the motor 130 to ensure stable operation of the motor 130 .

[0051] A gripping handle 180 is fixedly mounted at the lower end of the first housing 110 to facilitate the user to perform welding operations. A switch 112 is also provided at the lower end of the first housing 110 to facilitate turning on or off the welding device.

[0052] As a preference, the friction stir welding equipment is further provided with a temperature sensor 161 for real-time detection of the temperature of the electromagnetic coil 160 . The temperature sensor 161 is fixedly mounted on one end of the second shell 120 where the electromagnetic coil 160 is provided, and the temperature sensor 161 is provided close to the electromagnetic coil 160 .

[0053] As a preference, a display screen 190 is also fixedly mounted on the side of the first shell 110 , and the display screen 190 can display data such as the pressure and rotation speed of the stirring head 150 , and the current temperature of the electromagnetic coil 160 .

[0054] The present invention sets an electromagnetic coil near the stirring head, generates eddy currents inside the metal object through electromagnetic induction, and then uses the resistance thermal effect of the eddy currents to heat the welding material. Before welding begins, the welding material is preheated by the electromagnetic coil so that it quickly heats the workpiece (welding material) to the required temperature. At the same time, the electromagnetic coil continues to heat during the welding process, making the welding material easier to be plasticized by the stirring head, reducing the upsetting force and forward resistance required by the stirring head during the welding process, thereby reducing the power required for the welding equipment to operate, reducing the load of the motor, and improving the overall welding efficiency.

[0055] The present invention also provides a welding method using a handheld portable friction stir welding device with electromagnetic preheating. The specific process of using the handheld portable friction stir welding device with electromagnetic preheating is as follows.

[0056] Place the stirring head in the welding (initial) position and turn on the electromagnetic coil to preheat the welding material. During the preheating process, the temperature of the electromagnetic coil is detected in real time by the temperature sensor; when the temperature reaches the target temperature, the stirring head is started for welding. During the welding process, the power output of the electromagnetic coil is controlled by the electromagnetic coil controller to ensure that the heating temperature remains stable during the welding process.

[0057] (1) Electromagnetic coil preheating stage

[0058] The electromagnetic coil is fixed near the stirring head. When energized, it generates eddy currents and heats the welding (metal) material through resistance. The design of the electromagnetic coil should take into account the conductivity of the material and the size of the preheating area. The handheld portable friction stir welding equipment uses electromagnetic induction to preheat the metal material and achieves welding through the mechanical force and speed applied by the stirring head. The working process of the equipment is divided into preheating stage and welding stage, combined with temperature feedback control to ensure temperature stability during welding.

[0059] By formula Q prc =P coil ·t, the power P of the electromagnetic coil coil (W), determines the heating rate; t, the heating time (s), depends on the thermal conductivity of the material, the size of the preheating area, and the required temperature change.

[0060] The heat required for material heating Q can be calculated by the following formula required =m·c·ΔT.

[0061] Where m is the mass of the material (kg), c is the specific heat capacity of the material (J / (kg·K)), and ΔT is the temperature rise of the material.

[0062] To ensure that the preheating process provides sufficient heat, the following conditions must be met: Q pre ≥Q required .

[0063] Among them, Q pre Indicates the heat generated by preheating, Q required Indicates the amount of heat a material is heated to.

[0064] (2) Welding stage

[0065] The stirring head and the electromagnetic coil jointly provide the heat required in the welding process to achieve the plasticizing effect. At the same time, since the coverage area of ​​the electromagnetic coil is larger than the working area of ​​the stirring head, during the working process of the stirring head, the electromagnetic coil can radiate to the unwelded area and continue to preheat the unwelded area.

[0066] The formula for the heat generated by the stirring head is: Q weld =F·v·η.

[0067] Where F is the applied force (N), v is the welding speed (m / s), and η is the thermal efficiency, which is usually between 0.6 and 0.9.

[0068] (3) Temperature control and feedback mechanism

[0069] The handheld portable friction stir welding equipment is equipped with a main controller, which is electrically connected to the electromagnetic coil controller and is responsible for monitoring the current temperature and automatically adjusting the power output of the electromagnetic coil according to the set target temperature to ensure that the welding material remains in the appropriate temperature range during the welding process. Figure 5 shown.

[0070] As a preferred embodiment, during the welding process, the output power of the electromagnetic coil is controlled according to the following formula:

[0071]

[0072] Among them, P base is the basic power (W), P unit is the unit power, P unit =1W, T diff is the difference between the current temperature and the target temperature (°C), T unit is the unit temperature, T unit =1℃,K p is the proportional gain coefficient, p i To increase the power percentage, p d To reduce the power percentage, H1(T diff ) and H2(T diff ) are step functions, when T diff When H1(T diff ) takes the value of 1, otherwise H1(T diff ) takes the value of 0, when T diff When H2(T diff ) takes the value of 0, otherwise H2(T diff ) is 1. The base power is used to ensure that there is a minimum power output to meet the preheating requirements. It can be set to the middle value of the electromagnetic coil output power or determined based on experience. Dynamically adjust the power output according to the temperature difference to ensure a fast response of the equipment. Boost and reduce power are used to dynamically adjust the output power according to the temperature changes to adapt to the temperature requirements during the welding process.

[0073] Since the handheld portable friction stir welding equipment is generally only used for spot welding operations, the required maximum temperature is about 1000° C. As a preferred embodiment, different temperature adjustment strategies are set according to different temperature stages in the present invention to ensure heating efficiency and to ensure that the welding material will not be damaged due to overheating.

[0074] The specific method is: according to the current temperature T current (℃) Adjust the parameters in the formula:

[0075] When the current temperature is detected to be in the low temperature range, that is, 0℃≤T current <250℃, set K p =2.5, p i =25%, p d =5%; quickly reach the target temperature and improve heating efficiency.

[0076] When the current temperature is detected to be in the medium temperature range, that is, 250℃≤T current <500℃, set K p =1.2, p i =12%, p d =12%; ensure heating temperature is stable.

[0077] When the current temperature is detected to be in the high temperature range, that is, T current ≥500℃, set K p =0.8, p i =8%, p d = 25%, avoid overheating.

[0078] The present invention sets different temperature adjustment strategies according to different temperature stages, which mainly include two parts: sensitivity adjustment and response adjustment. Sensitivity adjustment is reflected in: K p It can be adjusted according to the response characteristics of the system to ensure that when there is a gap between the target temperature and the actual temperature, the system can follow sensitively and robustly. Response adjustment is reflected in: timely adjustment of P according to the actual temperature requirements during welding. i and P d To achieve a balance between fast response and stable output.

[0079] The above adjustment method can effectively realize dynamic control of welding temperature, ensure the stability and reliability of welding process, and thus improve welding quality and service life of welding equipment.

[0080] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A portable handheld friction stir welding device using electromagnetic preheating, characterized in that: include: first shell; A motor, which is fixedly disposed in the first housing; A second housing, which is a cylindrical structure with openings at both ends; One end of the second shell is fixedly connected to the first shell and communicates with the inner cavity of the first shell; A stirring head clamping shaft, which is arranged in the second housing and coaxially arranged with the second housing; one end of the stirring head clamping shaft is connected to the output shaft of the motor; A stirring head, which is mounted on the other end of the stirring head clamping shaft, and the stirring head is located outside the second housing; An electromagnetic coil is fixedly arranged at the other end of the second housing, and the electromagnetic coil is hollowly sleeved on the clamping shaft of the stirring head; The electromagnetic coil controller is fixedly arranged in the first shell and connected to the electromagnetic coil through a wire.

2. The portable handheld friction stir welding device using electromagnetic preheating according to claim 1, characterized in that: The output shaft of the motor is connected to the agitator head clamping shaft through a coupling.

3. The portable handheld friction stir welding device using electromagnetic preheating according to claim 2, characterized in that: The electromagnetic coil is a planar wound spiral coil and is coaxially arranged with the stirring head.

4. The portable handheld friction stir welding device using electromagnetic preheating according to claim 3 is characterized in that: A plurality of fixing blocks are fixedly disposed at the end of the second shell, and the plurality of fixing blocks are arranged at intervals along the circumferential direction of the opening of the second shell; Wherein, a plurality of arc-shaped grooves are arranged on one side of the fixing block facing the inner cavity of the second shell, and the electromagnetic coil is matched and engaged in the arc-shaped grooves.

5. The portable handheld friction stir welding device using electromagnetic preheating according to claim 1 or 4, characterized in that: The first housing is provided with heat dissipation holes arranged in an array.

6. The portable handheld friction stir welding device using electromagnetic preheating according to claim 5, characterized in that: Also includes: The temperature sensor is fixedly mounted on the second housing and is arranged close to the electromagnetic coil.

7. The portable handheld friction stir welding device using electromagnetic preheating according to claim 1, characterized in that: A gripping handle is fixedly mounted on the first shell.

8. A welding method using a handheld portable friction stir welding device with electromagnetic preheating, using the handheld portable friction stir welding device with electromagnetic preheating as claimed in any one of claims 1 to 7, characterized in that: include: Place the stirring head at the welding position and turn on the electromagnetic coil to preheat the welding material; During the preheating process, the temperature of the electromagnetic coil is detected in real time; when it is detected that the temperature reaches the target temperature, the stirring head is started for welding; During the welding process, the power output of the electromagnetic coil is controlled by the electromagnetic coil controller to ensure that the heating temperature remains stable during the welding process.

9. The welding method of claim 8, wherein the handheld portable friction stir welding device using electromagnetic preheating is characterized in that: During the welding process, the output power of the electromagnetic coil is controlled according to the following formula: Among them, P base is the basic power, P unit is the unit power, T diff is the difference between the current temperature of the electromagnetic coil and the target temperature, T unit is the unit temperature, K p is the proportional gain coefficient, p i To increase the power percentage, p d To reduce the power percentage, H1(T diff ) and H2(T diff ) are step functions, when T diff When H1(T diff ) takes the value of 1, otherwise H1(T diff ) takes the value of 0, when T diff When H2(T diff ) takes the value of 0, otherwise H2(T diff ) takes a value of 1.

10. The welding method of claim 9 using a handheld portable friction stir welding device with electromagnetic preheating, characterized in that: Also includes: According to the current temperature T of the electromagnetic coil current Adjust the parameters in the formula; Among them, when 0℃≤T current <250℃, set K p =2.5, p i =25%, p d =5%; When 250℃≤T current <500℃, set K p =1.2, p i =12%, p d =12%; When T current ≥500℃, set K p =0.8, p i =8%, p d =25%.

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