Infrared induction feedback type permanent magnet magnetic field auxiliary TIG (Tungsten Inert Gas) welding device and working method thereof

Abstract

The invention discloses an infrared induction feedback type permanent magnet magnetic field auxiliary TIG (Tungsten Inert Gas) welding device and a working method thereof, and the device comprises a TIG welding gun arranged above a workpiece, a welding power supply connected with a tungsten electrode in the TIG welding gun, a permanent magnet group arranged above the workpiece, and a magnet driving mechanism for driving the permanent magnet group, the infrared temperature detector is arranged on the side surface of the workpiece; the driving permanent magnet set and the infrared temperature detector are both connected with the control system, the infrared temperature detector detects the arc temperature distribution condition in real time and feeds back the detected arc temperature to the control system, and the control system compares the arc temperature with a preset threshold value and sends a control signal to the magnet driving mechanism according to the comparison result. The magnet driving mechanism adjusts the distance between the two permanent magnets in the permanent magnet group and the electric arc based on the control signal, and dynamic adjustment of the magnetic field intensity is achieved. According to the invention, the size of the magnetic field can be flexibly changed, and high energy consumption and electromagnetic interference of the electromagnetic coil can be avoided.

Description

Technical Field

[0001] The present invention relates to the technology of optimizing welding processes, and particularly to an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device and its working method. Background Art

[0002] TIG welding (tungsten inert gas welding) is an arc welding technology that uses a non-consumable tungsten electrode and an inert gas (usually argon) for protection. Due to the use of a non-consumable tungsten electrode, the heat input of TIG welding is relatively low, the heat affected zone is small, and it is suitable for welding thin plates and components prone to deformation. However, TIG welding has high requirements for the welding environment, slow welding speed, and low efficiency. Especially for TIG welding of thin stainless steel plates, there are often problems such as poor weld formation quality and low strength of the welded joint. The traditional TIG welding technology has been difficult to meet the current industrial requirements.

[0003] In recent years, researchers in this field have developed magnetic field assisted TIG welding technology to improve the quality and efficiency of TIG welding. By applying an external magnetic field (static magnetic field, alternating magnetic field or composite magnetic field) during TIG welding, the arc shape and molten pool flow are affected, the welding heat input and metallurgical behavior are regulated, and finally the purpose of improving welding quality and enhancing welding efficiency is achieved. The existing types of auxiliary magnetic fields are static magnetic fields and alternating magnetic fields. The static magnetic field uses permanent magnets (such as neodymium iron boron) or electromagnetic coils, with a stable magnetic field intensity (0.05 - 0.3T), low cost but poor adjustment flexibility. The alternating magnetic field generates a frequency adjustable magnetic field (50 - 500Hz) through an electromagnetic coil, dynamically controlling the arc shape and molten pool flow, but requires additional power supply and the equipment is complex. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device and its working method, which can not only flexibly change the magnitude of the magnetic field, but also avoid the high energy consumption and electromagnetic interference of electromagnetic coils.

[0005] Technical solution: An infrared induction feedback type permanent magnet magnetic field assisted TIG welding device of the present invention includes a TIG welding torch placed above the workpiece for performing TIG welding on the workpiece, a welding power source connected to the tungsten electrode in the TIG welding torch, a permanent magnet group placed above the workpiece, a magnet driving mechanism for driving the permanent magnet group, and an infrared temperature detector placed on the side of the workpiece; the driving permanent magnet group and the infrared temperature detector are both connected to a control system. The infrared temperature detector is used to detect the arc temperature distribution in real time and feed back the detected arc temperature to the control system. The control system is used to compare the arc temperature with a preset threshold value and send a control signal to the magnet driving mechanism according to the comparison result. The magnet driving mechanism is used to adjust the distance between the two permanent magnets in the permanent magnet group and the arc based on the control signal to realize the dynamic adjustment of the magnetic field intensity.

[0006] Further, the workpiece is made of a stainless steel thin plate, and this device is suitable for performing TIG welding on stainless steel thin plates with a thickness of 0.5 - 2 mm.

[0007] Further, when the detected arc temperature exceeds the preset threshold value, the magnet driving mechanism reduces the distance between the two permanent magnets in the permanent magnet group and the arc until the magnetic field intensity increases to 0.05 - 0.3 T; when the detected arc temperature is less than the preset threshold value, the magnet driving mechanism increases the distance between the two permanent magnets in the permanent magnet group and the arc.

[0008] Further, a wire feeding mechanism is provided above the workpiece.

[0009] Further, the TIG welding torch is connected to a gas cylinder.

[0010] Further, the permanent magnet group is a rare earth permanent magnet neodymium iron boron magnet group, and the surface of the rare earth permanent magnet neodymium iron boron magnet group is nickel-plated.

[0011] Based on the same inventive concept, a working method of an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device of the present invention is applied to the above-mentioned infrared induction feedback type permanent magnet magnetic field assisted TIG welding device. This working method includes:

[0012] Fix the workpiece on a water-cooled workpiece table and adjust the initial distance between the two permanent magnets in the permanent magnet group to a preset value;

[0013] Set the threshold value T of the infrared temperature in the control system 0 to be 1400 - 1600 °C, start argon protection, and set the flow rate of the gas cylinder to 10 - 20 L / min;

[0014] Turn on the welding power source, set the current I to 30 - 80 A, and after the tungsten electrode in the TIG welding torch is electrified to generate an arc, start welding;

[0015] The infrared temperature detector collects the arc temperature T in real time and feeds it back to the control system. The control system calculates the optimal distance between the two permanent magnets in the permanent magnet group and the arc through the built-in adjustment algorithm, and sends it to the magnet driving mechanism. The magnet driving mechanism adjusts the permanent magnet group according to the calculated optimal distance between the two permanent magnets in the permanent magnet group and the arc;

[0016] Set the welding speed v to 100 - 1000 mm / min, and the magnetic field strength is inversely linked to the welding speed.

[0017] Furthermore, the adjustment algorithm of the control system satisfies the following relational expression:

[0018]

[0019] where d is the distance between the two permanent magnets in the permanent magnet group; T is the real-time detected temperature; T 0 is the set reference temperature; K is the proportionality coefficient; n is the exponential term.

[0020] Furthermore, the value range of the exponential term n is 1.2 - 1.8.

[0021] Furthermore, when the infrared temperature detector collects the arc temperature T > T 0 the magnet driving mechanism reduces the distance between the two permanent magnets in the permanent magnet group and the arc to d = 5 - 15 mm; when T < T 0 the magnet driving mechanism increases the distance between the two permanent magnets in the permanent magnet group and the arc to d = 20 - 50 mm.

[0022] Beneficial effects: Compared with the prior art, the remarkable technical effects of the present invention are as follows:

[0023] The present invention adds an infrared temperature detector, a magnet driving mechanism and the control system therebetween in the permanent magnet assisted TIG welding device. During the welding process, the temperature of the arc is monitored in real time by the infrared temperature detector, and the temperature detection result is fed back to the control system. When the collected arc temperature T > T 0 the magnet driving mechanism reduces the distance between the two permanent magnets in the permanent magnet group and the arc; when T < T 0 the magnet driving mechanism increases the distance between the two permanent magnets in the permanent magnet group and the arc. The control system calculates the optimal distance between the two permanent magnets in the permanent magnet group and the arc through the built-in adjustment algorithm, and sends it to the magnet driving mechanism. The magnet driving mechanism adjusts the distance between the permanent magnet and the arc according to the calculated distance between the two permanent magnets in the permanent magnet group and the arc, realizes the dynamic adjustment of the magnetic field magnitude applied to the arc and the weld pool, establishes a dynamic mapping relationship between the arc temperature fluctuation and the magnetic field magnitude, and forms a ternary collaborative control process of "temperature monitoring - magnetic field adjustment - weld pool behavior optimization".

[0024] The present invention combines the dual advantages of static magnetic fields and dynamic magnetic fields, enabling flexible changes in the magnetic field magnitude while avoiding the high energy consumption and electromagnetic interference of electromagnetic coils in traditional dynamic magnetic field generating devices.

[0025] The technical welding process of the present invention is more stable, and the weld forming effect is significantly better than that of traditional welding modes. The width of the heat affected zone, porosity, and deformation amount are greatly reduced, and the strength of the welded joint after welding is much greater than that of traditional welding processes. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device disclosed in an embodiment of the present invention. Detailed Embodiments

[0027] The technical solutions of the present invention will be introduced in detail below in conjunction with the detailed embodiments and the drawings of the specification.

[0028] As Figure 1 shown, an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device of the present invention includes a welding power source 1, a TIG welding torch 2, a wire feeding mechanism 3, a gas cylinder 4, an infrared temperature detector 5, a permanent magnet group 6, a magnet driving mechanism 7, and a control system 8. The TIG welding torch 2 is placed above the workpiece for TIG welding of the workpiece, and the welding power source 1 is connected to the tungsten electrode in the TIG welding torch 2. A wire feeding mechanism 3 is provided above the workpiece, and the wire feeding mechanism 3 evenly feeds the welding wire to the welding area to be welded. The TIG welding torch 2 is connected to the gas cylinder 4. The gas cylinder 4 transports argon to the welding area to be welded through the TIG welding torch 2, thereby exhausting the air in the welding area to be welded and making the area above the welded part in a pure argon protection state. The infrared temperature detector 5 is placed on the side of the workpiece. The detection wavelength of the infrared temperature detector 5 is 2 - 5 μm, the sampling frequency ≥ 100 Hz, and the temperature resolution is ±5°C. The permanent magnet group 6 is placed above the workpiece. In this embodiment, the permanent magnet group 6 is a rare earth permanent magnet neodymium iron boron magnet group, and the surface of the rare earth permanent magnet neodymium iron boron magnet group is nickel plated, with a remanence ≥ 1.2 T and a working temperature ≤ 250°C. The magnet driving mechanism 7 is used to drive the permanent magnet group 6, and the displacement accuracy of the magnet driving mechanism 7 is ±0.1 mm, and the response time ≤ 50 ms. In this embodiment, the workpiece uses a stainless steel thin plate, and this infrared induction feedback type permanent magnet magnetic field assisted TIG welding device is suitable for TIG welding of 0.5 - 2 mm stainless steel thin plates.

[0029] The driving permanent magnet group 6 and the infrared temperature detector 5 are both connected to the control system 8. The infrared temperature detector 5 is used to detect the arc temperature distribution in real time and feed back the detected arc temperature to the control system 8. The control system 8 is used to compare the arc temperature with a preset threshold value and send a control signal to the magnet driving mechanism 7 according to the comparison result. The magnet driving mechanism 7 is used to adjust the distance between the two permanent magnets in the permanent magnet group 6 and the arc based on the control signal, so as to realize the dynamic adjustment of the magnetic field intensity.

[0030] When the detected arc temperature exceeds the preset threshold value, the magnet driving mechanism 7 reduces the distance between the two permanent magnets in the permanent magnet group 6 and the arc until the magnetic field intensity increases to 0.05 - 0.3 T; when the detected arc temperature is less than the preset threshold value, the magnet driving mechanism 7 increases the distance between the two permanent magnets in the permanent magnet group 6 and the arc.

[0031] A working method of an infrared induction feedback type permanent magnet magnetic field assisted TIG welding device of the present invention includes the following steps:

[0032] S1. Fix the stainless steel thin plate on the water-cooled workpiece table and modulate the initial distance between the two permanent magnets in the permanent magnet group 6 and the arc to a preset value; in this embodiment, the preset value d of the initial distance 0 = 20 mm.

[0033] S2. Set the threshold value T of the infrared temperature in the control system 8 0 to 1400 - 1600 °C, start argon protection, and set the flow rate of the gas cylinder 4 to 10 - 20 L / min;

[0034] S3. Turn on the welding power supply 1, set the current I to 30 - 80 A, the tungsten electrode in the TIG welding torch 2 is electrified to generate an arc, and start welding;

[0035] S4. The infrared temperature detector 5 detects the arc temperature T in real time and feeds it back to the control system 8. The control system 8 calculates the optimal distance between the two permanent magnets in the permanent magnet group 6 and the arc through a built-in adjustment algorithm and sends it to the magnet driving mechanism 7. The magnet driving mechanism 7 adjusts the permanent magnet group 6 according to the calculated optimal distance between the two permanent magnets in the permanent magnet group 6 and the arc.

[0036] In this embodiment, the adjustment algorithm of the control system 8 satisfies the following relational expression:

[0037]

[0038] where d is the distance between the two permanent magnets in the permanent magnet group and the arc; T is the arc temperature detected in real time; T 0Let \(T_0\) be the set reference temperature; \(K\) be the proportionality coefficient; \(n\) be the exponential term. In this embodiment, the value range of the exponential term \(n\) is \(1.2 - 1.8\).

[0039] When the arc temperature \(T\) detected by the infrared temperature detector 5 in real time is \(T>T_0\), 0 the magnet driving mechanism 7 reduces the distance between the two permanent magnets in the permanent magnet group 6 and the arc to \(d = 5 - 15\) mm; when \(T<T_0\), 0 the magnet driving mechanism 7 increases the distance between the two permanent magnets in the permanent magnet group 6 and the arc to \(d = 20 - 50\) mm.

[0040] In step S4, the delay time between the magnetic spacing adjustment and the temperature change is \(\leq0.1\) s.

[0041] S5. Set the welding speed \(v\) to \(100 - 1000\) mm / min, and the magnetic field strength is inversely proportional to the welding speed in a linked manner.

[0042] Principle of the invention: The present invention realizes the intelligent control of magnetic field-assisted TIG welding through innovative technology integration: First, a neodymium iron boron permanent magnet dynamic adjustment system is designed to change the distance between the permanent magnet and the arc (5 - 50 mm) in a mechanical displacement manner, and directly regulate the effective magnetic field strength (0.05 - 0.3 T) through physical position changes; on this basis, an infrared-magnetic field closed-loop control mechanism is constructed, and the distribution characteristics of the arc temperature field are captured in real time by a high-precision infrared temperature detector (sampling frequency \(\geq100\) Hz), and the temperature gradient data is fed back to the control system; further, combined with the unsteady heat transfer characteristics of thin plate welding, a non-linear exponential magnetic distance adjustment algorithm (\(d = K / (T - T_0)^n\)) is developed, where the introduction of the exponential term \(n\) (1.2 - 1.8) significantly enhances the response sensitivity of the system to temperature mutations. When local overheating (\(\Delta T>50^{\circ}C\)) is detected, the algorithm drives the permanent magnet to quickly approach the arc area within 0.1 second, and accelerates the convective heat dissipation of the molten pool through magnetic field enhancement (amplification up to 60%) to achieve the self-adaptive balance of heat input. 0 ) n ) where the introduction of the exponential term \(n\) (1.2 - 1.8) significantly enhances the response sensitivity of the system to temperature mutations. When local overheating (\(\Delta T>50^{\circ}C\)) is detected, the algorithm drives the permanent magnet to quickly approach the arc area within 0.1 second, and accelerates the convective heat dissipation of the molten pool through magnetic field enhancement (amplification up to 60%) to achieve the self-adaptive balance of heat input.

[0043] The technical effects of the present invention are verified through specific embodiments below.

[0044] Example 1

[0045] Welding a 0.5-mm-thick 316L stainless steel thin plate

[0046] Welding parameters: Current: 30 A (pulse frequency 3 Hz, base current 20 A, peak current 40 A), welding speed: 220 mm / min, argon gas flow rate: 12 L / min (protection gas ratio: Ar + 2% H 2 )

[0047] Permanent magnet parameters: Initial spacing: 15 mm (corresponding to a magnetic field strength of 0.15 T), movement range: 5 - 30 mm (magnetic field strength range 0.05 - 0.25 T).

[0048] Infrared control parameters: Reference temperature T 0 = 1350 °C, K = 3.0×10 4 , n = 1.8.

[0049] Real-time adjustment process: When the temperature at the center of the molten pool reaches 1420 °C, the distance between the magnet and the arc is automatically adjusted to 8 mm (magnetic field enhanced to 0.22 T) to inhibit local overheating; when the temperature drops to 1300 °C, the spacing returns to 25 mm (magnetic field weakened to 0.07 T) to prevent the molten pool from solidifying too quickly.

[0050] Comparative Example 1

[0051] The difference between Comparative Example 1 and Example 1 is that no magnetic field and infrared control system are applied during the welding process.

[0052] Table 1 shows the comparison of the welding quality of Example 1 and Comparative Example 1 after welding.

[0053] Table 1

[0054]

[0055] It can be seen from the comparison that the magnetic field dynamic regulation and infrared feedback technology of the present invention significantly improve the welding quality of ultra-thin plates, and have outstanding advantages in preventing burn-through (defect rate reduced by 100%), controlling deformation (reduced by 80%) and improving mechanical properties (strength increased by 14%), fully verifying the innovation and industrial application value of the patented technology.

[0056] Example 2

[0057] Welding a 0.8 mm thick 316L stainless steel thin plate

[0058] Welding parameters: Current: 35 A (pulse frequency 2.5 Hz, base current 25 A, peak current 45 A), welding speed: 180 mm / min, argon gas flow rate: 14 L / min (protective gas ratio: Ar + 1.5% H 2 ).

[0059] Permanent magnet parameters: Initial spacing: 18 mm (corresponding to a magnetic field strength of 0.13 T), movement range: 8 - 35 mm (magnetic field strength range 0.06 - 0.20 T).

[0060] Infrared control parameters: Reference temperature T 0 = 1400 °C, K = 2.8×10 4 , n = 1.6.

[0061] Real-time adjustment process: When the temperature at the center of the molten pool reaches 1480 °C, the distance between the magnet and the arc is automatically adjusted to 10 mm (the magnetic field is enhanced to 0.17 T), accelerating the heat dissipation of the molten pool; when the temperature drops to 1320 °C, the distance returns to 30 mm (the magnetic field is weakened to 0.06 T) to avoid excessive cooling of the molten pool.

[0062] Comparative Example 2

[0063] The difference between Comparative Example 2 and Example 2 is that no magnetic field and infrared control system are applied during the welding process.

[0064] Table 2 shows the comparison of the welding quality between Example 2 and Comparative Example 2 after welding.

[0065] Table 2

[0066]

[0067] It can be seen from the comparison that the dynamic magnetic field regulation and infrared feedback technology of the present invention significantly improve the welding quality of ultra-thin plates, greatly reducing the porosity and deformation amount, and the strength of the welded joint after welding is much greater than that of the traditional welding process.

[0068] Example 3

[0069] Welding a 1.2-mm-thick 304L stainless steel thin plate

[0070] Welding parameters: Current: 50 A (pulse frequency 2 Hz, base current 30 A, peak current 70 A), welding speed: 120 mm / min, argon gas flow rate: 16 L / min (shielding gas ratio: Ar + 1% H 2 )

[0071] Permanent magnet parameters: Initial distance: 20 mm (corresponding magnetic field strength 0.14 T), moving range: 10 - 40 mm (magnetic field strength range 0.05 - 0.20 T).

[0072] Infrared control parameters: Reference temperature T 0 = 1480 °C, K = 2.2×10 4 , n = 1.4.

[0073] Real-time adjustment process: When the temperature at the center of the molten pool reaches 1550 °C, the distance between the magnet and the arc is automatically adjusted to 12 mm (the magnetic field is enhanced to 0.18 T) to inhibit heat accumulation; when the temperature drops to 1400 °C, the distance returns to 32 mm (the magnetic field is weakened to 0.05 T) to avoid solidification shrinkage cracks in the molten pool.

[0074] Comparative Example 3

[0075] The difference between Comparative Example 3 and Example 3 is that no magnetic field and infrared control system are applied during the welding process.

[0076] Table 3 shows the comparison of the welding quality of Example 3 and Comparative Example 3 after welding.

[0077] Table 3

[0078]

[0079] Through comparison, it can be seen that the welding process of the technology of the present invention is more stable, the weld forming effect is significantly better than that of the comparative example, the width of the heat affected zone, the porosity and the deformation amount are greatly reduced, and the strength of the welded joint after welding is much greater than that of the traditional welding process.

[0080] Example 4

[0081] Welding a 1.5 mm thick 304L stainless steel thin plate

[0082] Welding parameters: Current: 65 A (pulse frequency 1.5 Hz, base current 40 A, peak current 90 A), welding speed: 90 mm / min, argon flow rate: 18 L / min (shielding gas ratio: Ar + 0.8% H 2 )

[0083] Permanent magnet parameters: Initial spacing: 25 mm (corresponding magnetic field strength 0.12 T), moving range: 15 - 45 mm (magnetic field strength range 0.05 - 0.18 T).

[0084] Infrared control parameters: Reference temperature T 0 = 1500 °C, K = 1.8×10 4 , n = 1.2.

[0085] Real-time adjustment process: When the temperature at the center of the molten pool reaches 1600 °C, the distance between the magnet and the arc is automatically adjusted to 15 mm (magnetic field enhanced to 0.15 T) to strengthen the convection of the molten pool; when the temperature drops to 1420 °C, the spacing returns to 35 mm (magnetic field weakened to 0.06 T) to prevent solidification shrinkage cracks.

[0086] Comparative Example 4

[0087] The difference between Comparative Example 4 and Example 4 is that no magnetic field and infrared control system are applied during the welding process.

[0088] Table 4 shows the comparison of the welding quality of Example 4 and Comparative Example 4 after welding.

[0089] Table 4

[0090]

[0091] As can be seen from the comparison, the heat input during the welding process of the technology of the present invention is lower, the weld forming effect is significantly better than that of the comparative example, the width of the heat affected zone, the porosity and the deformation amount are greatly reduced, and the strength of the welded joint after welding is much greater than that of the traditional welding process.

[0092] Example 5

[0093] Welding a 2mm thick 304L stainless steel thin plate

[0094] Welding parameters: Current: 75A (pulse frequency 1Hz, base current 50A, peak current 100A), welding speed: 70mm / min, argon flow rate: 20L / min (protection gas ratio: Ar + 0.5% N 2 )

[0095] Permanent magnet parameters: Initial spacing: 28mm (corresponding magnetic field strength 0.1T), moving range: 18 - 50mm (magnetic field strength range 0.04 - 0.15T).

[0096] Infrared control parameters: Reference temperature T 0 = 1520°C, K = 1.5×10 4 , n = 1.0.

[0097] Real-time adjustment process: When the temperature at the center of the molten pool reaches 1620°C, the distance between the magnet and the arc is automatically adjusted to 18mm (magnetic field enhanced to 0.13T) to strengthen the stirring of the molten pool; when the temperature drops to 1450°C, the spacing returns to 40mm (magnetic field weakened to 0.04T) to extend the solidification feeding time.

[0098] Comparative Example 5

[0099] The difference between Comparative Example 5 and Example 5 is that no magnetic field and infrared control system are applied during the welding process.

[0100] Table 5 shows the comparison of the welding quality of Example 5 and Comparative Example 5 after welding.

[0101] Table 5

[0102]

[0103] As can be seen from the comparison, the heat input during the welding process of the technology of the present invention is lower, the weld forming effect is significantly better than that of the comparative example, the width of the heat affected zone, the porosity and the deformation amount are greatly reduced, and the strength of the welded joint after welding is much greater than that of the traditional welding process.

[0104] From the welding effects of the above 5 examples and 5 comparative examples, it can be seen that the infrared induction feedback type permanent magnet magnetic field assisted TIG welding device and its working method of the present invention significantly improve the welding quality of ultra-thin stainless steel plates, and have outstanding advantages in aspects such as weld formation, preventing burn-through, controlling deformation and improving mechanical properties, fully verifying the innovation and industrial application value of the patented technology. The popularization and application of the present invention will broaden the application scope of TIG welding.

Claims

1. An infrared induction feedback permanent magnet magnetic field assisted TIG welding device, characterized in that: The invention comprises a TIG welding gun (2) placed above a workpiece for performing TIG welding on the workpiece, a welding power source (1) connected to a tungsten pole in the TIG welding gun (2), a permanent magnet group (6) placed above the workpiece, a magnet driving mechanism (7) for driving the permanent magnet group (6), and an infrared temperature detector (5) placed on the side of the workpiece; The driving permanent magnet group (6) and the infrared temperature detector (5) are both connected to a control system (8); the infrared temperature detector (5) is used to detect the arc temperature distribution in real time and feed back the detected arc temperature to the control system (8); the control system (8) is used to compare the arc temperature with a preset threshold value and send a control signal to the magnet driving mechanism (7) according to the comparison result; the magnet driving mechanism (7) is used to adjust the distance between the two permanent magnets in the permanent magnet group (6) and the arc based on the control signal, so as to realize dynamic adjustment of the magnetic field strength.

2. The infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 1 is characterized in that: The workpiece is a stainless steel sheet, and the device is suitable for TIG welding of 0.5-2 mm stainless steel sheets.

3. The infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 1 is characterized in that: When the detected arc temperature exceeds a preset threshold, the magnet drive mechanism (7) reduces the distance between the two permanent magnets in the permanent magnet group (6) and the arc until the magnetic field intensity increases to 0.05-0.3T; when the detected arc temperature is less than the preset threshold, the magnet drive mechanism (7) increases the distance between the two permanent magnets in the permanent magnet group (6) and the arc.

4. The infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 1, characterized in that: A wire feeding mechanism (3) is provided above the workpiece.

5. The infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 1, characterized in that: The TIG welding gun (2) is connected to a gas cylinder (4).

6. The infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 1, characterized in that: The permanent magnet group (6) is a rare earth permanent magnet neodymium iron boron magnet group, and the surface of the rare earth permanent magnet neodymium iron boron magnet group is nickel-plated.

7. A working method of an infrared induction feedback permanent magnet magnetic field assisted TIG welding device, characterized in that: The working method is applied to the infrared induction feedback permanent magnet magnetic field assisted TIG welding device described in claim 1, and the working method comprises: The workpiece is fixed on a water-cooled workpiece table, and the initial distance between two permanent magnets in the permanent magnet group (6) and the electric arc is modulated to a preset value; The infrared temperature threshold T0 of the control system (8) is set to 1400-1600°C, argon protection is started, and the flow rate of the gas cylinder (4) is set to 10-20L / min; Turn on the welding power supply (1), set the current I to 30-80A, connect the tungsten electrode in the TIG welding gun (2) to generate an arc, and start welding; The infrared temperature detector (5) detects the arc temperature in real time and feeds back to the control system (8). The control system (8) calculates the optimal distance between the two permanent magnets in the permanent magnet group (6) and the arc through a built-in adjustment algorithm and sends it to the magnet driving mechanism (7). The magnet driving mechanism (7) adjusts the permanent magnet group (6) according to the calculated optimal distance between the two permanent magnets in the permanent magnet group (6) and the arc. The welding speed v is set to 100-1000mm / min, and the magnetic field strength is inversely proportional to the welding speed.

8. The working method of the infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 7 is characterized in that: The regulation algorithm of the control system (8) satisfies the following relationship: Wherein, d is the distance between the two permanent magnets in the permanent magnet group and the arc; T is the arc temperature detected in real time; T0 is the set reference temperature; K is the proportional coefficient; and n is the exponential term.

9. The working method of the infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 8 is characterized in that: The exponent term n has a value range of 1.2-1.

8.

10. The working method of the infrared induction feedback permanent magnet magnetic field assisted TIG welding device according to claim 7, characterized in that: When the arc temperature T detected in real time by the infrared temperature detector (5) is greater than T0, the magnet driving mechanism (7) reduces the distance between the two permanent magnets in the permanent magnet group (6) and the arc to d=5-15 mm; when T<T0, the magnet driving mechanism (7) increases the distance between the two permanent magnets in the permanent magnet group (6) and the arc to d=20-50 mm.

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