A mechanically rotating longitudinal magnetic head-assisted high-efficiency arc welding and additive system

Abstract

The present invention provides a high-efficiency arc welding and additive system assisted by a mechanically rotating longitudinal magnetic head. The system comprises a dual-channel pulse excitation power supply and a welding gun. The welding gun is externally mounted with a rotatable straight-cylinder magnetic head connected to a drive assembly for its rotation. Two layers of copper windings are externally disposed on the magnetic head: an inner winding and an outer winding, separated by an insulating layer. The dual-channel pulse excitation power supply provides pulse excitation currents I1 and I2 in opposite directions, connected to the inner and outer windings, respectively. This system can improve penetration while reducing local overheating, improving weld formation and quality, and can also refine grain size.

Description

Technical Field

[0001] The present invention mainly relates to the technical fields related to welding and additive manufacturing, and specifically to a high-efficiency arc welding and additive manufacturing system assisted by a mechanically rotating longitudinal magnetic head. Background Art

[0002] Welding technology plays a key supporting role in the marine vessel sector, with applications throughout the entire process of ship design, manufacturing, and maintenance. Welding processes for high-strength steel, aluminum alloys, and composite materials are continuously being optimized. Automated welding and robotics are enhancing the structural strength and corrosion resistance of ship hulls to meet reliability requirements in extreme environments such as deep-sea high pressure and salt spray corrosion. Currently, gas metal arc welding (GMAW) dominates the application of various welding technologies, and increasing its welding speed is a key approach to improving production efficiency. However, at high welding speeds (v ≥ 1.2 m / min), the welding arc can drag. Further increases in welding speed can also induce hump defects, which severely reduce the mechanical properties of the joint and become a bottleneck in improving welding production efficiency. Currently, improving the GMAW welding process using an applied magnetic field offers advantages such as low cost, compact size, and ease of operation. At present, the main methods are: (1) longitudinal magnetic field compresses the arc to improve the stability of droplet transfer; (2) transverse DC magnetic field controls the welding forward tilt angle to increase welding speed; (3) pulse composite magnetic field increases the welding forward tilt angle while swinging left and right, thereby increasing welding speed and improving the lateral spreading ability of liquid metal.

[0003] Using longitudinal, transverse, and pulsed composite magnetic fields can address common issues with high-speed welding, such as drag and insufficient lateral spread. However, all of these methods result in localized heat distribution, affecting a specific area. This effect is particularly weak at the solid-liquid interface, limiting microstructural improvement. Furthermore, larger magnetic fields can cause arc edge ionization, weakening the shielding gas's effectiveness and leading to defects such as porosity. Summary of the Invention

[0004] To address the shortcomings of current technology, the present invention combines existing technologies and, based on practical applications, provides a mechanically rotating longitudinal magnetic head-assisted high-efficiency arc welding and additive system, which can increase the penetration rate while reducing local overheating, improve weld formation, enhance weld quality, and play a role in grain refinement.

[0005] The technical solutions of the present invention are as follows:

[0006] A mechanically rotating longitudinal magnetic head-assisted high-efficiency arc welding and additive system includes a dual-path pulse excitation power supply and a welding gun. A rotatable straight-cylinder magnetic head is mounted on the outside of the welding gun, and the straight-cylinder magnetic head is connected to a drive assembly for driving its rotation. Two layers of copper windings are arranged on the outside of the magnetic head, namely an inner winding and an outer winding, and the inner winding and the outer winding are separated by an insulating layer. The I1 pulse excitation current and the I2 pulse excitation current provided by the dual-path pulse excitation power supply are in opposite directions and are respectively connected to the inner winding and the outer winding.

[0007] Furthermore, an external annular motion guide rail and four external annular current guide rails are provided on the outside of the welding gun, and an internal annular motion guide rail and four internal annular current guide rails are provided on the inside of the magnetic head, and the internal annular motion guide rail and the external annular motion guide rail cooperate to guide the rotation of the magnetic head;

[0008] The four external ring current rails are connected to the input and output ends of the I1 pulse excitation current and the I2 pulse excitation current in pairs, respectively. The four built-in ring current rails are connected to the inner winding and the "(such as T1 and T3 stages)" current rail in pairs, respectively. The four built-in ring current rails are embedded to transmit the current of the dual-path pulse excitation power supply to the inner winding and the outer winding.

[0009] Furthermore, the driving assembly includes an alternating motor and a gear set. The alternating motor is fixed to the welding gun. The alternating motor drives the magnetic head to rotate forward and reverse through the gear set. The rotation direction and speed of the magnetic head are controlled by the alternating motor controller.

[0010] Furthermore, during the welding process,

[0011] Assume that the unit time is T. During T1, the I1 pulse excitation current is activated and the I2 pulse excitation current is not activated; during T2, both the I1 pulse excitation current and the I2 pulse excitation current are not activated; during T3, the I1 pulse excitation current is not activated and the I2 pulse excitation current is activated; during T4, both the I1 pulse excitation current and the I2 pulse excitation current are not activated. The entire action cycle is a "T1-T2-T3-T4" cycle.

[0012] Furthermore, in the cycle period T1-T4, the matching relationship between the I1 pulse excitation current, the I2 pulse excitation current and the magnetic head is as follows:

[0013] During the T1 period, the drive component controls the magnetic head to rotate counterclockwise. The I1 pulse excitation current is active, and the I2 pulse excitation current is inactive. The end of the magnetic head close to the arc is the N pole, and the end away from the arc is the S pole.

[0014] During the T2 period, the drive component controls the magnetic head to rotate counterclockwise, the I1 pulse excitation current is inactive, the I2 pulse excitation current is inactive, and there is no polarity at both ends of the magnetic head;

[0015] During the T3 period, the drive component controls the magnetic head to rotate clockwise, the I1 pulse excitation current is inactive, the I2 pulse excitation current is active, the end of the magnetic head close to the arc is the S pole, and the end away from the arc is the N pole;

[0016] During the T4 period, the drive component controls the magnetic head to rotate clockwise, the I1 pulse excitation current is in an inactive state, the I2 pulse excitation current is in an inactive state, and there is no polarity at both ends of the magnetic head.

[0017] Beneficial effects of the present invention:

[0018] 1. In the present invention, the magnetic field compresses the arc in a radial pulsed manner, so that the arc can achieve a "compression-expansion-compression-expansion" change within one cycle, which can increase the penetration depth, improve the penetration rate, reduce local overheating, improve the weld formation, and enhance the weld quality.

[0019] 2. In this invention, the mechanical rotation of the magnetic field induces an induced current within the molten pool. This current, influenced by the magnetic field, generates an electromagnetic force perpendicular to the induced current, forming concentrically distributed annular eddy currents within the molten pool. These eddy currents move from the center to the edges of the molten pool, disrupting static stratification, reducing segregation, and breaking up dendrites, resulting in grain refinement.

[0020] 3. The present invention adopts a double collision mechanism. The change in the direction of the bidirectional eddy current will cause the eddy current to collide, forming shear force and breaking the dendrites. The bidirectional eddy current spreading from the center to the edge of the molten pool will collide with the turbulence caused by the arc force when the arc contracts. The bidirectional eddy current and the arc turbulence form a high shear zone, which breaks the primary dendrites in the molten pool. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the structure of the straight-cylinder magnetic head of the present invention.

[0023] Figure 3 It is a schematic diagram of the external guide rail structure of the welding gun of the present invention.

[0024] Figure 4 Schematic diagram of the internal guide rail structure of the magnetic head of the present invention.

[0025] Figure 5 Schematic diagram of the arc action mechanism of the present invention.

[0026] Figure 6Schematic diagram of the action mechanism of the liquid molten pool of the present invention.

[0027] Reference numerals shown in the accompanying drawings:

[0028] 1. Magnetic head; 2. Welding gun; 3. Dual-channel pulse excitation power supply; 4. Alternating motor; 5. Gear set; 6. Alternating motor controller; 7. Inner winding; 8. Insulation layer; 9. Outer winding; 10. Current interface at the power supply end; 11. External annular motion guide rail; 12. External annular current guide rail; 13. Internal annular motion guide rail; 14. Internal annular current guide rail; 15. Current interface at the magnetic head end. DETAILED DESCRIPTION

[0029] The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the present application.

[0030] This embodiment provides a high-efficiency arc welding and material addition system assisted by a mechanically rotating longitudinal magnetic head.

[0031] The main structural reference of the system Figures 1-4 The system mainly includes a dual-channel pulse excitation power supply 3, an alternating current motor 4, and an external straight-cylinder rotatable magnetic head 1. The magnetic head 1 is mounted on the outside of the welding gun 2. The dual-channel pulse excitation power supply 3 can generate two excitation currents, namely, the pulse excitation current I1 and the pulse excitation current I2.

[0032] like Figure 2 As shown, the exterior of the magnetic head 1 is wrapped with two layers of copper windings: an inner winding 7 and an outer winding 9. The number of copper turns in each winding can be adjusted according to application requirements. The inner and outer windings 7 and 9 are separated by an insulating layer 8 (insulating tape). A pulsed excitation current, I1, is connected to the inner winding 7, and a pulsed excitation current, I2, is connected to the outer winding 9. The pulsed excitation currents I1 and I2 flow in opposite directions. This structure provides a longitudinal rotational electromagnetic force.

[0033] In this embodiment, the magnetic head 1 is capable of forward and reverse rotation, controlled by an alternating motor 4. The alternating motor 4 is secured to a suitable position on the welding torch 2 and drives the magnetic head 1 to rotate via a gear set 5. Specifically, the output shaft of the alternating motor 4 is connected to a gear, and a ring of gears is provided on the outer ring of the magnetic head 1. The gears mesh with each other to form the gear set 5. The rotation direction and speed of the magnetic head 1 are controlled by the alternating motor controller 6, which controls the alternating motor 4.

[0034] Considering that the magnetic head 1 rotates relative to the welding torch 2, a simple and reliable guide rail structure is designed in this embodiment to ensure stable transmission of the excitation current to the magnetic head 1. Specifically, an external annular motion guide rail 11 and four external annular current guide rails 12 are provided on the outside of the welding torch 2. Each of the four external annular current guide rails 12 is connected to a power supply end current interface 10. An internal annular motion guide rail 13 and four internal annular current guide rails 14 are provided on the inside of the magnetic head 1. Each of the four internal annular current guide rails 14 is connected to a magnetic head end current interface 15. After the magnetic head 1 is installed, the internal annular motion guide rail 13 and the external annular motion guide rail 11 interlock with each other, serving to guide the rotation of the magnetic head 1. Furthermore, the four internal annular current guide rails 14 interlock with the four external annular current guide rails 12 to achieve current transmission.

[0035] The input and output ends of the I1 pulse excitation current and I2 pulse excitation current of the dual-path pulse excitation power supply 3 are respectively connected to the corresponding power supply end current interface 10, so that the current at the power supply end can be transmitted to the four external ring current rails 12 and then transmitted to the head end current interface 15 through the four internal ring current rails 14. The four head end current interfaces 15 are respectively connected to the corresponding inner winding 7 and outer winding 9, so that the current at the power supply end can be smoothly transmitted to the inner winding 7 and the outer winding 9 when the magnetic head 1 rotates.

[0036] The four external ring current rails 12 are connected to the input and output ends of the I1 pulse excitation current and the I2 pulse excitation current in pairs, respectively. The four internal ring current rails 14 are connected to the inner winding 7 and the outer winding 9 in pairs. The external ring current rails 12 and the internal ring current rails 14 are embedded in each other to transmit the current of the dual-path pulse excitation power supply 3 to the inner winding 7 and the outer winding 9.

[0037] In this system, assuming the unit time is T, during T1, the excitation pulse current I1 is active, while the excitation pulse current I2 is inactive; during T2, both the excitation currents I1 and I2 are inactive; during T3, the pulse excitation current I1 is inactive, while the pulse excitation current I2 is active; and during T4, both the excitation currents I1 and I2 are inactive. The entire action cycle is a "T1-T2-T3-T4" cycle.

[0038] Furthermore, during the cycle period T1-T4, the matching relationship between the I1 pulse excitation current, the I2 pulse excitation current and the magnetic pole is as follows:

[0039] During the T1 period, the gear connected to the alternating current motor 4 rotates clockwise. Through the gear transmission structure, the magnetic head 1 rotates counterclockwise. The I1 pulse excitation current is in an active state, and the I2 pulse excitation current is in an inactive state. The end of the magnetic head 1 close to the arc is the N pole, and the end away from the arc is the S pole.

[0040] During time period T2, the gear connected to the alternating motor 4 rotates clockwise, and the magnetic head 1 rotates counterclockwise through the gear transmission structure. The I1 pulse excitation current is inactive, the I2 pulse excitation current is inactive, and there is no polarity at both ends of the magnetic head 1.

[0041] During the T3 period, the gear connected to the alternating motor 4 rotates counterclockwise. Through the gear transmission structure, the magnetic head 1 rotates clockwise. The I1 pulse excitation current is inactive, and the I2 pulse excitation current is active. The end of the magnetic head 1 close to the arc is the S pole, and the end away from the arc is the N pole.

[0042] During the T4 period, the gear connected to the alternating motor 4 rotates counterclockwise. Through the gear transmission structure, the magnetic head 1 rotates clockwise. The I1 pulse excitation current is in an inactive state, the I2 pulse excitation current is in an inactive state, and there is no polarity at both ends of the magnetic head.

[0043] The principles and effects of the above-mentioned excitation method of this system are as follows.

[0044] 1. Periodic compression arc

[0045] The electromagnetic force formula is:

[0046]

[0047] in: is the electromagnetic force; is the amount of charge in the arc; is the speed of the charged particle relative to the magnetic field; is the magnetic induction intensity.

[0048] According to the formula, the speed of charged particles is and electromagnetic force The greater the speed at which the motor causes the magnetic field to rotate, the greater the electromagnetic force on the arc and the molten pool. Figure 5 As shown, the magnetic head 1 generates closed magnetic flux lines near one end of the arc. According to the left-hand rule, the arc is subjected to radial compression, causing the arc to rotate and compress. The mechanical rotation of the magnetic field causes the magnetic flux lines to cut the arc, where the arc is a charged conductor. In this process, the magnetic field remains unchanged, and the arc cuts the magnetic field in a rotating form. Therefore, according to the principle of electromagnetic induction, using the right-hand rule, the following is generated in the molten pool: Figure 5The circular unidirectional induced current shown. The induced current, influenced by the magnetic field, generates an electromagnetic force perpendicular to the induced current, generating eddy currents in the arc. The direction of the eddy currents is affected by the magnetic field and the direction of rotation, and their presence further compresses the arc. An axially rotating magnetic field (such as in phases T1 and T3) compresses the arc, suppressing diffusion and reducing spatter. The magnetic pole changes periodically alter the compression direction, preventing localized overheating while maintaining arc stiffness. During the T2 / T4 phase (no magnetic field), the arc naturally diffuses heat to prevent overheating. The combination of a rotating magnetic field and pulses achieves alternating "concentrated-diffused" heat input. Because the arc's motion lags behind the magnetic field changes, the introduction of the T2 / T4 phase (no magnetic field) avoids arc oscillations that occur during magnetic pole switching, resulting in a more stable arc morphology.

[0049] 2. Molten pool vortex

[0050] The mechanical rotation of the magnetic field causes the magnetic flux lines to cut the molten pool, where the molten pool is a charged conductor. In this process, the magnetic field remains unchanged, and the molten pool cuts the magnetic field in a rotating form. Therefore, according to the principle of electromagnetic induction, using the right-hand rule, the following is generated in the molten pool: Figure 6 The circular unidirectional induced current shown in the figure. The induced current, influenced by the magnetic field, generates an electromagnetic force perpendicular to the induced current. Consequently, under the action of the droplet, a circular eddy current is generated in the molten pool, extending from the center to the edge. Due to the change in magnetic polarity near the end of the arc, the direction of the induced current in the molten pool is opposite, and the Lorentz force acting on the induced current is also opposite. Consequently, bidirectional eddy currents form in the liquid molten pool, extending from the center to the edge and colliding with each other.

[0051] 3. Grain refinement mechanism

[0052] First, the change in direction of the bidirectional vortexes causes them to collide, generating shear forces that break up dendrites. Second, because stages T1 and T3 are radial arc compression stages, the bidirectional vortexes that diffuse from the center of the molten pool to the edges collide with the turbulence caused by the arc force during arc contraction. The bidirectional vortexes and arc turbulence form a high shear zone, similarly breaking up primary dendrites within the molten pool. The microturbulence generated by the vortex collisions disrupts the temperature gradient, and the center-to-edge diffusion vortex accelerates radial heat transfer, reducing the molten pool temperature gradient and increasing the proportion of equiaxed crystals. The vortexes that diffuse from the center to the edges propel bubbles toward the molten pool edge, and combined with the pressure fluctuations generated by the periodic arc compression, they promote the rapid escape of pores. Simultaneously, the bidirectional vortexes create a centrifugal force field, and density differences drive oxides and inclusions toward the molten pool surface. The synergistic effect of the periodic arc compression and the bidirectional vortexes balances the surface tension gradient of the molten pool, improving the weld surface quality.

Claims

1. A mechanically rotating longitudinal magnetic head assisted high-efficiency arc welding and material addition system, comprising a dual-path pulse excitation power supply and a welding gun, characterized in that: The welding gun is provided with a rotatable straight-cylinder magnetic head on the outside, which is connected to a driving assembly for driving the rotation thereof. Two layers of copper windings are provided on the outside of the magnetic head, namely an inner winding and an outer winding. The inner winding and the outer winding are separated by an insulating layer. The I1-way pulse excitation current and the I2-way pulse excitation current provided by the dual-path pulse excitation power supply are in opposite directions and are connected to the inner winding and the outer winding respectively. An external annular motion guide rail and four external annular current guide rails are provided on the outside of the welding gun, and an internal annular motion guide rail and four internal annular current guide rails are provided on the inside of the magnetic head. The internal annular motion guide rail and the external annular motion guide rail cooperate to guide the rotation of the magnetic head. The four external ring current rails are connected to the input and output ends of the I1 pulse excitation current and the I2 pulse excitation current in pairs, respectively. The four internal ring current rails are connected to the inner winding and the outer winding in pairs. The four external ring current rails and the four internal ring current rails are embedded in order to transmit the current of the dual-path pulse excitation power supply to the inner winding and the outer winding.

2. The mechanically rotating longitudinal magnetic head assisted high-efficiency arc welding and material addition system according to claim 1, characterized in that: The driving assembly includes an alternating motor and a gear set. The alternating motor is fixed to the welding gun. The alternating motor drives the magnetic head to rotate forward and reverse through the gear set. The rotation direction and speed of the magnetic head are controlled by the alternating motor controller.

3. The mechanically rotating longitudinal magnetic head-assisted high-efficiency arc welding and additive system according to any one of claims 1-2, characterized in that: During welding, Assume that the unit time is T. During T1, the pulse excitation current of I1 is activated, and the pulse excitation current of I2 is not activated. During T2, the I1 pulse excitation current and the I2 pulse excitation current are both inactive. During T3, the I1 pulse excitation current is inactive, and the I2 pulse excitation current is active; during T4, both the I1 pulse excitation current and the I2 pulse excitation current are inactive. The entire action cycle is a "T1-T2-T3-T4" cycle.

4. The mechanically rotating longitudinal magnetic head assisted high-efficiency arc welding and material addition system according to claim 3, characterized in that: During the cycle period T1-T4, the matching relationship between the I1 pulse excitation current, the I2 pulse excitation current and the magnetic head is as follows: During the T1 period, the drive component controls the magnetic head to rotate counterclockwise. The I1 pulse excitation current is active, and the I2 pulse excitation current is inactive. The end of the magnetic head close to the arc is the N pole, and the end away from the arc is the S pole. During the T2 period, the drive component controls the magnetic head to rotate counterclockwise, the I1 pulse excitation current is inactive, the I2 pulse excitation current is inactive, and there is no polarity at both ends of the magnetic head; During the T3 period, the drive component controls the magnetic head to rotate clockwise, the I1 pulse excitation current is inactive, the I2 pulse excitation current is active, the end of the magnetic head close to the arc is the S pole, and the end away from the arc is the N pole; During the T4 period, the drive component controls the magnetic head to rotate clockwise, the I1 pulse excitation current is in an inactive state, the I2 pulse excitation current is in an inactive state, and there is no polarity at both ends of the magnetic head.

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