Mechanical rotation longitudinal magnetic head assisted efficient electric arc welding and material adding system

Abstract

The mechanical rotation longitudinal magnetic head assisted efficient electric arc welding and material adding system comprises a double-path pulse excitation power source and a welding gun, the welding gun is sleeved with a rotatable straight cylinder type magnetic head, the straight cylinder type magnetic head is connected with a driving assembly used for driving the straight cylinder type magnetic head to rotate, and two layers of copper windings are arranged outside the magnetic head. The two-way pulse excitation power supply comprises an inner-layer winding and an outer-layer winding, the inner-layer winding and the outer-layer winding are divided through an insulating layer, and I1-way pulse excitation current and I2-way pulse excitation current provided by the two-way pulse excitation power supply are opposite in direction and are connected into the inner-layer winding and the outer-layer winding respectively. According to the system, the penetration rate can be increased, local overheating is reduced, welding seam forming is improved, the welding seam quality is improved, and the effects of refining grains and the like can be achieved.

Description

Technical Field

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

[0002] Welding technology plays a key supporting role in the field of marine ships. Its application runs through the entire process of ship design, manufacturing, and maintenance. The welding processes of high-strength steel, aluminum alloy, and composite materials are continuously optimized. Through automated welding and robot technology, the hull structure strength and corrosion resistance are improved to meet the 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. Improving its welding speed is an important way to improve production efficiency. However, at high welding speeds (v≥1.2m / min), the welding arc will show a dragging phenomenon. When the welding speed is further increased, hump defects will be induced. The generation of these defects seriously reduces the mechanical properties of the joint and becomes a bottleneck for improving welding production efficiency. Currently, using an external magnetic field to improve the GMAW welding process has the advantages of low cost, small volume, and easy operation. Currently, the main measures are: (1) using a longitudinal magnetic field to compress the arc and improve the stability of droplet transfer; (2) using a transverse DC magnetic field to control the welding forward inclination angle and increase the welding speed; (3) using a pulsed composite magnetic field to swing left and right while increasing the welding forward inclination angle, improving the welding speed and the lateral spreading ability of the liquid metal at the same time.

[0003] Adopting longitudinal, transverse, and pulsed composite magnetic fields, etc., can solve common problems such as dragging and insufficient lateral spreading in high-speed welding. However, the above related methods will all cause local concentration of the welding heat distribution, that is, they act in a local area, especially the effect at the solid-liquid interface is weak, and the improvement effect on the microstructure is limited. At the same time, a large magnetic field will cause ionization at the arc edge, weakening the protection effect of the shielding gas, thereby generating defects such as pores. Summary of the Invention

[0004] To solve the deficiencies of the current technology, the present invention combines the existing technology and starts from practical applications to provide a mechanical rotating longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system, which can improve the penetration rate while reducing local overheating, improve the weld formation, enhance the weld quality, and can also play a role in refining grains, etc.

[0005] The technical solution of the present invention is as follows:

[0006] A mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system, including a dual-channel pulsed excitation power supply and a welding torch. A rotatable straight cylindrical magnetic head is sleeved outside the welding torch. The straight cylindrical magnetic head is connected to a driving component for driving its rotation. Two layers of copper windings are arranged outside 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 pulsed excitation current of the I1 path and the pulsed excitation current of the I2 path provided by the dual-channel pulsed excitation power supply are opposite in direction 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 arranged outside the welding torch. An internal annular motion guide rail and four internal annular current guide rails are arranged inside the magnetic head. The internal annular motion guide rail and the external annular motion guide rail cooperate for the rotation guidance of the magnetic head.

[0008] Two of the four external annular current guide rails are respectively connected to the input end and the output end of the pulsed excitation current of the I1 path and the pulsed excitation current of the I2 path. Two of the four internal annular current guide rails are respectively connected to the inner winding and the "(such as in stages T1 and T3)" current guide rails. The four internal annular current guide rails are fitted to transmit the current of the dual-channel pulsed excitation power supply to the inner winding and the outer winding.

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

[0010] Furthermore, during the welding process,

[0011] Let the unit time be T. During the T1 time, the pulsed excitation current of the I1 path is activated, and the pulsed excitation current of the I2 path is not activated. During the T2 time, neither the pulsed excitation current of the I1 path nor the pulsed excitation current of the I2 path is activated. During the T3 time, the pulsed excitation current of the I1 path is not activated, and the pulsed excitation current of the I2 path is activated. During the T4 time, neither the pulsed excitation current of the I1 path nor the pulsed excitation current of the I2 path is activated. The whole action cycle is in the "T1-T2-T3-T4" cycle in sequence.

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

[0013] During the T1 time period, the driving component controls the magnetic head to rotate counterclockwise. The pulsed excitation current of the I1 path is in the activated state, and the pulsed excitation current of the I2 path is in the non-activated state. One end of the magnetic head close to the arc is the N pole, and the end far from the arc is the S pole.

[0014] During time period T2, the drive component controls the head to rotate counterclockwise. The pulse excitation current of path I1 is in an inactive state, the pulse excitation current of path I2 is in an inactive state, and there is no polarity at both ends of the head.

[0015] During time period T3, the drive component controls the head to rotate clockwise. The pulse excitation current of path I1 is in an inactive state, the pulse excitation current of path I2 is in an active state. The end of the head close to the arc is the S pole, and the end far from the arc is the N pole.

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

[0017] Advantages of the present invention:

[0018] 1. In the present invention, the magnetic field radially pulse-compresses the arc, enabling the arc to undergo the changes of "compression - expansion - compression - expansion" within one cycle. This can increase the penetration depth, improve the penetration rate, reduce local overheating while improving the weld formation, and enhance the weld quality.

[0019] 2. In the present invention, the mechanical rotation of the magnetic field induces an induced current in the molten pool. Affected by the magnetic field, the induced current generates an electromagnetic force perpendicular to the induced current, forming a concentric circular distributed annular eddy current in the molten pool. The eddy current moves from the center of the molten pool to the edge, breaking the static stratification of the molten pool, reducing segregation while breaking dendrites, and playing a role in refining grains.

[0020] 3. The present invention adopts a double collision mechanism. The change in the direction of the bidirectional eddy current will cause the eddy currents to collide, forming a shear force to break dendrites. The bidirectional eddy currents diffusing from the center to the edge of the molten pool will collide with the turbulence caused by the arc force during arc contraction. The bidirectional eddy currents and arc turbulence form a high shear zone to break 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 head of the present invention.

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

[0024] Figure 4 It is a schematic diagram of the internal guide rail structure of the head of the present invention.

[0025] Figure 5 It is a schematic diagram of the arc action mechanism of the present invention.

[0026] Figure 6This is a schematic diagram of the working mechanism of the liquid molten pool of the present invention.

[0027] Reference numerals shown in the drawings:

[0028] 1. Magnetic head; 2. Welding torch; 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. Power terminal current interface; 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. Magnetic head terminal current interface. Detailed implementation manners

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

[0030] This embodiment provides a mechanical rotation longitudinal magnetic head assisted high-efficiency arc welding and additive manufacturing system.

[0031] The main structure of the system is shown in Figures 1-4 The figure. The system mainly includes a dual-channel pulse excitation power supply 3, an alternating motor 4, and an external straight cylindrical rotatable magnetic head 1. The magnetic head 1 is sleeved outside the welding torch 2. The dual-channel pulse excitation power supply 3 can generate two excitation currents, namely the I1-channel pulse excitation current and the I2-channel pulse excitation current.

[0032] As Figure 2 shown in the figure, two layers of copper windings are wound outside the magnetic head 1, namely the inner winding 7 and the outer winding 9. The number of turns of the copper coils in the windings can be adjusted according to the use requirements. The inner winding 7 and the outer winding 9 are separated by an insulation layer 8 (insulation tape). The I1-channel pulse excitation current is connected to the inner winding 7, and the I2-channel pulse excitation current is connected to the outer winding 9. The current directions of the pulse excitation currents I1 and I2 are opposite, and this structure can provide a longitudinal rotational electromagnetic force.

[0033] In this embodiment, the magnetic head 1 can rotate forward and backward, and it is controlled by the alternating motor 4. The alternating motor 4 is fixed at a suitable position of the welding torch 2, and it drives the magnetic head 1 to rotate through the gear set 5. Specifically, the output shaft of the alternating motor 4 is connected to a gear, and a ring of gears is arranged on the outer circle of the magnetic head 1, and the gears mesh with each other to form the gear set 5. The rotation direction and rotation speed of the magnetic head 1 are realized by controlling the alternating motor 4 through the alternating motor controller 6.

[0034] Considering that the magnetic head 1 rotates relative to the welding torch 2, in order to ensure the stable transmission of the exciting current to the magnetic head 1, a simple and reliable guide rail structure is designed in this embodiment. Specifically, an external annular motion guide rail 11 and four external annular current guide rails 12 are provided outside the welding torch 2. The four external annular current guide rails 12 are respectively connected to a power supply terminal current interface 10. An internal annular motion guide rail 13 and four internal annular current guide rails 14 are provided inside the magnetic head 1. The four internal annular current guide rails 14 are respectively connected to a magnetic head terminal current interface 15. After the magnetic head 1 is installed, its internal annular motion guide rail 13 is mutually engaged with the external annular motion guide rail 11, which can be used for the rotation guidance of the magnetic head 1, and the four internal annular current guide rails 14 are mutually engaged with the four external annular current guide rails 12 to realize the transmission of current.

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

[0036] Two of the four external annular current guide rails 12 are respectively connected to the input terminal and output terminal of the I1 path pulse exciting current and the I2 path pulse exciting current, and two of the four internal annular current guide rails 14 are respectively connected to the inner winding 7 and the outer winding 9. The engagement of the external annular current guide rail 12 and the internal annular current guide rail 14 transmits the current of the dual-path pulse exciting power supply 3 to the inner winding 7 and the outer winding 9.

[0037] In this system, let the unit time be T. Within the T1 time period, the I1 path exciting pulse current is activated and the I2 path exciting pulse current is not activated; within the T2 time period, neither the I1 nor the I2 path exciting current is activated; within the T3 time period, the I1 path pulse exciting current is not activated and the I2 path pulse exciting current is activated; within the T4 time period, neither the I1 nor the I2 path exciting current is activated. The entire action cycle is in the order of "T1 - T2 - T3 - T4" cycle.

[0038] Furthermore, within the cycle period of T1 - T4 time periods, the relationship between the I1 path pulse exciting current, the I2 path pulse exciting current and the magnetic pole matching is as follows:

[0039] During the T1 time 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 path pulse exciting current is in the activated state, the I2 path pulse exciting current is in the non-activated state, the end of the magnetic head 1 close to the arc is the N pole, and the end far from the arc is the S pole;

[0040] During the T2 time 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 path pulsed excitation current is in an inactive state, the I2 path pulsed excitation current is in an inactive state, and there is no polarity at both ends of the magnetic head 1.

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

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

[0043] The above excitation method of this system has the following principles and effects.

[0044] 1. Periodically compress the arc

[0045] The electromagnetic force formula is:

[0046]

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

[0048] According to the formula, it can be obtained that the speed of the charged particle and the electromagnetic force are positively correlated. The greater the speed of the magnetic field rotation caused by the motor, the greater the electromagnetic force on the arc and the molten pool. As Figure 5 shown, a closed magnetic induction line is generated at the end of the magnetic head 1 close to the arc. According to the left-hand rule, the arc is subjected to a radial compression force, resulting in the rotation and compression of the arc. The mechanical rotation of the magnetic field causes the magnetic induction line to cut the arc. Among them, the arc is a charged conductor. In this process, it is equivalent that the magnetic field remains unchanged and the arc cuts the magnetic field in a rotating form. Therefore, according to the electromagnetic induction principle, using the right-hand rule, a current as shown in Figure 5The annular unidirectional induced current as shown. The induced current is affected by the magnetic field to generate an electromagnetic force perpendicular to the induced current, and induced eddy currents are generated in the arc. The direction of the eddy current is affected by the magnetic field and the rotation direction, and the existence of the eddy current further compresses the arc. The axial rotating magnetic field (such as in the T1 and T3 stages) compresses the arc, inhibits diffusion, and reduces spatter. The change of the magnetic pole causes the compression direction to change periodically, avoiding local overheating while maintaining the arc stiffness. In the T2 / T4 stages (without magnetic field), the arc naturally diffuses and dissipates heat to avoid overheating. The combination of the rotating magnetic field and the pulse can achieve an alternating heat input of "concentration - diffusion". Since the movement of the arc lags behind the change of the magnetic field, the introduction of the T2 / T4 stages (without magnetic field) avoids the arc oscillation that occurs during the magnetic pole switching, and the arc shape is more stable.

[0049] 2. Eddy currents in the molten pool

[0050] The mechanical rotation of the magnetic field causes the magnetic induction lines to cut the molten pool, where the molten pool is a charged conductor. In this process, it is equivalent to the magnetic field remaining unchanged and the molten pool cutting the magnetic field in a rotating form. Therefore, according to the principle of electromagnetic induction and using the right - hand rule, an annular unidirectional induced current as shown Figure 6 is generated in the molten pool. The induced current is affected by the magnetic field to generate an electromagnetic force perpendicular to the induced current. Therefore, under the action of the molten droplet, an annular eddy current that diffuses from the center of the molten pool to the edge is generated in the molten pool. Due to the change of the magnetic pole at one end close to the arc, the direction of the induced current in the molten pool is opposite, and the direction of the Lorentz force received by the induced current is opposite. Therefore, a bidirectional eddy current that diffuses from the center of the molten pool to the edge and collides with each other is formed in the liquid molten pool.

[0051] 3. Grain refinement mechanism

[0052] Firstly, the change in the direction of the bidirectional eddy current will cause the eddy currents to collide, forming a shear force that breaks dendrites. Secondly, since the T1 and T3 stages are the radial compression stages of the arc, the bidirectional eddy currents that diffuse from the center of the molten pool to the edge will collide with the turbulence caused by the arc force when the arc contracts. The bidirectional eddy currents and the arc turbulence form a high - shear zone, which also breaks the primary dendrites in the molten pool. The micro - zone turbulence generated by the eddy current collision destroys the temperature gradient, and the center - edge diffusion eddy current accelerates the radial heat transfer, reducing the temperature gradient of the molten pool and increasing the proportion of the equiaxed crystal zone. The eddy current that diffuses from the center to the edge pushes the bubbles to migrate to the edge of the molten pool, and together with the pressure fluctuations generated by the periodic arc compression, promotes the rapid escape of pores. At the same time, the bidirectional eddy currents form a centrifugal force field, and the density difference drives the oxides / inclusions to enrich on the surface of the molten pool. The synergistic effect of the periodic compressed arc and the bidirectional eddy currents makes the surface tension gradient of the molten pool tend to be balanced, and the forming quality of the weld surface is improved.

Claims

1. A mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system, comprising a dual-channel pulsed excitation power supply and a welding torch, characterized in that, A rotatable straight - tube - type magnetic head is sleeved outside the welding torch. The straight - tube - type magnetic head is connected to a driving assembly for driving its rotation. Two layers of copper windings are arranged outside the magnetic head, namely an inner - layer winding and an outer - layer winding. The inner - layer winding and the outer - layer winding are separated by an insulating layer. The I1 - path pulsed exciting current and the I2 - path pulsed exciting current provided by a dual - path pulsed exciting power supply have opposite directions and are respectively connected to the inner - layer winding and the outer - layer winding.

2. The mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system according to claim 1, wherein An external annular motion guide rail and four external annular current guide rails are arranged outside the welding torch. An internal annular motion guide rail and four internal annular current guide rails are arranged inside the magnetic head. The internal annular motion guide rail and the external annular motion guide rail cooperate for guiding the rotation of the magnetic head; Two of the four external annular current guide rails are respectively connected to the input end and the output end of the I1 - path pulsed exciting current and the I2 - path pulsed exciting current. Two of the four internal annular current guide rails are respectively connected to the inner - layer winding and the outer - layer winding. The four external annular current guide rails and the four internal annular current guide rails are fitted together to transmit the current of the dual - path pulsed exciting power supply to the inner - layer winding and the outer - layer winding.

3. The mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system according to claim 1, wherein The driving assembly includes an alternating motor and a gear set. The alternating motor is fixed on the welding torch. The alternating motor drives the magnetic head to rotate forward and backward through the gear set. The rotation direction and speed of the magnetic head are controlled by an alternating - motor controller.

4. The mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system according to any one of claims 1-3, characterized in that, During the welding process, Let the unit time be T. Within the T1 time period, the I1 - path pulsed exciting current is activated, and the I2 - path pulsed exciting current is not activated; Within the T2 time period, neither the I1 - path pulsed exciting current nor the I2 - path pulsed exciting current is activated; Within the T3 time period, the I1 - path pulsed exciting current is not activated, and the I2 - path pulsed exciting current is activated; within the T4 time period, neither the I1 - path pulsed exciting current nor the I2 - path pulsed exciting current is activated. The whole action cycle is in the order of "T1 - T2 - T3 - T4" cycle.

5. The mechanical rotation longitudinal magnetic head-assisted high-efficiency arc welding and additive manufacturing system according to claim 4, wherein Within the cycle period of T1 - T4 time periods, the matching relationship between the I1 - path pulsed exciting current, the I2 - path pulsed exciting current and the magnetic head is as follows: During the T1 time period, the driving assembly controls the magnetic head to rotate counter - clockwise. The I1 - path pulsed exciting current is in the activated state, and the I2 - path pulsed exciting current is in the non - activated state. The end of the magnetic head close to the arc is the N - pole, and the end far from the arc is the S - pole; During the T2 time period, the driving assembly controls the magnetic head to rotate counter - clockwise. The I1 - path pulsed exciting current is in the non - activated state, and the I2 - path pulsed exciting current is in the non - activated state. There is no polarity at both ends of the magnetic head; During the T3 time period, the driving assembly controls the magnetic head to rotate clockwise. The I1 - path pulsed exciting current is in the non - activated state, and the I2 - path pulsed exciting current is in the activated state. The end of the magnetic head close to the arc is the S - pole, and the end far from the arc is the N - pole; During the T4 time period, the driving assembly controls the magnetic head to rotate clockwise. The I1 - path pulsed exciting current is in the non - activated state, and the I2 - path pulsed exciting current is in the non - activated state. There is no polarity at both ends of the magnetic head.

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