A method and apparatus for non-steady-state ultrasonic standing wave assisted control of fusion welding

Abstract

This invention discloses a method for unsteady-state ultrasonic standing wave-assisted control of fusion welding. It utilizes dual ultrasonic transducers to perform dual-wave interference, forming an ultrasonic standing wave. This ultrasonic standing wave is introduced into the fusion welding process, and its action on the welding area allows for real-time control of the microstructure and properties of different parts of the weld joint. This forms a unsteady-state ultrasonic standing wave with controlled directional movement of the wave packet nodes, which is then used to regulate the microstructure and properties of the weld joint. This invention enables control over the direction and speed of movement of the unsteady-state ultrasonic standing wave wave packet nodes, allowing for regional control of the microstructure and properties of different parts of the weld joint, resulting in a more uniform joint composition and microstructure. It can solve problems such as undercut, burn-through, high residual stress, severe deformation, and columnar crystals that reduce joint performance during the welding of thin materials or fine wires, refining grains and improving joint performance. It can achieve controllable connections from the centimeter scale to the micrometer scale.

Description

Technical Field

[0001] This invention relates to a method and apparatus for unsteady-state ultrasonic standing wave-assisted control of fusion welding, belonging to the field of fusion welding technology. Background Technology

[0002] Size effects have a significant impact on material properties. In particular, when the size of a material is reduced to a few micrometers to tens of micrometers, its optical, electrical, magnetic, thermal, and mechanical properties may undergo abrupt changes, giving it a wider range of applications.

[0003] When conventional fusion welding techniques are used to weld thin materials or fine wires, defects such as undercut and burn-through are easily produced. Furthermore, due to the high cooling rate after welding, the joint has a large residual stress, which leads to severe deformation and performance deterioration, thus limiting the application of these fusion welding techniques in micro-nano connections.

[0004] In the melting and welding of thin materials or fine wires, the temperature of the molten pool can instantly reach thousands of degrees, while the metal surrounding the molten pool remains at room temperature. This huge temperature gradient causes columnar crystals to form near the joint, resulting in an uneven joint structure. For micro- and nano-materials with dimensions of only tens or a few micrometers, the localized columnar crystals make the joint extremely prone to breakage.

[0005] To achieve high-quality welding of thin materials and fine wires, there is an urgent need to improve conventional fusion welding techniques. While many experts have researched ultrasonic traveling wave-assisted fusion welding technology—which applies ultrasound to the fusion welding process—it can, to some extent, control the stress and microstructure of the joint. However, it cannot achieve controllable regulation of the molten pool metal transport. In particular, there are currently no reports on controllable micro / nano-joining technology using standing wave-assisted fusion welding. Some reports utilize the energy potential well of ultrasonic standing wave nodes to control the weld point position, leveraging the physical principle that the steady-state ultrasonic standing wave packet nodes are fixed. This differs significantly from the unsteady standing wave used in this invention and lacks the controllable directional movement of the wave packet nodes used in this invention to regulate the molten pool metal transport behavior. Furthermore, it lacks the ability of this invention to regulate the microstructure and properties of different parts of the welded joint in a sectional manner. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for unsteady-state ultrasonic standing wave assisted control fusion welding, which solves the problems of defects such as undercut and burn-through that are easy to occur during the welding of thin plates and fine wires, the phenomenon of large residual stress and severe deformation after welding, and the formation of columnar crystals in the weld that lead to reduced joint performance, thereby improving the overall performance of the welded joint.

[0007] This invention is implemented as follows:

[0008] A method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding includes the following steps:

[0009] S01. Using dual ultrasonic transducers, dual-wave interference is performed to form an ultrasonic standing wave;

[0010] S02. Introducing ultrasonic standing waves into the fusion welding process, by applying ultrasonic standing waves to the welding area, the microstructure and properties of various parts of the welded joint can be controlled in real time.

[0011] S03. By adjusting the parameters of the dual-wave interference, an unsteady ultrasonic standing wave with energy-saving and controlled directional movement of the wave packet is formed. The unsteady standing wave is used to regulate the microstructure and properties of the welded joint.

[0012] The above-mentioned method for unsteady ultrasonic standing wave-assisted controlled fusion welding includes laser welding, electron beam welding, or arc welding.

[0013] The aforementioned method for non-steady-state ultrasonic standing wave assisted control fusion welding involves a non-steady-state ultrasonic standing wave formed by the superposition of two ultrasonic waves with unequal frequencies. Specifically, adjusting the frequency of at least one ultrasonic wave, when superimposed with the other, creates a non-steady-state standing wave with controlled directional movement of the wave packet and nodes. This controlled directional movement of the wave packet and nodes refers to adjusting the frequency of the ultrasonic waves to move the wave packet and nodes of the standing wave from the high-frequency converter to the low-frequency converter, thereby controlling the movement speed of the non-steady-state ultrasonic standing wave's wave packet and nodes by changing the frequency difference of the ultrasonic waves.

[0014] The aforementioned method for controlling the microstructure and properties of unsteady ultrasonic standing wave-assisted fusion welding refers to utilizing the mechanical and cavitation effects of power ultrasonic standing waves to make the resulting welded joint have a uniform microstructure, while refining the grains and reducing residual stress.

[0015] The above-mentioned method for nonsteady-state ultrasonic standing wave-assisted control fusion welding, wherein adjusting the parameters of dual-wave interference refers to adjusting the excitation frequency of at least one ultrasonic wave and the distance between the ultrasonic transducer, so as to obtain a nonsteady-state ultrasonic standing wave with energy-saving controlled directional movement of the wave packet.

[0016] In the above-mentioned method for unsteady ultrasonic standing wave assisted control of fusion welding, the amplitude of the ultrasonic wave is adjusted according to the microstructure and performance requirements of the molten zone and fusion zone in the welded joint.

[0017] The aforementioned method for nonsteady-state ultrasonic standing wave-assisted control of fusion welding, wherein the controlled directional movement of the wave packet node refers to obtaining a nonsteady-state ultrasonic standing wave by adjusting the excitation frequency of at least one ultrasonic wave to achieve unidirectional, reciprocating, or unidirectional-reciprocating spatiotemporal coupled movement of the wave packet node.

[0018] In the above-mentioned method for unsteady ultrasonic standing wave assisted control fusion welding, the number of dual ultrasonic transducers is one or more.

[0019] The apparatus used in the unsteady ultrasonic standing wave assisted control fusion welding method includes a fusion welding head, which is connected to a first ultrasonic transducer and a second ultrasonic transducer via a movable crossbeam. The first and second ultrasonic transducers are equipped with telescopic structures, and the first and second ultrasonic transducers are respectively connected to an ultrasonic elastic transmission head via springs and stress sensor patches.

[0020] The aforementioned unsteady-state ultrasonic standing wave-assisted control fusion welding device has a left and right adjustable distance knob on the moving crossbeam.

[0021] Beneficial effects:

[0022] This invention utilizes the interference principle of ultrasound to form an ultrasonic standing wave. By using the mutual interference of two ultrasonic waves with similar but different frequencies, a non-steady ultrasonic standing wave with controllable directional movement of wave packets and nodes is formed. Applying one or more sets of non-steady ultrasonic standing waves to the joint or different areas of the joint allows for regional control of the microstructure and properties of each area of ​​the welded joint, solving problems such as undercut, burn-through, large deformation, high stress, and embrittlement of the joint due to columnar crystals in the welding of thin materials and fine wires.

[0023] This unsteady standing wave can assist various welding methods, such as laser welding, electron beam welding, and arc welding. The mechanical effect of ultrasound can stir the molten pool, and the cavitation effect can form microjets. These effects have a significant impact on the microstructure control during the fusion welding process, resulting in a more uniform weld joint structure, refined grains, reduced residual stress, and improved mechanical properties and corrosion resistance. The mechanical and cavitation effects of ultrasound can also promote the wetting of molten metal on the base material surface, solving the problem of difficult wetting in some welding processes. It is widely used in the welding of dissimilar materials to improve the mechanical properties of the weld joint. Combined with appropriate fusion welding techniques (such as laser welding, electron beam welding, and arc welding), unsteady standing wave-assisted fusion welding technology is suitable for welding workpieces ranging from centimeter to micro / nano scales and for fusion welding of materials of various thicknesses. Compared with existing technologies, this invention enables directional transport of molten metal during the fusion welding process and allows for regional control of the amplitude applied to different parts of the weld joint (melting zone, fusion zone, heat-affected zone, and base metal zone), thereby achieving effective regulation of the weld joint's microstructure and properties. Specific effects are as follows:

[0024] This invention enables controllable connection of metal materials from the centimeter scale to the micrometer scale using dual-wave interference standing wave assisted fusion welding.

[0025] This invention utilizes the controlled directional movement of the wavelet nodes of an unsteady standing wave to achieve directional transport of molten pool metal, thus avoiding defects such as undercut and burn-through during the welding of thin materials and fine wires.

[0026] This invention can achieve quantitative control of directional transport of molten pool metal by adjusting the frequency difference of the two ultrasonic waves; at the same time, it can achieve the reciprocating movement of the unsteady standing wave packet node by adjusting the frequency of at least one ultrasonic wave, avoiding the occurrence of stirring blind zones in local areas, and making the joint composition and structure more uniform.

[0027] This invention can reduce residual stress and welding deformation in welded joints without breaking them due to ultrasonic vibration, while ensuring joint reliability.

[0028] This invention can prevent the formation of columnar structures at the weld joint while ensuring the reliability of the joint and preventing the weld joint from being broken by ultrasonic vibration, thereby improving the overall performance of the joint.

[0029] This invention allows for the application of different amplitudes to different parts of the joint (molten zone, fusion zone, heat-affected zone, and base metal zone) during the fusion welding process by adjusting the position, frequency, and amplitude of the dual ultrasonic waves. For example, in the fusion zone, where the metal viscosity is high and fluidity is low, a larger amplitude can be applied to obtain sufficient energy to promote the dispersion and movement of grain nucleation centers, hindering the epitaxial growth of grains from the fusion line towards the weld center to form columnar crystals. Conversely, in the molten zone, where the temperature is relatively high and the liquid metal viscosity is low, a smaller amplitude can be applied to ensure that the joint does not break. By applying different amplitudes to different parts of the joint, the microstructure and properties of each region of the joint can be controlled in a zonal manner. Attached Figure Description

[0030] Figure 1 This is a simplified diagram of the device for implementing the non-steady-state ultrasonic standing wave assisted control fusion welding technology described in this invention;

[0031] Figure 2 This is a schematic diagram of a common ultrasonic transmission principle;

[0032] Figure 3 This is a diagram illustrating the principle of standing wave formation through double interference.

[0033] Figure 4 This diagram illustrates a fusion welding technique where the molten zone and heat-affected zone do not vibrate, while the fusion zone and base material zone vibrate with standing waves to assist in fusion welding.

[0034] Figure 5 Diagram of standing wave-assisted fusion welding technology where the molten zone and heat-affected zone vibrate while the fusion zone and base material zone do not vibrate.

[0035] Figure 6 This is a schematic diagram of the standing wave-assisted control fusion welding technology.

[0036] The attached diagram is labeled as follows: 1-Left ultrasonic wave; 2-Right ultrasonic wave; 3-Standing wave; 4-Thin plate to be welded; 5-Spring; 6-First ultrasonic transducer; 7-Melting welding head; 8-Laser focusing plate; 9-Moving crossbeam; 10-Telescopic structure; 11-Second ultrasonic transducer; 12-Stress sensor patch; 13-Left and right distance adjustment knob; 14-Ultrasonic elastic transmission head.

[0037] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0038] Example 1. As... Figure 1 As shown, the device for unsteady-state ultrasonic standing wave assisted control fusion welding includes a fusion welding head 7. The fusion welding head 7 is connected to a first ultrasonic transducer 6 and a second ultrasonic transducer 11 via a movable crossbeam 9. The first ultrasonic transducer 6 and the second ultrasonic transducer 11 are equipped with telescopic structures 10. The first ultrasonic transducer 6 and the second ultrasonic transducer 11 are respectively connected to an ultrasonic elastic transmission head 14 via a spring 5 and a stress sensor patch 12. In this embodiment, the telescopic structure 10 uses an up-and-down adjusting nut, and the fusion welding head 7 is connected to a laser focusing plate 8 for laser welding. The positions of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 on the movable crossbeam 9 are adjustable.

[0039] The movable crossbeam 9 is equipped with a left and right adjustment knob 13 to adjust the left and right displacement of the fusion welding head 7.

[0040] Figure 1 In this process, the thin plates 4 to be welded consist of two plates with a thickness of several tens of micrometers. During use, the thin plates 4 are placed below the fusion welding head 7. By adjusting the telescopic structure 10 on the first ultrasonic transducer 6 and the second ultrasonic transducer 11, the ultrasonic elastic transmission head 14 contacts the thin plates 4 with a certain pressure. The first ultrasonic transducer 6 and the second ultrasonic transducer 11 simultaneously send ultrasonic waves of similar but not exactly equal frequencies, which are then introduced onto the thin plates 4 through the ultrasonic elastic transmission head 14. The first ultrasonic transducer 6 and the second ultrasonic transducer 11 generate left ultrasonic wave 1 and right ultrasonic wave 2, respectively. The left ultrasonic wave 1 and right ultrasonic wave 2 form a standing wave 3 in the welding section. The fusion welding head 7 simultaneously sends laser light, and the welding direction is transverse, that is, the fusion welding direction is perpendicular to the propagation direction of the ultrasonic waves.

[0041] A method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding includes the following steps:

[0042] S01. Using a dual ultrasonic transducer, dual-wave interference is performed to form an ultrasonic standing wave;

[0043] S02. Introducing ultrasonic standing waves into the fusion welding process, and using ultrasonic standing waves to act on the welding area to control the microstructure and properties of various parts of the welded joint in real time.

[0044] S03. By adjusting the parameters of the dual-wave interference, a non-steady-state ultrasonic standing wave with controllable directional movement of the wave packet nodes is formed, and the microstructure and properties of the welded joint are controlled by the non-steady-state standing wave.

[0045] The fusion welding includes laser welding, electron beam welding, and arc welding, etc.

[0046] The unsteady ultrasonic standing wave is formed by the superposition of two ultrasonic waves with unequal frequencies. Specifically, by adjusting the frequency of at least one ultrasonic wave, its superposition with the other ultrasonic wave forms an unsteady standing wave whose wave packet and nodes can move in a controlled direction. Controlled directional movement of the wave packet and nodes means that by adjusting the frequency of the ultrasonic waves, the wave packet and nodes of the standing wave can move from the high-frequency converter to the low-frequency converter; the movement speed of the unsteady standing wave's wave packet and nodes can be controlled by changing the frequency difference of the ultrasonic waves.

[0047] The regulation of the microstructure and properties refers to utilizing the mechanical and cavitation effects of ultrasonic standing waves to make the microstructure of the welded joint more uniform, while refining the grains and reducing residual stress, thereby improving the joint performance.

[0048] The adjustment of the parameters of the dual-wave interference refers to adjusting the excitation frequency of at least one ultrasonic wave and the distance between the ultrasonic transducer to obtain an unsteady ultrasonic standing wave with energy-saving controlled directional movement of the wave packet.

[0049] The controlled directional movement of the wave packet nodes refers to obtaining a non-steady ultrasonic standing wave by adjusting the excitation frequency of at least one ultrasonic wave to achieve unidirectional, reciprocating, or unidirectional-reciprocating spatiotemporal coupled movement of the wave packet nodes.

[0050] The amplitude of the ultrasonic standing wave is adjusted according to the microstructure and performance requirements of the molten zone and fusion zone in the welded joint.

[0051] The number of dual ultrasonic transducers is one or more.

[0052] During the welding process, the direction of metal transfer in the molten pool is controllable.

[0053] Step 1: Prepare the welding materials. The thickness of the materials to be welded is 30μm. Place the two pieces of welding materials on the welding platform.

[0054] Step 2: Set the laser welding process parameters: power 60W, welding speed 20mm / s, frequency 500Hz, duty cycle 20%.

[0055] Step 3: Adjust the positions of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 to the appropriate positions by sliding the crossbeam 9.

[0056] Step 4: Adjust the height of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 so that the ultrasonic elastic transmission head 14 contacts the sample, while ensuring that the spring 5 is subjected to a certain pressure. The pressure is sensed by the stress sensor patch 12, thereby ensuring that the ultrasonic waves are well transmitted to the sample.

[0057] Step 5: Set the amplitude and frequency of the ultrasound. In this implementation case, the amplitude is set to 30μm and the frequency is adjusted to 80kHz.

[0058] Step 6: Adjust the distance between the first ultrasonic transducer 6 and the second ultrasonic transducer 11 by using the left and right distance adjustment knobs. In this embodiment, the distance is adjusted to 104.25mm.

[0059] Step 7: Turn on any one of the ultrasound and laser to perform ultrasound-assisted laser controllable micro-nano connection.

[0060] Results Analysis: In this case, using only one ultrasonic wave achieved the effect of ordinary ultrasonic-assisted welding, such as... Figure 2 As shown, all particles in the metal melting zone, fusion zone, heat-affected zone, and base material zone experienced the same amplitude. Under the influence of ultrasonic waves and shear stress, the atoms exhibited a tendency to move as a whole, resulting in insignificant control over uniformity. Furthermore, due to the excessively thin welding material and excessively large amplitude, the two thin plates could not be effectively welded together, leading to welding failure.

[0061] Step 1: Prepare the welding materials. The thickness of the materials to be welded is 30μm. Place the two pieces of welding materials on the welding platform.

[0062] Step 2: Set the laser welding process parameters: power 60W, welding speed 20mm / s, frequency 500Hz, duty cycle 20%;

[0063] Step 3: Adjust the positions of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 to a suitable distance by sliding the crossbeam 9.

[0064] Step 4: Adjust the height of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 so that the ultrasonic elastic transmission head 14 contacts the sample, ensuring that the ultrasonic waves are well transmitted to the sample.

[0065] Step 5: Set the amplitude and frequency of the ultrasound. In this implementation case, the amplitude is set to 30μm, and the frequency of the ultrasound signals on the left and right sides is adjusted to 80 kHz.

[0066] Step 6: Adjust the distance between ultrasonic generator 1 and ultrasonic generator 2 by using the left and right distance adjustment knobs. In this embodiment, it is adjusted to 101.063 mm.

[0067] Step 7: Turn on the ultrasound and laser to perform dual-wave interference-assisted laser-controlled micro-nano connection.

[0068] Results Analysis: In this case, an ideal ultrasonic standing wave was obtained through the interference of two waves. Because the distance between the two interfering ultrasonic waves was 101.063 mm, the molten zone and heat-affected zone were always located near the antinodes of the standing wave. Under the high-speed vibration of the unsteady standing wave, the metal grains were sufficiently refined, particularly significantly inhibiting grain growth in the heat-affected zone. However, the fusion zone remained at the nodes of the standing wave, and its metal did not vibrate, resulting in columnar crystals and compositional inhomogeneity. The resulting joint fracture occurred in the fusion zone, and its mechanical properties showed no significant improvement. Example

[0069] Step 1: Prepare the welding materials. The thickness of the materials to be welded is 30μm. Place the two pieces of welding materials on the welding platform.

[0070] Step 2: Set the laser welding process parameters: power 60W, welding speed 20mm / s, frequency 500Hz, duty cycle 20%;

[0071] Step 3: Adjust the positions of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 to a suitable distance by sliding the crossbeam 9.

[0072] Step 4: Adjust the height of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 so that the ultrasonic elastic transmission head 14 contacts the sample, ensuring that the ultrasonic waves are well transmitted to the sample.

[0073] Step 5: Set the amplitude and frequency of the ultrasound. In this implementation case, the amplitude is set to 30μm, the frequency of the left ultrasound signal is adjusted to 80 kHz, and the frequency of the right ultrasound signal is linearly tuned between 75kHz and 85kHz.

[0074] Step 6: Adjust the distance between ultrasonic generator 1 and ultrasonic generator 2 by using the left and right distance adjustment knobs. In this embodiment, it is adjusted to 102.125 mm.

[0075] Step 7: Turn on the ultrasound and laser to perform dual-wave interference-assisted laser-controlled micro-nano connection.

[0076] Results Analysis: In this case, a non-steady-state ultrasonic standing wave with reciprocating wave packet nodes was obtained through the interference of two waves. Since the distance between the two interfering ultrasonic waves was 102.125 mm, the welding effect was as follows: Figure 4As shown, the molten metal zone and heat-affected zone are mainly located near the nodes, where the metal experiences slight vibration during the reciprocating movement of the wave packet nodes. The fusion zone is mainly located near the antinodes, where the metal atoms vibrate at high speed. Under the action of ultrasound, the wettability of the metal at the weld pool interface of the weld joint is improved. At the same time, due to the breaking effect of ultrasonic vibration, the columnar crystals in this region disappear, and equiaxed crystals are obtained, which increases the bonding strength of the material by about 25%. Example

[0077] Step 1: Prepare the welding materials. The thickness of the materials to be welded is 30μm. Place the two pieces of welding materials on the welding platform.

[0078] Step 2: Set the laser welding process parameters: power 60W, welding speed 20mm / s, frequency 500Hz, duty cycle 20%.

[0079] Step 3: Adjust the positions of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 to a suitable distance by sliding the crossbeam 9.

[0080] Step 4: Adjust the height of the first ultrasonic transducer 6 and the second ultrasonic transducer 11 so that the ultrasonic elastic transmission head 14 contacts the sample, ensuring that the ultrasonic waves are well transmitted to the sample.

[0081] Step 5: Set the amplitude and frequency of the ultrasound. In this implementation case, the amplitude is set to 30μm, the frequency of the left ultrasound signal is adjusted to 80 kHz, and the frequency of the right ultrasound signal is linearly tuned between 75kHz and 85kHz.

[0082] Step 6: Adjust the distance between ultrasonic generator 1 and ultrasonic generator 2 by using the left and right distance adjustment knobs. In this embodiment, it is adjusted to 101.063 mm.

[0083] Step 7: Turn on the ultrasound and laser to perform dual-wave interference-assisted laser-controlled micro-nano connection.

[0084] Results Analysis: In this case, a non-steady-state ultrasonic standing wave with reciprocating wave packet nodes was obtained through the interference of two waves. Since the distance between the two interfering ultrasonic waves is 101.063 mm, the welding effect is as follows: Figure 5 As shown, the molten zone and heat-affected zone are mainly located near the antinodes of the standing wave. Under the high-speed vibration of the unsteady standing wave, the grains in these zones are sufficiently refined, particularly significantly inhibiting grain growth in the heat-affected zone. The fusion zone is mainly located near the nodes of the standing wave, experiencing a small amount of vibration during the reciprocating movement of the wave packet and nodes, which plays a positive role in hindering columnar crystal formation and refining the grains. Under this experimental design, the plasticity of the welded joint is increased by approximately 33.8%.

[0085] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding, characterized in that: Includes the following steps: S01. Using dual ultrasonic transducers, dual-wave interference is performed to form an ultrasonic standing wave; S02. Introducing ultrasonic standing waves into the fusion welding process, by applying ultrasonic standing waves to the welding area, the microstructure and properties of various parts of the welded joint can be controlled in real time. S03. By adjusting the parameters of the dual-wave interference, an unsteady ultrasonic standing wave with energy-saving and controlled directional movement of the wave packet is formed, and the microstructure and properties of the welded joint are controlled by the unsteady standing wave. The unsteady ultrasonic standing wave is formed by superimposing two ultrasonic waves with not exactly equal frequencies. When the frequency of at least one ultrasonic wave is adjusted and superimposed with the other ultrasonic wave, a unsteady standing wave with controlled directional movement of wave packet and nodes is formed. The controlled directional movement of wave packet and nodes refers to adjusting the frequency of the ultrasonic waves to move the wave packet and nodes of the standing wave from the high-frequency converter to the low-frequency converter. The movement speed of the unsteady ultrasonic standing wave wave packet and nodes is controlled by changing the frequency difference of the ultrasonic waves.

2. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 1, characterized in that: The fusion welding includes laser welding, electron beam welding, or arc welding.

3. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 1, characterized in that: The regulation of the structure and properties refers to using the mechanical and cavitation effects of power ultrasonic standing waves to make the structure of the welded joint uniform, while refining the grains and reducing residual stress.

4. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 1, characterized in that: The adjustment of the parameters of the dual-wave interference refers to adjusting the excitation frequency of at least one ultrasonic wave and the distance between the ultrasonic transducer to obtain an unsteady ultrasonic standing wave with energy-saving controlled directional movement of the wave packet.

5. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 4, characterized in that: The amplitude of the ultrasonic wave is adjusted according to the microstructure and performance requirements of the molten zone and fusion zone in the welded joint.

6. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 1, characterized in that: The controlled directional movement of the wave packet nodes refers to obtaining a non-steady ultrasonic standing wave by adjusting the excitation frequency of at least one ultrasonic wave to achieve unidirectional, reciprocating, or unidirectional-reciprocating spatiotemporal coupled movement of the wave packet nodes.

7. The method for unsteady-state ultrasonic standing wave-assisted controlled fusion welding according to claim 1, characterized in that: The number of dual ultrasonic transducers is one or more.

8. An apparatus for unsteady-state ultrasonic standing wave-assisted controlled fusion welding, employing the method described in any one of claims 1-7, characterized in that: It includes a fusion welding head (7), which is connected to a first ultrasonic transducer (6) and a second ultrasonic transducer (11) via a movable crossbeam (9). The first ultrasonic transducer (6) and the second ultrasonic transducer (11) are provided with a telescopic structure (10). The first ultrasonic transducer (6) and the second ultrasonic transducer (11) are connected to an ultrasonic elastic transmission head (14) via a spring (5) and a stress sensor patch (12), respectively.

9. The apparatus for unsteady-state ultrasonic standing wave assisted control fusion welding according to claim 8, characterized in that: The movable crossbeam (9) is equipped with a left and right adjustment knob (13).

Images