Electromagnetic pulse processing apparatus and method for zone-specific tailored strengthening of metal weld joints

Abstract

This invention discloses an electromagnetic pulse treatment device and method for zoned customized reinforcement of metal welded joints, belonging to the technical field of post-weld modification treatment of metal welded joints. It includes an upper mold, a lower mold, welded sheet metal, an insulating baffle, a magnet collector, a fixing device, a discharge coil, and a pulse discharge circuit. The heat-affected zones on both sides of the welded sheet metal are first subjected to transient pulse current treatment near the weld seam by induced eddy currents. The weld seam is then subjected to a high-energy pulsed strong magnetic field collected by the magnet collector. Furthermore, due to the contraction effect of the induced eddy currents and the diffusion effect of the pulsed strong magnetic field, both the weld seam and the heat-affected zone are further affected by the current and magnetic field during the attenuation of the electromagnetic energy field. This invention induces intense Joule heating, shock waves, and electromagnetic energy effects at the interface of heterogeneous joints through high-energy electromagnetic pulses, thereby instantly achieving the precipitation of nano-reinforcing phases and eliminating defects. It possesses advantages such as high flexibility, high efficiency, high performance, and high reliability.

Description

Technical Field

[0001] This invention relates to the field of post-weld modification treatment technology for metal welded joints, and in particular to an electromagnetic pulse treatment device and method for zoned customized strengthening of metal welded joints. Background Technology

[0002] Electromagnetic pulse (EMP) treatment is an advanced technology that uses high-energy pulsed electromagnetic fields to modify and strengthen metallic materials. This technology induces eddy currents within the workpiece by instantaneously applying extremely high pulsed currents, generating intense Joule heating, shock wave effects, and electromagnetic force effects. This leads to grain refinement, defect repair, and the precipitation of strengthening phases, ultimately improving the material's mechanical properties. Compared to traditional heat treatment or mechanical treatment, EMP treatment offers advantages such as precise energy control, high processing efficiency, and minimal workpiece deformation, demonstrating significant potential for improving the performance of dissimilar metal welded joints.

[0003] Dissimilar metal welded joints are widely used in aerospace, automotive manufacturing, and nuclear power equipment due to their ability to complement material properties. However, during the welding process, the differences in the physicochemical properties of the base materials often lead to problems such as uneven microstructure, residual stress concentration, and numerous micro-defects (such as porosity and microcracks) in the weld fusion zone and heat-affected zone. These issues become weak points in the service life of the components, seriously affecting the reliability and lifespan of the overall structure.

[0004] Existing post-weld modification methods, such as ultrasonic shock blasting, laser shock blasting, and traditional heat treatment, can improve joint performance to some extent, but all have limitations. Ultrasonic shock blasting has high requirements on the shape of the component and the reinforced layer is shallow; laser shock blasting equipment is expensive and easily causes thermal damage to the material surface; traditional heat treatment involves overall heating, making it difficult to achieve "precise treatment" for different areas of the joint, and may cause degradation of the base material properties. Electromagnetic pulse treatment, as a bulk treatment technology, can overcome some of the above shortcomings, but existing electromagnetic pulse treatment devices usually use a uniform magnetic field, which cannot apply differentiated energy to different areas such as the weld and heat-affected zone, resulting in limited strengthening effect, and may even cause over-treatment or under-treatment of some areas due to energy mismatch.

[0005] Therefore, without changing the inherent advantages of electromagnetic pulse processing such as high efficiency and non-contact operation, how to achieve precise control and customized distribution of energy fields in different micro-regions of welded joints, and fundamentally solve the problems of uneven strengthening and incomplete modification of heterogeneous joints, has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an electromagnetic pulse treatment device and method for zoned customized strengthening of metal welded joints. By introducing a magnetizer with magnetic field focusing function, and precisely positioning its specific interface to correspond to different microscopic regions of the welded joint (weld zone, fusion zone, and heat-affected zone), a high-energy pulsed strong magnetic field is applied to the weld and fusion zone of the dissimilar joint during a single pulse discharge, while induced eddy current treatment is applied to both heat-affected zones. This invention, through the zoned design and coupling effect of the energy field, achieves synergistic strengthening and modification of the overall performance of the welded joint in a single process.

[0007] To achieve the above objectives, this invention provides an electromagnetic pulse treatment device for customized reinforcement of metal welded joints, comprising an upper mold, a lower mold, weldable sheet metal, an insulating baffle, a magnet collector, a fixing device, a discharge coil, and a pulse discharge circuit. The upper mold, lower mold, and fixing device are combined to secure and position the weldable sheet metal, magnet collector, and discharge coil—the core components of the electromagnetic pulse treatment mechanism. The pulse discharge circuit is connected to the discharge coil to form a pulsed electromagnetic field.

[0008] The magnet collector has a conical structure and a conical through hole inside to achieve magnetic field flow line convergence; the outer contour of the lower surface of the magnet collector is consistent with the contour of the discharge coil and is placed in a covering manner; the through hole interface on the upper surface of the magnet collector is directly opposite the fusion zone of the center weld of the welded plate, and the interfaces on both sides of the upper surface are directly opposite the heat-affected zones of the metal plates on both sides.

[0009] Preferably, the width of the interfaces on both sides of the upper surface of the magnet collector can be freely designed and changed according to the range of the heat-affected zone and the electrical conductivity of the base materials on both sides of the welded plate, so as to achieve the best match between energy delivery and regional characteristics.

[0010] Preferably, the discharge coil is a planar helical coil or an irregularly shaped coil adapted to the contour of the welded sheet material to provide a uniform initial pulse magnetic field.

[0011] Preferably, the upper mold, lower mold, and fixing device are made of high-strength insulating material or metal material with poor conductivity to avoid the formation of eddy currents and ensure that energy is efficiently transferred to the joint area to be processed.

[0012] This invention also provides a method for customized reinforcement of metal welded joints using electromagnetic pulse treatment, applied to the aforementioned device for customized reinforcement of metal welded joints using electromagnetic pulse treatment, comprising the following steps:

[0013] S1. Place the welded sheet material between the upper and lower molds and fix it in place;

[0014] S2. Start the pulse discharge circuit to generate a pulsed electromagnetic field in the discharge coil;

[0015] S3. The pulsed magnetic field is concentrated by the magnet collector, so that it acts on the fusion zone of the central weld seam of the welded plates with high intensity;

[0016] S4. At the same time, the heat-affected zone on both sides of the welded sheet is subjected to transient pulse current processing by utilizing the effect of induced eddy current.

[0017] Preferably, step S1 includes the following specific steps:

[0018] Place the welded sheet material on the magnet collector, isolate it with an insulating baffle and ensure that the weld area is accurately positioned;

[0019] Adjust the position of the magnet to ensure that the through-hole interface on its upper surface is precisely aligned with the weld and fusion zone, and the interfaces on both sides are aligned with the heat-affected zones on both sides.

[0020] Place the discharge coil under the magnet collector, ensuring that the magnet collector covers the outer contour of the discharge coil, and reliably connect it to the pulse discharge circuit.

[0021] Close the upper mold and secure the entire assembly with a fixing device to ensure that each component remains stable during the discharge process.

[0022] Preferably, in step S4, the pulse current treatment acting on the central weld fusion zone is mainly due to the diffusion effect of the pulsed strong magnetic field, while the pulse current treatment acting on the heat-affected zones on both sides is mainly due to the contraction effect of induced eddy currents. The weld and heat-affected zones are simultaneously subjected to the effects of current and magnetic field during the electromagnetic field attenuation process.

[0023] Preferably, in step S4, the pulsed current treatment can induce Joule heating, shock wave and electromagnetic force effects at the heterojunction interface, thereby achieving nano-reinforced phase precipitation and defect elimination, and achieving the effect of zoned customized reinforcement.

[0024] Therefore, the electromagnetic pulse processing device and method for partitioned customized reinforcement of metal welded joints using the above-described structure of the present invention has the following beneficial effects:

[0025] (1) Through the design of the magnet collector, the present invention achieves differentiated and precise energy application to the weld (mainly by strong magnetic field diffusion) and the heat-affected zone (mainly by induced eddy current contraction) in electromagnetic pulse processing, solving the problem that traditional single energy field is difficult to optimize all areas of the joint at the same time, and realizing customized strengthening of "one zone, one policy".

[0026] (2) In this invention, a single pulse discharge can simultaneously process multiple areas such as weld seams and heat-affected zones, resulting in high processing efficiency. The precise delivery of the energy field avoids energy waste and damage to the base material properties, and can more effectively induce the precipitation of nano-reinforcing phases, eliminate microscopic defects, reduce residual stress, and significantly improve the comprehensive mechanical properties of the joint.

[0027] (3) By changing or redesigning the interface size of the upper surface of the magnet collector, the device and method can be flexibly applied to welding structures with different materials, different plate thicknesses and different joint forms. The process is highly flexible and is conducive to promotion and application in industrial production.

[0028] (4) The device provided by the present invention has a compact structure, simple tooling, can be well integrated with existing welding production lines, is easy to operate, and is conducive to the batch and standardized operation of this strengthening process, which has significant economic benefits.

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the present invention;

[0031] Figure 2 This is a schematic diagram of the core components of the present invention;

[0032] Figure 3 This is a cross-sectional view of the core component of the present invention;

[0033] Figure 4 This is a schematic diagram of the discharge circuit system of the present invention;

[0034] Figure Labels

[0035] 1-Upper mold; 2-Welded sheet metal; 3-Insulating baffle; 4-Magnetic collector; 5-Fixing device; 6-Discharge coil; 7-Lower mold; 8-Winding coil; 9-Inductor; 10-Resistor; 11-Capacitor bank; 12-Switch. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] Example

[0039] like Figures 1-4 As shown, this invention provides an electromagnetic pulse treatment device for customized reinforcement of metal welded joints, comprising an upper mold 1, a weldable sheet 2, an insulating baffle 3, a magnet collector 4, a fixing device 5, a discharge coil 6, a lower mold 7, a winding coil 8, an inductive element 9, a resistive element 10, a capacitor bank 11, and a switch 12. The upper mold 1, lower mold 7, and fixing device 5 together form a fixture for fastening and positioning the weldable sheet 2, the magnet collector 4, and the discharge coil 6. The pulse discharge circuit is connected to the winding coil 8 in the discharge coil 6 to generate a high-energy pulsed electromagnetic field.

[0040] Furthermore, the welded sheet 2, the magnet collector 4, and the winding coil 8 are the core components of this device; see the schematic diagram for their specific structure. Figure 2 and Figure 3 The magnet collector 4 has an overall conical structure with conical through-holes machined inside. Its function is to collect the magnetic field lines generated by the lower winding coil 8 and guide them to a specific area above. The lower surface profile of the magnet collector 4 perfectly matches the upper surface profile of the winding coil 8 and is placed in a covering manner to ensure efficient magnetic field coupling. The upper surface of the magnet collector 4 is designed with key functional interfaces: a central through-hole interface and two side interfaces. The central through-hole interface is precisely aligned with the weld seam and fusion zone of the welded sheet 2 during assembly, while the side interfaces are respectively aligned with the heat-affected zones on both sides of the welded sheet.

[0041] Specifically, a typical pulse discharge circuit consists of a capacitor bank, an inductive element, a resistive element, and an RLC oscillating circuit formed by connecting a circuit switch in series.

[0042] Specifically, the winding coil 8 is preferably a multi-turn, closely wound planar racetrack-shaped coil made of highly conductive copper. Its specific number of turns and wire diameter can be designed according to the size of the workpiece being processed and the required energy. For example, the outer diameter of the coil can be in the range of 10~200mm, and the cross-sectional area of ​​the conductor can be in the range of 4~30mm². 2 Within the range.

[0043] Specifically, the upper mold 1 and the lower mold 7 are preferably made of hard alloy steel with poor conductivity or high-strength insulating materials such as epoxy glass cloth to avoid unnecessary eddy current diversion and ensure that energy is concentrated on the joint area to be treated.

[0044] This invention also provides a method for customized reinforcement of metal welded joints using electromagnetic pulse treatment, applied to the aforementioned device for customized reinforcement of metal welded joints using electromagnetic pulse treatment, comprising the following steps:

[0045] S1. First, install and fix the discharge coil 6 at the designated position of the lower mold 7, and reliably connect its terminals to the pulse discharge circuit.

[0046] S2. Place the magnet collector 4 above the discharge coil 6, ensuring that its lower surface is completely in contact with the coil outline, and adjust the position of the magnet collector so that the position of the central through hole interface and the two side interfaces on its upper surface corresponds to the preset welding plate processing area.

[0047] S3. Place the insulating baffle 3 on top of the magnet collector 4 to provide insulation.

[0048] S4. Place the welded sheet 2 above the insulating baffle 3 and ensure that the center line of its weld is precisely aligned with the center through hole interface of the magnet collector 4 by using positioning pins or reference edges.

[0049] S5. Close the upper mold 1 and apply appropriate fastening force through the fixing device 5 to press and fix the entire assembly from the lower mold to the welded plate material, ensuring that each component does not shift under the discharge impact.

[0050] S6. After verifying that the circuit connection is correct, close the switch of the pulse discharge circuit. The electrical energy stored in the capacitor bank is released through the winding coil 8 in a very short time, generating a transient strong pulse magnetic field. This magnetic field is collected by the magnet collector 4 to form a high-energy-density magnetic field acting on the weld area; at the same time, the heat-affected zones on both sides of the welded sheet 2 induce strong eddy currents in the changing magnetic field, generating a Joule heating effect; under the combined action of the electromagnetic field, the joint area achieves nanoscale grain refinement, micro-defect repair, and precipitation of strengthening phases, thereby completing the strengthening modification.

[0051] In this invention, after the welded sheet material 2 undergoes strengthening treatment, its weld seam and heat-affected zone exhibit uneven microstructure and micro-defects. When pulsed discharge occurs, a high-energy electromagnetic field acts on the joint in sections, resulting in a microstructure characterized by grain refinement and reduced defects, thereby improving performance.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for zoned customized reinforcement of electromagnetic pulse treatment in metal welded joints, characterized in that, Includes the following steps: S1. Place the welded sheet material between the upper and lower molds and fix it in place; Step S1 further includes: adjusting the position of the magnet collector to ensure that the through-hole interface on its upper surface is precisely aligned with the weld and fusion zone, and the interfaces on both sides are aligned with the heat-affected zones on both sides. S2. Start the pulse discharge circuit to generate a pulsed electromagnetic field in the discharge coil; S3. The pulsed magnetic field is gathered by a magnet collector and applied to the fusion zone of the central weld seam of the welded plates. S4. At the same time, the heat-affected zone on both sides of the welded sheet is subjected to transient pulse current treatment using the effect of induced eddy current. In step S4, the pulse current treatment applied to the fusion zone of the central weld is mainly due to the diffusion effect of the pulsed strong magnetic field, while the pulse current treatment applied to the heat-affected zones on both sides is mainly due to the contraction effect of induced eddy currents. The weld and heat-affected zones are simultaneously subjected to the effects of current and magnetic field during the electromagnetic field attenuation process. In step S4, the pulsed current treatment can induce Joule heating, shock wave and electromagnetic force effects at the heterojunction interface, thereby realizing the precipitation of nano-reinforced phase and defect elimination, achieving the effect of zoned customized reinforcement. Its device includes: Upper mold, lower mold, magnet collector, discharge coil, and pulse discharge circuit; The upper and lower molds are combined to position and fix the welded sheet material to be processed; The pulse discharge circuit is connected to the discharge coil and is used to generate pulse current; The magnet collector is positioned between the discharge coil and the welded sheet material, and has a tapered through hole inside to collect and guide the pulsed magnetic field to act on a specific area of ​​the welded sheet material. The lower surface contour of the magnet collector is consistent with the contour of the discharge coil and is placed in a covering manner, and the tapered through-hole interface on its upper surface is directly opposite the center weld and fusion zone of the welded sheet material. The two sides of the tapered through hole on the upper surface of the magnet collector are directly opposite the heat-affected zones on both sides of the welded sheet.

2. The electromagnetic pulse treatment method for zoned customized reinforcement of metal welded joints according to claim 1, characterized in that, The specific steps of step S1 include: Place the welded sheet material on the magnet collector, isolate it with an insulating baffle and ensure that the weld area is accurately positioned; Place the discharge coil under the magnet collector, ensuring that the magnet collector covers the outer contour of the discharge coil, and reliably connect it to the pulse discharge circuit. Close the upper mold and secure the entire assembly with a fixing device to ensure that each component remains stable during the discharge process.

3. The electromagnetic pulse treatment method for zoned customized reinforcement of metal welded joints according to claim 1, characterized in that, The width of the interfaces on both sides of the upper surface of the magnet collector is customized according to the range of the heat-affected zone and the conductivity of the metal on both sides of the welded sheet.

4. The electromagnetic pulse treatment method for zoned customized reinforcement of metal welded joints according to claim 1, characterized in that, The discharge coil is a planar spiral coil or an irregularly shaped coil adapted to the contour of the welded sheet material.

5. The electromagnetic pulse treatment method for zoned customized reinforcement of metal welded joints according to claim 1, characterized in that, The upper and lower molds are made of high-strength insulating materials or metal materials with poor conductivity.

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