Magnetic pulse strengthening device and process for improving performance of additive forming workpiece

Abstract

The invention discloses a magnetic pulse strengthening device and process for improving the performance of an additive forming workpiece, the magnetic pulse strengthening device comprises a base, an additive forming table and a first vertical positioning mechanism, and the first vertical positioning mechanism is connected with a lifting positioning plate; a horizontal longitudinal positioning mechanism and a second vertical positioning mechanism are fixedly arranged on the top face of the lifting positioning plate, a horizontal transverse positioning mechanism is arranged on the horizontal longitudinal positioning mechanism, an arc fuse wire additive welding gun assembly is arranged on the horizontal transverse positioning mechanism, and a magnetic pulse strengthening assembly is connected to the second vertical positioning mechanism. Every time the arc fuse wire additive welding gun assembly completes additive deposition forming of one layer, the magnetic pulse strengthening assembly conducts impact strengthening on the top surface of the workpiece through magnetic field force. According to the method, the electromagnetic forming technology is creatively applied to post-treatment of the WAAM technology, magnetic pulse strengthening plastic deformation on the surface of the workpiece is achieved, the influence layer depth is high, and the mechanical property and uniformity of the material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal plastic processing and forming, and in particular to a magnetic pulse strengthening device and process for improving the performance of additively formed workpieces. Background Art

[0002] Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing method that uses an arc welding gun to melt the metal and then weld it layer by layer to finally form the target workpiece blank, and then achieve the dimensional accuracy and surface quality of the design target through subsequent machining. It is characterized by high deposition efficiency, low equipment cost, high material utilization rate and environmental friendliness. Although the mechanical properties of parts produced by WAAM are comparable to those of similar products produced by traditional processing in many cases, there are still some processing defects that must be solved in critical applications. In the application process of WAAM production workpieces, pores, high residual tensile stresses and cracks must be avoided, which will lead to a significant decrease in the performance of the formed workpiece. The existence of these defects has greatly restricted the further development and application of WAAM.

[0003] In addition to adjusting process parameters and subsequent heat treatment processes to improve the microstructure of formed parts and enhance the comprehensive mechanical properties, some scholars have also introduced traditional plastic forming processes into arc additive manufacturing, forming arc additive plastic forming composite manufacturing technologies such as ultrasonic laser impact composite technology, high-frequency micro-forging composite technology, and rolling composite technology. These composite technologies have certain effects in regulating residual stress, refining grains, and improving performance, but there are also problems such as damage to surface quality, low depth of the affected layer, and high heat input. Therefore, it is urgent to develop new technologies with good surface integrity, high depth of the affected layer, and less heat input to improve the residual stress of workpieces after additive manufacturing. Summary of the invention

[0004] In view of the above-mentioned defects and deficiencies, the present invention provides a magnetic pulse strengthening device and process for improving the performance of additively formed workpieces. The device is based on an RLC discharge circuit, which is charged during the additive process and then discharged. The current generates a strong magnetic field through the working coil, and the special-shaped magnetic collector can control the distribution of the magnetic field, generate induced current and magnetic field in the metal workpiece, so that the workpiece is subjected to multi-directional magnetic field forces. Under the action of the magnetic field force, the workpiece is plastically deformed, and the residual tensile stress generated during the additive process is improved. At the same time, the shape of the workpiece can be prevented from being greatly changed, and the subsequent machining allowance can be reduced. The magnetic pulse strengthening process is non-contact, has little effect on the workpiece surface, and can improve the surface integrity; the strain rate is large, and the depth of the affected layer is deep; the action time is short, and it is not easy to cause remelting of the workpiece. It can effectively improve the structure after additives and eliminate internal defects, and has significant advantages.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: A magnetic pulse strengthening device for improving the performance of an additively formed workpiece, comprising a base, an additive forming table fixedly arranged on the top surface of the base, and a first vertical positioning mechanism, wherein the positioning output end of the first vertical positioning mechanism is fixedly connected to a lifting positioning plate sleeved on the outside of the additive forming table, the top surface of the lifting positioning plate is respectively fixedly provided with a horizontal longitudinal positioning mechanism and a second vertical positioning mechanism, the positioning output end of the horizontal longitudinal positioning mechanism is fixedly connected to a horizontal transverse positioning mechanism, the positioning output end of the horizontal transverse positioning mechanism is fixedly connected to an arc fuse additive welding gun assembly located above the top surface of the additive forming table, the positioning output end of the second vertical positioning mechanism is fixedly connected to a lifting frame plate, and the bottom of the lifting frame plate is provided with a magnetic pulse strengthening assembly located just above the top surface of the additive forming table; The horizontal longitudinal positioning mechanism and the horizontal lateral positioning mechanism drive the arc fuse additive welding gun assembly to additively deposit and form the workpiece layer by layer on the additive forming table. After each layer of additive deposition is completed, the second vertical positioning mechanism drives the magnetic pulse strengthening assembly to position to the outer side of the top of the additively formed workpiece. The magnetic pulse strengthening assembly impact-strengthens the top surface of the workpiece through the magnetic field force.

[0006] Furthermore, the magnetic pulse enhancement component includes a magnetic collector with an inverted cone-shaped hollow structure, and a magnetic pulse enhancement coil coaxially arranged on the top surface of the magnetic collector. A strengthening groove matching the top contour of the cross-sectional shape of the workpiece is provided on the bottom surface of the magnetic collector. The magnetic pulse enhancement coil is a spiral wire structure, and its two ends are respectively connected to the two output electrodes of the magnetic pulse enhancement device.

[0007] Furthermore, the system circuit of the magnetic pulse enhancement device includes a power supply, a capacitor, a capacitor switch, an inductor and a resistor. One end electrode of the power supply is connected to one end of the magnetic pulse enhancement coil, the other end electrode of the power supply is connected in series with the inductor and the resistor in sequence and then connected to the other end of the magnetic pulse enhancement coil. The capacitor is connected in series with the capacitor switch and then connected in parallel with the two electrode ends of the power supply.

[0008] Furthermore, the maximum discharge energy of the magnetic pulse enhancement device is 100~150kJ, the capacitance of the capacitor (1032) is 160~320 μF, and the discharge voltage is 5~20kV.

[0009] Furthermore, the bottom of the lifting frame plate is fixedly connected to a mounting frame plate, the bottom of the mounting frame plate is fixedly connected to a clamping cylinder, the bottom of the clamping cylinder is detachably connected to a clamping pressure plate, the top surface edge of the magnetic collector is clamped between the clamping pressure plate and the clamping cylinder, and the magnetic pulse enhancement coil is located in the clamping cylinder.

[0010] A magnetic pulse strengthening process for improving the performance of an additively formed workpiece is also provided, which is applied to the magnetic pulse strengthening device for improving the performance of an additively formed workpiece as described above, and comprises the following steps: S1, system initialization, device reset: the second vertical positioning mechanism drives the magnetic pulse strengthening assembly to rise and reset to the top of the area to be added on the additive forming table, and the horizontal longitudinal positioning mechanism and the horizontal lateral positioning mechanism drive the arc fuse additive welding gun assembly to move horizontally and reset to the top side of the area to be added on the additive forming table; S2. Arc fuse single-layer additive: the horizontal longitudinal positioning mechanism and the horizontal transverse positioning mechanism drive the arc fuse additive welding gun assembly to move to the area to be added on the additive forming table, and drive the arc fuse additive welding gun assembly to move according to a preset forming route. The arc fuse additive welding gun assembly extrude the molten metal during the movement, and the molten metal is deposited and formed. The horizontal longitudinal positioning mechanism and the horizontal transverse positioning mechanism drive the arc fuse additive welding gun assembly to move and reset. S3, magnetic pulse surface strengthening: the second vertical positioning mechanism drives the magnetic pulse strengthening component to move downward to the top outer side of the additively formed workpiece, and the magnetic pulse strengthening component performs impact strengthening on the top surface of the workpiece through the magnetic field force. After the preset impact strengthening time, the second vertical positioning mechanism drives the magnetic pulse strengthening component to rise and reset; S4, additive height feeding: the first vertical positioning mechanism drives the arc fuse additive welding gun assembly to move up a single-layer additive height; S5, cyclic additive and strengthening process: repeating the above steps S2 to S4, completing the additive deposition forming process of the workpiece layer by layer on the additive forming table, and completing the impact strengthening of the top surface of the workpiece after each layer of additive deposition forming; S6. Remove the sample: the device stops working, and the additively formed workpiece is removed from the additive forming table after cooling to room temperature.

[0011] Furthermore, in step S3, the distance between the side surface of the strengthening groove on the bottom surface of the magnetic collector and the top outer surface of the additively formed workpiece is 0.5-2 mm, and the preset impact strengthening time is 0.001-1 ms.

[0012] Furthermore, after step S6, the relationship between the magnetic pulse strengthening parameters and the grain size, metallurgical defects and residual stress is determined through metallographic observation and residual stress detection.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention sets a magnetic pulse strengthening component, and generates a magnetic field force through the electromagnetic field released by the magnetic pulse strengthening coil to impact strengthen the top surface of the additive workpiece. The strain rate in electromagnetic forming is very high (strain rate 10 3 -10 4 s-1 ), the high strain rate hardening effect of high-speed deformation can be used to improve the effect of magnetic pulse strengthening, thereby introducing a residual stress field and a certain degree of surface hardening to the workpiece surface, thereby improving the fatigue strength of the workpiece; 2. The magnetic pulse surface impact strengthening process adopted by the present invention belongs to non-contact impact strengthening. During the strengthening process, the surface integrity and surface quality of the workpiece are good, which reduces the amount of subsequent machining. At the same time, the magnetic pulse strengthening process has a short action time of only 0.001-1ms, which can complete the surface strengthening of the additive workpiece in a very short time, with high strengthening efficiency and not easy to cause remelting of the workpiece. It can achieve the regulation of the workpiece structure and performance without destroying the basic shape of the additive workpiece. 3. The present invention uses a special-shaped magnetic collector to adjust the magnetic field distribution during the magnetic pulse strengthening process, so that the top surface of the workpiece is subjected to three-dimensional compressive stress during the magnetic pulse surface impact strengthening process, which significantly improves the distribution of residual stress inside the workpiece and effectively refines the grains. It can effectively repair the internal pores, cracks and other defects of the workpiece after material addition, adjust its residual stress, and improve the comprehensive performance of the workpiece; 4. The present invention uses an RLC circuit to charge the capacitor during the material addition process, which saves charging time and improves work efficiency; 5. The present invention can design the anisotropic magnetic collector into various shapes to meet the application needs of the magnetic pulse surface impact strengthening process of additive workpieces with different shapes, and has good adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is one of the three-dimensional structural schematic diagrams of the magnetic pulse enhancement device of the present invention; Figure 2 This is the second schematic diagram of the three-dimensional structure of the magnetic pulse enhancement device of the present invention; Figure 3 It is a schematic diagram of the three-dimensional structure of the magnetic pulse enhancement component in Example 1; Figure 4 This is a schematic diagram of the working state of the magnetic pulse enhancement component in Example 1; Figure 5 for Figure 4 The enlarged structural diagram of the middle A part; Figure 6 for Figure 4 A schematic diagram of the enlarged structure of the middle B part; Figure 7 It is a structural schematic diagram of the system circuit of the magnetic pulse enhanced power module of the present invention; Figure 8 The working process of the magnetic pulse strengthening process of the present invention; Fig. 9The overall effect of the performance test of the cylindrical additive workpiece in Example 1 using the magnetic pulse strengthening process; Fig.10 This is a cross-sectional view of the performance test of the additive workpiece in Example 1 using the magnetic pulse strengthening process; Fig.11 It is a schematic diagram of the three-dimensional structure of the magnetic pulse enhancement component in Example 2; Fig.12 This is a schematic diagram of the working state of the magnetic pulse strengthening component in Example 2; Fig.13 The overall effect of the performance test of the cylindrical additive workpiece in Example 2 using the magnetic pulse strengthening process; Fig.14 This is a cross-sectional view of the performance test of the additive workpiece in Example 2 using the magnetic pulse strengthening process.

[0015] In the figure: 1. Magnetic pulse enhancement component; 101. Magnetic collector; 102. Magnetic pulse enhancement coil; 103. Magnetic pulse enhancement power supply module; 1031. Power supply; 1032. Capacitor; 1033. Capacitor switch; 1034. Inductor; 1035. Resistor; 2. Additive forming table; 3. First vertical positioning mechanism; 4. Lifting positioning plate; 5. Horizontal longitudinal positioning mechanism; 6. Second vertical positioning mechanism; 7. Horizontal transverse positioning mechanism; 8. Arc fuse additive welding gun assembly; 9. Lifting frame plate; 901. Mounting frame plate; 902. Clamping cylinder; 903. Clamping pressure plate; 10. Base. DETAILED DESCRIPTION

[0016] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0017] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0019] Embodiment 1: See also Figure 1 and Figure 2 The present invention provides a magnetic pulse strengthening device for improving the performance of additively formed workpieces, comprising a base 10, an additive forming table 2 fixedly arranged on the top surface of the base 10, and a first vertical positioning mechanism 3, the positioning output end of the first vertical positioning mechanism 3 is fixedly connected to a lifting positioning plate 4 sleeved on the outside of the additive forming table 2, the top surface of the lifting positioning plate 4 is respectively fixedly provided with a horizontal longitudinal positioning mechanism 5 and a second vertical positioning mechanism 6, the positioning output end of the horizontal longitudinal positioning mechanism 5 is fixedly connected to a horizontal transverse positioning mechanism 7, the positioning output end of the horizontal transverse positioning mechanism 7 is fixedly connected to an arc fuse additive welding gun assembly 8 located above the top surface of the additive forming table 2, the positioning output end of the second vertical positioning mechanism 6 is fixedly connected to a lifting frame plate 9, and the bottom of the lifting frame plate 9 is provided with a magnetic pulse strengthening assembly 1 located just above the top surface of the additive forming table 2.

[0020] The present device involves an arc fuse additive manufacturing process, so the arc fuse additive welding gun assembly 8 of the present device adopts an existing commercially available product, and the first vertical positioning mechanism 3, the horizontal longitudinal positioning mechanism 5, the second vertical positioning mechanism 6 and the horizontal lateral positioning mechanism 7 respectively adopt linear modules of ball screw nut pairs driven by servo motors, and the first vertical positioning mechanism 3, the horizontal longitudinal positioning mechanism 5 and the horizontal lateral positioning mechanism 7 respectively realize the positioning of the arc fuse additive welding gun assembly 8 in the z direction, the x direction and the y direction. The second vertical positioning mechanism 6 is used to drive the lifting movement of the magnetic pulse strengthening component 1, and completes the process of additive forming and magnetic pulse surface strengthening through the logical coordination with the movement of the arc fuse additive welding gun assembly 8. Therefore, it is necessary to configure a corresponding servo motion control system to realize the corresponding logical control, as well as consumables such as metal wire, to constitute an arc fuse additive device. The control technologies involved are all existing technologies and will not be repeated here. Only the innovations of the present invention are described in detail below.

[0021] Specifically, the first vertical positioning mechanism 3 includes a vertically set first linear module and three first guide rod assemblies, which are fixedly installed at the four corners of the top surface of the base 10 through fixed brackets. The four corners of the top surface of the lifting and positioning plate 4 are fixedly connected with first connecting angle seats, and the vertical section side of the first connecting angle seat is fixedly connected to the side of the positioning platform of the first linear module and the side of the guide block of the three first guide rod assemblies. Under the driving of the first linear module and the guiding action of the three first guide rod assemblies, the vertical lifting and precise positioning of the lifting and positioning plate 4 is realized, thereby realizing the z-direction feeding (i.e., the vertical height increases layer by layer) of the arc fuse additive welding gun assembly 8. A through opening is opened in the middle of the lifting and positioning plate 4, and the additive forming table 2 is located in the through opening, so that the additive forming table 2 will not interfere with the lifting and lowering of the lifting and positioning plate 4.

[0022] The horizontal longitudinal positioning mechanism 5 includes a Figure 1 The second linear module and the second guide rod assembly are arranged in the x direction shown in the figure, the left and right sides of the top surface of the lifting and positioning plate 4 are respectively fixedly connected with the gantry, the second linear module and the second guide rod assembly are respectively fixedly installed on the top of the two gantries, and the side of the positioning platform of the second linear module and the side of the guide block of the second guide rod assembly are respectively fixedly connected with an "L"-shaped bracket. The horizontal lateral positioning mechanism 7 includes a horizontal lateral ( Figure 1 The third linear module is provided in the y direction as shown in the figure, and the two ends of the bottom surface of the third linear module are respectively fixedly connected to the top surfaces of the horizontal sections of the two brackets. An "L"-shaped moving frame is fixedly connected to the top surface of the positioning platform of the third linear module, and the arc fuse additive welding gun assembly 8 is fixedly installed on the side of the vertical section of the moving frame, and the welding gun outlet of the arc fuse additive welding gun assembly 8 is vertically arranged downward.

[0023] The second vertical positioning mechanism 6 includes a fourth linear module and a third guide rod assembly which are vertically set up, and are respectively fixedly mounted on the left and right ends of the top surface of the lifting and positioning plate 4 through fixed brackets. The two ends of the lifting frame plate 9 are respectively fixedly connected to the side of the positioning platform of the fourth linear module and the side of the slider of the third guide rod assembly. Under the driving of the fourth linear module and the guiding action of the third guide rod assembly, the vertical lifting and precise positioning of the lifting frame plate 9 can be driven, thereby realizing the z-direction feeding and retreat of the magnetic pulse strengthening component 1. Since the horizontal longitudinal positioning mechanism 5 and the second vertical positioning mechanism 6 are both fixedly arranged on the lifting and positioning plate 4, the magnetic pulse strengthening component 1 and the arc fuse additive welding gun component 8 are synchronously and equidistantly stepped up. When the magnetic pulse surface strengthening parameters of the magnetic pulse strengthening component 1 remain unchanged, the stroke of the fourth linear module driving the magnetic pulse strengthening component 1 to descend vertically each time is fixed, that is, it is ensured that the relative position of its magnetic pulse surface strengthening working area and the top strengthening area of ​​the workpiece 100 formed by additive deposition layer by layer on the additive forming table 2 is the same during each strengthening process.

[0024] Both sides of the lifting frame plate 9 are "n"-shaped arch structures, which can prevent the lifting frame plate 9 from causing motion interference with the horizontal longitudinal positioning mechanism 5 during the downward movement; the bottom surface of the middle section of the lifting frame plate 9 is fixedly connected to the mounting frame plate 901 by studs, and the magnetic pulse enhancement component 1 is fixedly connected to the bottom surface of the mounting frame plate 901 by screws, which facilitates the assembly and disassembly operations of the magnetic pulse enhancement component 1 on the lifting frame plate 9.

[0025] like Figure 3As shown, the magnetic pulse strengthening component 1 includes a magnetic collector 101 with an inverted cone-shaped hollow structure, a magnetic pulse strengthening coil 102 coaxially arranged on the top surface of the magnetic collector 101, and a strengthening groove matching the top contour of the cross-sectional shape of the workpiece 100 is provided on the bottom surface of the magnetic collector 101. The magnetic pulse strengthening coil 102 is a spiral wire structure, and its two ends are respectively connected to the two output electrodes of the magnetic pulse strengthening power supply module 103. In this embodiment, the workpiece 100 formed by layer-by-layer additive deposition by the arc fuse additive welding gun assembly 8 is a thin-walled tubular part, especially a thin-walled cylindrical tube, so the contour of the strengthening groove is circular, and the cross section matches the cross-sectional shape of the top part of the side wall of the workpiece 100, so that when the magnetic pulse strengthening component 1 is lowered to the working position, the top end of the side wall of the workpiece 100 is located in the strengthening groove, and the top surface and the two side surfaces of the workpiece 100 are respectively arranged in parallel with the bottom surface of the groove and the groove wall surfaces on both sides of the strengthening groove, and gaps are left, as shown in FIG. Figure 4 and Figure 5 Preferably, the gap distances on the three sides are all 1 mm. Figure 5 In the figure, for the workpiece 100, the part below the dotted line is the part to be strengthened, and the part above the dotted line is the part to be strengthened. Since the height of a single layer of additive material in the layer-by-layer additive deposition forming process of the arc fuse additive welding gun assembly 8 is less than the depth of the strengthening groove, each additive layer can undergo multiple magnetic pulse surface strengthening processes, so that the surface strengthening is uniform and sufficient.

[0026] like Figure 4 and Figure 6 As shown, the bottom of the mounting frame plate 901 is fixedly connected with a clamping cylinder 902, and the bottom of the clamping cylinder 902 is detachably connected with a clamping plate 903, the top edge of the magnetic collector 101 is clamped between the clamping plate 903 and the clamping cylinder 902, and the magnetic pulse enhancement coil 102 is located in the clamping cylinder 902. In this embodiment, the clamping cylinder 902 is a cylindrical cylinder, and the upper and lower sections of the side wall are provided with connecting flanges, the upper end flange is fixedly connected to the bottom surface of the mounting frame plate 901 by a bolt pair, and the clamping plate 903 is an annular plate, which is detachably assembled with the lower end flange of the clamping cylinder 902 by a bolt pair or hanging, so as to facilitate the rapid assembly and disassembly of the magnetic pulse enhancement assembly 1. The inner edge of the top surface of the clamping plate 903 is provided with an embedding groove, and the top surface edge of the magnet collector 101 is fixedly provided with a clamping flange, which is embedded in the embedding groove. After the clamping plate 903 and the clamping tube 902 are assembled, the magnet collector 101 is pressed and fixed.

[0027] like Figure 7As shown, the system loop of the magnetic pulse enhanced power module 103 includes a power supply 1031, a capacitor 1032, a capacitor switch 1033, an inductor 1034 and a resistor 1035. One end electrode of the power supply 1031 is connected to one end of the magnetic pulse enhanced coil 102. The other end electrode of the power supply 1031 is connected in series with the inductor 1034 and the resistor 1035 in sequence and then connected to the other end of the magnetic pulse enhanced coil 102. The capacitor 1032 is connected in series with the capacitor switch 1033 and then connected in parallel with the two electrode ends of the power supply 1031. In this embodiment, the maximum discharge energy of the magnetic pulse enhanced power module 103 is 100~150kJ, the capacitance of the capacitor 1032 is 300 μF, and the discharge voltage is 5~20kV. During the arc fuse additive process, the power supply 1031 of the magnetic pulse strengthening device is turned on, the capacitor switch 1033 is turned on, the capacitor 1032 begins to charge, and the current flows through the resistor 1035 and the inductor 1034; as time goes by, the voltage in the capacitor 1032 gradually increases, and the current reaches a maximum; after a layer of additive is completed, the magnetic pulse strengthening device is moved to the top of the side wall of the additively formed workpiece, the capacitor switch 1033 is disconnected, and the capacitor 1032 is discharged, and the electromagnetic field released by the magnetic pulse strengthening coil 102 generates a magnetic field force to impact the top surface of the additively formed workpiece 100, thereby introducing a residual stress field and a certain degree of surface hardening to the surface to improve the fatigue strength of the workpiece.

[0028] See also Figure 8 The present invention also provides a magnetic pulse strengthening process for improving the performance of an additively formed workpiece, which is applied to the magnetic pulse strengthening device for improving the performance of an additively formed workpiece as described above, and comprises the following steps: S1. System initialization and device reset: the second vertical positioning mechanism 6 drives the magnetic pulse enhancement assembly 1 to rise and reset to the top of the area to be added on the additive forming table 2, and the horizontal longitudinal positioning mechanism 5 and the horizontal lateral positioning mechanism 7 drive the arc fuse additive welding gun assembly 8 to move horizontally and reset to the top side of the area to be added on the additive forming table 2.

[0029] Before the system is initialized, the metal wire and other consumables are installed on the arc fuse additive welding gun assembly 8. After the system is initialized, the device is debugged as necessary to ensure that the motion system and control of the arc fuse additive welding gun assembly 8 and each positioning mechanism work properly. At the same time, the system circuit of the magnetic pulse enhanced power supply module 103 is powered on to ensure normal use.

[0030] S2, arc fuse single-layer additive: The motion control system starts the horizontal longitudinal positioning mechanism 5 and the horizontal transverse positioning mechanism 7 to drive the arc fuse additive welding gun assembly 8 to move to the area to be added on the additive forming table 2, and drives the arc fuse additive welding gun assembly 8 to move according to the preset forming route. The arc welder in the arc fuse additive welding gun assembly 8 heats and melts the metal wire to form a molten pool. The high temperature generated by the welding arc causes the metal wire to be in a molten state before contacting the base 10 (the bottom layer of additive) or the previous layer. The welding gun of the arc fuse additive welding gun assembly 8 squeezes out the molten metal during the movement, and the molten metal is deposited and formed to form a layer of the required structure according to the preset forming route. Then, the horizontal longitudinal positioning mechanism 5 and the horizontal transverse positioning mechanism 7 drive the arc fuse additive welding gun assembly 8 to move and reset, completing the single-layer additive process.

[0031] S3, magnetic pulse surface strengthening: During the process of arc fuse additive, the capacitor 1032 completes the charging process. After completing the single-layer additive, the second vertical positioning mechanism 6 drives the magnetic pulse strengthening component 1 to move down to the top outer side of the additively formed workpiece 100, the capacitor switch 1033 is disconnected, the capacitor 1032 is discharged, and the electromagnetic field released by the magnetic pulse strengthening coil 102 generates a magnetic field force to impact the top surface of the additively formed workpiece 100 for impact strengthening. After the preset impact strengthening time (0.001~1ms in this embodiment), the second vertical positioning mechanism 6 drives the magnetic pulse strengthening component 1 to rise and reset.

[0032] S4, additive height feeding: the first vertical positioning mechanism 3 drives the arc fuse additive welding gun assembly 8 to move up a single layer additive height to achieve step feeding in the z direction.

[0033] S5, cyclic additive and strengthening process: repeat the above steps S2 to S4 to complete the additive deposition forming process of the workpiece 100 on the additive forming table 2 layer by layer, and after each layer of additive deposition forming, complete the impact strengthening of the top surface of the workpiece 100.

[0034] S6. Removing the sample: After the last magnetic pulse surface impact strengthening is completed, the power supply of the device is disconnected to stop the device from working, and the additively formed workpiece 100 is removed from the additive forming table 2 after cooling to room temperature.

[0035] For the machined workpiece 100, the relationship between the magnetic pulse strengthening parameters and the grain size, metallurgical defects and residual stress is determined through metallographic observation and residual stress detection, providing a control basis for further magnetic pulse strengthening microstructure control and residual stress control.

[0036] In the simulation software, the above magnetic pulse surface impact strengthening process is simulated, and finally the distribution of the surface equivalent stress of the additive workpiece after magnetic pulse strengthening is obtained, such as Fig. 9 and Fig.10 As shown in the simulation results, it can be seen that when the additive workpiece is strengthened by magnetic pulse, its top surface is subjected to a large impact force, and the side surface is also subjected to a certain pressure due to the special structure of the magnetic collector, which ensures the integrity of the workpiece as a whole and has a certain depth of the affected layer to achieve the purpose of improving performance.

[0037] Obviously, the anisotropic magnetic collector can be designed into a variety of shapes to meet the application needs of the magnetic pulse surface impact strengthening process for additive workpieces with different cross-sectional shapes (not limited to cylindrical barrels).

[0038] Embodiment 2: See also Fig.11 and Fig.12 The difference between this embodiment and the first embodiment is that the outer shape of the magnetic collector 101 is a hollow quadrangular pyramid structure, the cross-section of the strengthening groove is a rectangular horizontal groove, which runs through both ends of the bottom surface of the magnetic collector 101, the pulse strengthening coil 102 is correspondingly a rectangular spiral disk structure, the clamping tube 902 and the clamping pressure plate 903 are correspondingly hollow square frame structures, and the remaining structures are basically the same as those in the first embodiment.

[0039] In specific use, the workpiece 100 formed by the layer-by-layer additive deposition of the arc fuse additive welding gun assembly 8 is a thin plate, especially a thin plate with a rectangular cross-section, so the cross-section of the strengthening groove matches the cross-sectional shape of the top portion of the side wall of the workpiece 100, so that when the magnetic pulse strengthening assembly 1 is lowered to the working position, the top end of the side wall of the workpiece 100 is located in the strengthening groove, and the top surface and the two side surfaces of the workpiece 100 are respectively arranged in parallel with the bottom surface of the strengthening groove and the groove wall surfaces on both sides, and gaps are left, such as Fig.11 and Fig.12 As shown. Preferably, the gap distances on the three sides are all 1 mm. Since the height of a single layer of additive material is less than the depth of the strengthening groove during the layer-by-layer additive deposition forming process of the arc fuse additive welding gun assembly 8, each additive layer can undergo multiple magnetic pulse surface strengthening processes, so that the surface strengthening is uniform and sufficient.

[0040] Similarly, for the machined workpiece 100, the relationship between the magnetic pulse strengthening parameters and the grain size, metallurgical defects and residual stress is determined through metallographic observation and residual stress detection, providing a control basis for further magnetic pulse strengthening microstructure control and residual stress control.

[0041] In the simulation software, the above magnetic pulse surface impact strengthening process is simulated, and finally the distribution of the surface equivalent stress of the additive workpiece after magnetic pulse strengthening is obtained, such as Fig.13 and Fig.14As shown in the simulation results, it can be seen that since the central strengthening part of the additive workpiece is a solid structure, which is different from the hollow cylindrical structure of the first embodiment, when the additive workpiece is strengthened by magnetic pulse, the impact force on the center of its top surface is larger than that on both sides, but the side surfaces are also subject to a certain pressure due to the special structure of the magnetic collector, which ensures the integrity of the workpiece as a whole and has a certain depth of the affected layer to achieve the purpose of improving performance.

[0042] The present invention innovatively applies electromagnetic forming technology to the post-processing of the WAAM process, and utilizes the RLC circuit discharge process coil to generate a magnetic field, so that a magnetic field force is generated inside the workpiece to achieve plastic deformation of the workpiece surface. In the additive process, the RLC circuit is charged and then discharged to achieve magnetic pulse strengthening, saving working time and improving efficiency; for the magnetic pulse strengthening process, its strain rate is high and the energy released is large, so it has a higher depth of the affected layer; there is no contact, and the surface quality of the formed workpiece is relatively good. In addition, high-frequency magnetic pulse strengthening can also refine the grains and eliminate microscopic void defects, thereby improving the mechanical properties and uniformity of the material. Since the workpiece will be subjected to a large electromagnetic force during the magnetic pulse strengthening process, in order to avoid a large deformation of the workpiece during this process, the shape of the magnetizer is designed so that the workpiece can be subjected to compressive stress on the side while being subjected to the top impact. While ensuring that the shape of the workpiece does not change too much, it is subjected to three-way compressive stress and improves the mechanical properties.

[0043] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A magnetic pulse strengthening device for improving the performance of additively formed workpieces, characterized in that: It comprises a base, an additive forming table fixedly arranged on the top surface of the base, and a first vertical positioning mechanism, the positioning output end of the first vertical positioning mechanism is fixedly connected with a lifting positioning plate sleeved on the outside of the additive forming table, the top surface of the lifting positioning plate is respectively fixedly provided with a horizontal longitudinal positioning mechanism and a second vertical positioning mechanism, the positioning output end of the horizontal longitudinal positioning mechanism is fixedly connected with a horizontal transverse positioning mechanism, the positioning output end of the horizontal transverse positioning mechanism is fixedly connected with an arc fuse additive welding gun assembly located above the top surface of the additive forming table, the positioning output end of the second vertical positioning mechanism is fixedly connected with a lifting frame plate, and the bottom of the lifting frame plate is provided with a magnetic pulse strengthening assembly located just above the top surface of the additive forming table; The arc fuse additive welding gun assembly additively deposits and forms the workpiece layer by layer on the additive forming table. After each layer of additive deposition is completed, the magnetic pulse strengthening assembly is positioned to the outside of the top of the additively formed workpiece, and the magnetic pulse strengthening assembly impact-strengthens the top surface of the workpiece through the magnetic field force.

2. A magnetic pulse strengthening device for improving the performance of additively formed workpieces according to claim 1, characterized in that: The magnetic pulse enhancement component includes a magnetic collector with an inverted cone-shaped hollow structure and a magnetic pulse enhancement coil coaxially arranged on the top surface of the magnetic collector. A strengthening groove matching the top contour of the cross-sectional shape of the workpiece is provided on the bottom surface of the magnetic collector. The magnetic pulse enhancement coil is a spiral wire structure, and its two ends are respectively connected to the two output electrodes of the magnetic pulse enhancement device.

3. A magnetic pulse strengthening device for improving the performance of additively formed workpieces according to claim 2, characterized in that: The system circuit of the magnetic pulse enhancement device includes a power supply, a capacitor, a capacitor switch, an inductor and a resistor. One end electrode of the power supply is connected to one end of the magnetic pulse enhancement coil, the other end electrode of the power supply is connected in series with the inductor and the resistor in sequence and then connected to the other end of the magnetic pulse enhancement coil. The capacitor is connected in series with the capacitor switch and then connected in parallel with the two electrode ends of the power supply.

4. A magnetic pulse strengthening device for improving the performance of an additively formed workpiece according to claim 3, characterized in that: The maximum discharge energy of the magnetic pulse enhancement device is 100~150kJ, the capacitance of the capacitor is 160~320 μF, and the discharge voltage is 5~20kV.

5. The magnetic pulse strengthening device for improving the performance of additively formed workpieces according to claim 2, characterized in that: The bottom of the lifting frame plate is fixedly connected to a mounting frame plate, the bottom of the mounting frame plate is fixedly connected to a clamping cylinder, the bottom of the clamping cylinder is detachably connected to a clamping pressure plate, the top surface edge of the magnetic collector is clamped between the clamping pressure plate and the clamping cylinder, and the magnetic pulse enhancement coil is located in the clamping cylinder.

6. A magnetic pulse strengthening process for improving the performance of an additively formed workpiece, applied to a magnetic pulse strengthening device for improving the performance of an additively formed workpiece as claimed in any one of claims 2 to 5, characterized in that: The following steps are involved: S1, the magnetic pulse strengthening assembly rises and resets to the top of the area to be added, and the arc fuse additive welding gun assembly moves horizontally and resets to the top side of the area to be added; S2, the arc fuse additive welding gun assembly moves to the area to be added, moves according to the preset forming route, and moves and resets after completing the single-layer molten metal deposition forming; S3, the magnetic pulse strengthening component moves down to the top outer side of the additively formed workpiece, and the top surface of the workpiece is impact strengthened by the magnetic field force. After the preset impact strengthening time, the magnetic pulse strengthening component rises and resets; S4, the arc fuse additive welding gun assembly moves up a single-layer additive height; S5, cyclic additive and strengthening process: repeating steps S2 to S4 to complete the additive deposition forming of the workpiece layer by layer on the additive forming table and the impact strengthening of the top surface; S6. The device stops working, and the additively formed workpiece is removed from the additive forming table after cooling to room temperature.

7. A magnetic pulse strengthening process for improving the performance of additively formed workpieces according to claim 6, characterized in that: In step S3, the distance between the side surface of the strengthening groove on the bottom surface of the magnetic collector and the top outer surface of the additively formed workpiece is 0.5-2 mm, and the preset impact strengthening time is 0.001-1 ms.

8. A magnetic pulse strengthening process for improving the performance of additively formed workpieces according to claim 6 or 7, characterized in that: After step S6, the relationship between the magnetic pulse strengthening parameters and the grain size, metallurgical defects and residual stress is determined through metallographic observation and residual stress detection.

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