Ultrasonic assisted electro-discharge jet deposition repair method and electrode

Abstract

The application provides an ultrasonic wave assisted electric spark jet deposition repairing method, a metal workpiece defect surface is coated by using an electric spark deposition gun, an ultrasonic wave generator is used to vibrate an electric spark deposition electrode, and process parameters of the ultrasonic wave generator and process parameters of the electric spark deposition electrode are disclosed. The application also discloses an ultrasonic wave assisted electric spark jet deposition repairing electrode which can be used in the above method. The ultrasonic wave assisted electric spark jet deposition repairing method has the advantages of fast molten drop transition speed, small quality and good transition stability, greatly improves the molten quality transition efficiency of the material interelectrode transfer process, and the fragmented molten drop increases the contact area with the base body molten pool, which is more conducive to the combination of the coating and the base body.

Description

Technical Field

[0001] This invention relates to workpiece defect repair technology, and more particularly to an ultrasonic-assisted electrical discharge jet deposition repair method and electrode. Background Technology

[0002] In high-end equipment in fields such as aerospace, transportation, energy and chemical engineering, and equipment manufacturing, key components often possess characteristics such as high precision, high strength, high temperature resistance, and wear resistance due to the special requirements of their uses, functions, and operating environments. Furthermore, their application in various special working conditions imbues them with individuality and complexity. Therefore, the repair and remanufacturing of these critical components' failed surfaces places higher demands on aspects such as coating surface quality, bonding strength, and the contact and friction properties of the coating.

[0003] Electrical discharge deposition (EDD) is a special surface repair and strengthening process that utilizes the localized high-temperature plasma of pulsed spark discharge to melt tool electrode materials and transfer and solidify them onto the substrate surface to form a coating. As an advanced surface engineering technology, it is widely used in the remanufacturing of failed surfaces of critical components. Compared to other commonly used surface technologies, EDD has advantages such as a small heat-affected zone (no preheating required), low residual stress and deformation in the coating, simple electrode manufacturing with a wide range of material options, and the ability to achieve a truly high-strength metallurgical bond between the substrate and the coating (bonding strength can reach over 500 MPa). It is particularly suitable for repairing failed surfaces of critical components operating in complex and harsh environments characterized by high stress, high temperature, and easy wear.

[0004] Currently, due to the uncertainties in the electrical discharge machining process, there are many voids and microcracks inside and on the surface of the deposited layer, which leads to certain defects in improving surface quality, reducing tool wear, and the bonding strength between the electrode material and the substrate material. Summary of the Invention

[0005] The purpose of this invention is to address the issue of insufficient surface quality in traditional electrical discharge deposition processes by proposing an ultrasonic-assisted electrical discharge jet deposition repair method. The coating obtained using this method exhibits strong adhesion, minimal tool wear, excellent surface quality, and fewer voids and microcracks.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: an ultrasonic-assisted electrical discharge jet deposition repair method, wherein an electrical discharge jet gun is used to deposit coating on the defective surface of a metal workpiece, and an ultrasonic generator is used to vibrate the electrical discharge jet deposition electrode.

[0007] Furthermore, the process parameters of the ultrasonic generator are as follows: operating frequency 20±1KHz, maximum power 2600W, power adjustable within the range of 0 to 100%, within the allowable range, the amplitude variation range of the ultrasonic welding vibration system in the resonant state is 7μm-23μm, and the rated voltage is AC220 50Hz.

[0008] Furthermore, the process parameters for the electrical discharge deposition electrode are: input power AC 200V, power 1000W, voltage 20-100V, frequency 50-500Hz, and output percentage 20-100%.

[0009] Furthermore, the ultrasonic-assisted electrospark jet deposition repair method includes the following steps:

[0010] Step (1) Turn on the three-axis motion control system to move the electrical discharge deposition gun above the deposition area of ​​the defective workpiece; turn on the electrical discharge deposition power supply and adjust the process parameters of the electrical discharge deposition electrode; turn on the ultrasonic power supply and adjust the process parameters of the ultrasonic generator.

[0011] In step (2), the discharge heat of the electric spark deposition electrode melts the electrode material and deposits it onto the surface of the workpiece. During the transition deposition, the ultrasonic radiation force is transmitted to the end of the deposition electrode. According to the capillary theory, the droplet is subjected to the acoustic radiation force. When the acoustic radiation force is greater than the surface tension of the droplet, the droplet breaks and sprays out, and undergoes uniform metallurgical bonding with the molten defective workpiece surface material to form an alloy deposition layer.

[0012] Furthermore, the acoustic radiation force of the ultrasonic wave is transmitted to the end of the deposition electrode through the ER sleeve connecting shaft, ER sleeve, and ER clamp.

[0013] Another objective of this invention is to disclose an ultrasonic-assisted electrical spark jet deposition repair electrode, comprising: an ultrasonic generator, a flange, an ER sleeve connecting shaft, an ER sleeve, a deposition electrode, threaded bolts, and an ER sleeve.

[0014] The ultrasonic generator is fitted with a flange in the middle, and the bottom of the ultrasonic generator is coaxially fixed with the ER sleeve connecting shaft; the ER sleeve is fitted on the end of the ER sleeve connecting shaft away from the ultrasonic generator; the ER collet is embedded in the ER sleeve connecting shaft and the ER sleeve, and the electro-spark deposition electrode is installed in the inner hole of the ER collet.

[0015] Furthermore, the bottom of the ultrasonic generator is coaxially fixed to the ER sleeve connecting shaft by threaded bolts.

[0016] Furthermore, an alumina matching layer is provided on the ER sleeve connecting shaft to serve as insulation.

[0017] Furthermore, the bottom of the ultrasonic generator is fixed with a zirconia screw, which serves as an insulator.

[0018] Furthermore, the ER sleeve is threadedly fitted to the ER sleeve connecting shaft.

[0019] The ultrasonic-assisted electrospark jet deposition repair method and electrode of this invention have the following advantages compared with the prior art:

[0020] This invention combines an ultrasonic-electro-spark jet deposition device to perform deposition repair on defective metals. During the deposition process, due to the short contact time (10 minutes)... -6 ~10 -5 s. The current density flowing through it is large, 10⁵ to 10⁶ A / cm² 2 This process creates a high-temperature, high-pressure micro-region on the substrate surface, reaching temperatures instantaneously between 8000 and 25000°C. Under this instantaneous high temperature and pressure, some material at the contact point melts, vaporizes, or plasmas, penetrating into the substrate surface. Based on this, the ultrasonic radiation force acts on the deposition electrode, causing the molten droplets to spray out, thus achieving a uniform bond between the sprayed droplets and the molten pool. This results in a coating with strong adhesion between the sprayed droplets and the defective metal, a dense microstructure, fewer defects, and a large coating thickness.

[0021] In summary, the ultrasonic-assisted electrosparking deposition repair method provided by this invention has the advantages of fast droplet transfer speed, small mass, and better transfer stability, which greatly improves the melt transfer efficiency of the material interelectrode transfer process. At the same time, the fragmented droplets increase the contact area with the substrate molten pool, which is more conducive to the bonding between the coating and the substrate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the ultrasonic-assisted electrospark jet deposition repair electrode of the present invention;

[0023] Figure 2 This is a cross-sectional view of the deposition electrode clamping portion of the present invention;

[0024] Figure 3 This is a schematic diagram illustrating the principle of droplet ejection in the electro-spark deposition electrode of the present invention.

[0025] Figure 4 This is a schematic diagram of an example process of the ultrasonic-assisted electrical spark jet deposition method of the present invention.

[0026] Wherein: 101-Ultrasonic generator, 102-Flange, 103-ER collet connecting shaft, 104-ER collet, 105-Deposited electrode, 106-Threaded bolt, 107-ER collet. Detailed Implementation

[0027] To make the technical problems solved by this invention, the technical solutions adopted, and the technical effects achieved clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the invention and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings, not all of them. In the description of this patent application, terms such as "left," "right," "front and back," and "up and down" are directional concepts referring to the position shown in the image, and not specific directions.

[0028] The present invention will be further described below with reference to the embodiments:

[0029] Example 1

[0030] This embodiment discloses an ultrasonic-assisted electrospark jet deposition remediation method, such as... Figure 4 As shown.

[0031] like Figure 1 , Figure 2 As shown in the cross-sectional view, one end of the ER sleeve connecting shaft 103 is installed at the end of the ultrasonic generator 101 and connected by a threaded bolt 106; the ER sleeve 104 is threadedly connected to the other end of the ER sleeve connecting shaft 103; the ER clamp 107 is disposed inside the ER sleeve connecting shaft 103 and the ER sleeve 104; and the deposition electrode 105 is installed in the inner hole of the ER clamp 107.

[0032] like Figure 3 As shown, this is a schematic diagram illustrating the principle of droplet jetting in electrical discharge deposition (EDD) processing.

[0033] In this embodiment, the ultrasonic generator 101 generates ultrasonic radiation force at its end. Through the tight connection of the ER sleeve connecting shaft 103, ER sleeve 104, and ER clamp 107, the radiation force is transmitted to the deposition electrode 105. During electrical discharge machining, due to the short contact time (10 minutes)... -6 ~10 -5 s. The current density flowing through it is large, 10⁵ to 10⁶ A / cm² 2This process creates a high-temperature, high-pressure micro-region on the substrate surface, reaching temperatures instantaneously between 8000 and 25000°C. Under this instantaneous high temperature and pressure, some material at the contact point melts and penetrates into the substrate surface. Then, through the excitation of external high-energy ultrasonic vibration, a strong and persistent disturbance is generated in the molten material, disrupting the balance between its surface tension and viscous forces. This causes the surface of the molten droplets to rupture, resulting in droplet fragmentation and high-speed impact with the molten pool in a jetting manner. This achieves a uniform bonding between the jetted droplets and the molten pool, resulting in a coating with strong adhesion, dense microstructure, fewer defects, and greater coating thickness, thus improving repair accuracy and microstructural properties.

[0034] This invention utilizes ultrasound as an external control device in the electrical discharge deposition process. Ultrasonic vibration has advantages such as strong energy transmission penetration, fast response speed, and controllable intensity and direction. Therefore, applying ultrasonic vibration to the deposition electrode generates ultrasonic excitation on the molten material of the electrical discharge deposition electrode, serving as an external driving force for the inter-electrode transition of the molten droplets. This excites the jet transition of the molten droplets, thereby improving the speed and efficiency of the droplet transition, ensuring the stability of the material transfer process, and significantly enhancing the uniform bonding between the molten droplets and the molten pool, thus improving processing quality.

[0035] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for ultrasonic-assisted electrospark jet deposition remediation, characterized in that, The surface of the metal workpiece defect is deposited with an electrical discharge deposition gun, and the electrical discharge deposition electrode is vibrated by an ultrasonic generator. The ultrasonic-assisted electrospark jet deposition remediation method includes the following steps: Step (1) Turn on the three-axis motion control system to move the electrical discharge deposition gun above the deposition area of ​​the defective workpiece; turn on the electrical discharge deposition power supply and adjust the process parameters of the electrical discharge deposition electrode; turn on the ultrasonic power supply and adjust the process parameters of the ultrasonic generator. In step (2), the discharge heat of the electrode in the electro-spark deposition electrode melts the electrode material and deposits it onto the surface of the workpiece. During the transition deposition, the ultrasonic radiation force transmits the vibration to the end of the deposition electrode, causing the droplets to break and spray out, and to form a uniform metallurgical bond with the molten defective workpiece surface material, thus forming an alloy deposition layer. The ultrasonic-assisted electrical spark jet deposition repair method uses an ultrasonic-assisted electrical spark jet deposition repair electrode including: an ultrasonic generator (101), a flange (102), an ER sleeve connecting shaft (103), an ER sleeve (104), a deposition electrode (105), a threaded bolt (106), and an ER sleeve (107). The ultrasonic generator (101) is fitted with a flange (102) in the middle, and the bottom of the ultrasonic generator (101) is coaxially fixed with the ER sleeve connecting shaft (103); the ER sleeve (104) is fitted on the end of the ER sleeve connecting shaft (103) away from the ultrasonic generator (101); the ER collet (107) is embedded in the ER sleeve connecting shaft (103) and the ER sleeve (104), and the electro-spark deposition electrode (105) is installed in the inner hole of the ER collet (107); An alumina matching layer is provided on the ER sleeve connecting shaft (103); The bottom of the ultrasonic generator (101) is fixed by zirconia screws.

2. The ultrasonic-assisted electrospark jet deposition remediation method according to claim 1, characterized in that, The process parameters of the ultrasonic generator are as follows: working frequency 20±1KHz, maximum power 2600W, power adjustable within the range of 0~100%, within the allowable range, the amplitude variation range of the ultrasonic welding vibration system in the resonant state is 7μm-23μm, and the rated voltage is AC220 50Hz.

3. The ultrasonic-assisted electrospark jet deposition remediation method according to claim 1, characterized in that, The process parameters for the electrical discharge deposition electrode are: input power AC 200V, power 1000W, voltage 20-100V, frequency 50-500Hz, and output percentage 20-100%.

4. The ultrasonic-assisted electrospark jet deposition remediation method according to claim 1, characterized in that, The bottom of the ultrasonic generator (101) is coaxially fixed to the ER sleeve connecting shaft (103) by a threaded bolt (106).

5. The ultrasonic-assisted electrospark jet deposition remediation method according to claim 1, characterized in that, The ER sleeve (104) is threadedly engaged with the ER sleeve connecting shaft (103).

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