Research on discharge characteristics of working mediums of electric discharge machining

2020 ◽  
Vol 235 (1-2) ◽  
pp. 34-40
Author(s):  
Min Li ◽  
Lanrong Cai ◽  
Junling Zhao
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Base Material ◽  
Deionized Water ◽  
Water Medium ◽  
Discharge Process ◽  
Dry Powder ◽  
Discharge Characteristics ◽  
Mixed Medium ◽  
Tc4 Alloy

Successful surface modification can be obtained by Electrical Discharge Machining (EDM). In this work the discharge characteristics in misted deionized water and near-dry powder-mixed medium was studied systematically, as well as the microstructure and properties of electrical discharge strengthened layers on TC4 alloy. It indicates that the breakdown voltage of EDM in misted deionized water medium has been reduced to about 1/3 than in air medium. In near-dry powder-mixed medium, it is reduced to about 1/9, because the discharge gap is much larger than that of other mediums. In other words, a stable discharge can be obtained by larger discharge gaps and lower pulse energy than traditional EDM surface strengthening method, which leads to more stable discharge process. Experimental researches show that dense and sound combination with matrix like, multiphase hybrid intensification and chrysanthemum petal-like microstructure of strengthened layers can be observed in the near-dry powder-mixed medium. Meanwhile, it is found that the microhardness of the strengthened layer is up to about 1200 HV, which is four times higher than the base material.

scholarly journals Sub-Microstructure of Surface and Subsurface Layers after Electrical Discharge Machining Structural Materials in Water

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1040
Author(s):  
Sergey N. Grigoriev ◽  
Marina A. Volosova ◽  
Anna A. Okunkova ◽  
Sergey V. Fedorov ◽  
Khaled Hamdy ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Structural Materials ◽  
12Kh18n10t Steel ◽  
Mean Deviation ◽  
Water Medium ◽  
Tool Electrode ◽  
Marquardt Algorithm ◽  
Subsurface Layers ◽  
Electrical Wear

The material removal mechanism, submicrostructure of surface and subsurface layers, nanotransformations occurred in surface and subsurface layers during electrical discharge machining two structural materials such as anti-corrosion X10CrNiTi18-10 (12kH18N10T) steel of austenite class and 2024 (D16) duralumin in a deionized water medium were researched. The machining was conducted using a brass tool of 0.25 mm in diameter. The measured discharge gap is 45–60 µm for X10CrNiTi18-10 (12kH18N10T) steel and 105–120 µm for 2024 (D16) duralumin. Surface roughness parameters are arithmetic mean deviation (Ra) of 4.61 µm, 10-point height (Rz) of 28.73 µm, maximum peak-to-valley height (Rtm) of 29.50 µm, mean spacing between peaks (Sm) of 18.0 µm for steel; Ra of 5.41 µm, Rz of 35.29 µm, Rtm of 43.17 µm, Sm of 30.0 µm for duralumin. The recast layer with adsorbed components of the wire tool electrode and carbides was observed up to the depth of 4–6 µm for steel and 2.5–4 µm for duralumin. The Levenberg–Marquardt algorithm was used to mathematically interpolate the dependence of the interelectrode gap on the electrical resistance of the material. The observed microstructures provide grounding on the nature of electrical wear and nanomodification of the obtained surfaces.

Machining Feasibility of a New Developed Medium in Electrical Discharge Machining

2015 ◽  
Vol 656-657 ◽  
pp. 335-340 ◽  
Author(s):  
Fang Pin Chuang ◽  
Yan Cherng Lin ◽  
Hsin Min Lee ◽  
Han Ming Chow ◽  
A. Cheng Wang
Keyword(s):  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Environmentally Friendly ◽  
Industrial Applications ◽  
Deionized Water ◽  
Machining Parameters ◽  
Machining Performance ◽  
Machining Characteristics

The environment issue and green machining technique have been induced intensive attention in recent years. It is urgently need to develop a new kind dielectric to meet the requirements for industrial applications. The aim of this study is to develop a novel dielectric using gas media immersed in deionized water for electrical discharge machining (EDM). The developed machining medium for EDM can fulfill the environmentally friendly issue and satisfy the demand of high machining performance. The experiments were conducted by this developed medium to investigate the effects of machining parameters on machining characteristics in terms of material removal rate (MRR) and surface roughness. The developed EDM medium revealed the potential to obtain a stabilizing progress with excellent machining performance and environmentally friendly feature.

Crack-Less Electrical Discharge Machining of Molybdenum with Titanium Electrode

2014 ◽  
Vol 510 ◽  
pp. 101-105 ◽  
Author(s):  
Kaneko Kensei ◽  
Furutani Katsushi
Keyword(s):  
High Temperature ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Base Material ◽  
Negative Electrode ◽  
High Hardness ◽  
Recast Layer ◽  
Recrystallization Temperature ◽  
High Temperature Strength ◽  
Electrode Polarity

This paper describescrack-less electrical discharge machining (EDM) of molybdenum (Mo) with titanium (Ti) electrode. Mo is often machined by EDM because of its high hardness. However, a molybdenum carbide (MoC and Mo2C) layer with high hardness and brittleness is formed by EDM in kerosene oil. Moreover, Mo becomes recrystallizationembrittlement at high temperature. Therefore, many cracks occurred in the EDMed surface. On the other hand, the addition of Ti rises recrystallization temperature and improves high temperature strength of Mo.In order to decrease the cracks in the machined surface, Mo was machined by EDM with a Ti electrode in deionized water. In the case of the positive electrode polarity, many cracks occurred in the base material and recast layer. The cracks in the base material might generate by crystal grain boundary embrittlement. In contrast, the EDMed surface indicated crack-less on the negative electrode polarity. To clarify the causes of crack-less surface on negative electrode polarity, componential analysis of EDMed surface was carried out. The component ratio of Ti on the negative electrode polarity was higher than that on the positive. In addition, the recast layer was composed by Mo-Ti solid solution.

scholarly journals Study of Micro Structural Material Changes after WEDM Based on TEM Lamella Analysis

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 949 ◽  
Author(s):  
Katerina Mouralova ◽  
Radim Zahradnicek ◽  
Libor Benes ◽  
Tomas Prokes ◽  
Radim Hrdy ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Subsurface Layer ◽  
Base Material ◽  
Wire Electrical Discharge Machining ◽  
Transmission Electron ◽  
Machined Parts ◽  
Tem Lamella ◽  
Unconventional Machining

Wire electrical discharge machining is an unconventional machining technology that is crucial in many industries. The surface quality of the machined parts is carefully monitored, but the condition of the subsurface layer also plays a crucial role, especially in case of defects occurrence such as cracks or burnt cavities. The subsurface layer of individual materials is affected differently due to wire electrical discharge machining. For this reason, this study was carried out focusing on a detailed analysis of transmission electron microscope (TEM) lamella made of Ti-6Al-4V titanium alloy, AlZn6Mg2Cu aluminum alloy, pure molybdenum, Creusabro 4800 steel, and Hardox 400 steel. The attention was first of all paid to the concentration and distribution of individual elements in the recast layer and also in the base material, which was often affected by wire electrical discharge machining. Further, a diffraction analysis was performed for each TEM lamella in the adhesive area and in the base material area. In order to assess the macro-effects on the machined material, the topography analysis of the machined surfaces and the morphology analysis were performed using electron microscopy.

Effects of hybrid Al2O3- SiO2 nanoparticles in deionized water on the removal rate and surface roughness during electrical discharge machining of Ti-6Al-4V

2021 ◽  
pp. 095440892110593
Author(s):  
Saeed Oskueyan ◽  
Vahid Abedini ◽  
Alireza Hajialimohamadi
Keyword(s):  
Discharge Current ◽  
Electrical Discharge ◽  
Silicon Oxide ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Sio2 Nanoparticles ◽  
Deionized Water ◽  
Relative Composition ◽  
Maximum Value ◽  
Pulse On Time

Nowadays, special attention is paid to the application of nanoparticles to improve the performance of Electrical Discharge Machining (EDM). In this paper, modeling and optimizing the process parameters of Nanopowder Mixed Electrical Discharge Machining (NPMEDM) is studied. In this study, the effect of aluminum oxide (Al2O3) and silicon oxide (SiO2) nanoparticles on the deionized water dielectric is investigated simultaneously in the process of electrical discharge machining of Ti-6Al-4V alloy. After analyzing the parameters, the discharge current, concentration, pulse on time, and relative composition are considered as input factors. Response Surface Methodology (RSM) using Design-Expert software is employed for the design of the experiments, analysis of the results, and optimization of the parameters. The results show that the best surface morphology is obtained by machining with the addition of nanoparticles in the relative composition of 50%. In this percentage of the composition, the surface of the workpiece has the least value of crack and recast layer. In addition, the maximum value of the material removal rate (MRR) and minimum value of tool wear rate (TWR) can be achieved in the discharge current of 12 A, pulse on-time of 100 μs, and relative composition of 75% Al2O3 – 25% SiO2.

scholarly journals Elemental and Thermochemical Analyses of Materials after Electrical Discharge Machining in Water: Focus on Ni and Zn

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3189
Author(s):  
Sergey N. Grigoriev ◽  
Marina A. Volosova ◽  
Anna A. Okunkova ◽  
Sergey V. Fedorov ◽  
Khaled Hamdy ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
12Kh18n10t Steel ◽  
Water Medium ◽  
Nickel Steel ◽  
Intermetallic Compound Formation ◽  
Electrical Erosion ◽  
Materials Used ◽  
First Time

The mechanism of the material destruction under discharge pulses and material removal mechanism based on the thermochemical nature of the electrical erosion during electrical discharge machining of conductive materials were researched. The experiments were conducted for two structural materials used in the aerospace industry, namely austenite anticorrosion X10CrNiTi18-10 (12kH18N10T) steel and 2024 (D16) duralumin, machined by a brass tool of 0.25 mm in diameter in a deionized water medium. The optimized wire electrical discharge machining factors, measured discharge gaps (recommended offset is 170–175 µm and 195–199 µm, respectively), X-ray photoelectron spectroscopy for both types of materials are reported. Elemental analysis showed the presence of metallic Zn, CuO, iron oxides, chromium oxides, and 58.07% carbides (precipitation and normal atmospheric contamination) for steel and the presence of metallic Zn, CuO, ZnO, aluminum oxide, and 40.37% carbides (contamination) for duralumin. For the first time, calculating the thermochemistry parameters for reactions of Zn(OH)2, ZnO, and NiO formation was produced. The ability of Ni of chrome–nickel steel to interact with Zn of brass electrode was thermochemically proved. The standard enthalpy of the Ni5Zn21 intermetallic compound formation (erosion dust) ΔH0298 is −225.96 kJ/mol; the entropy of the crystalline phase Scint is 424.64 J/(mol·K).

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