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 ◽  
...  

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.

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3189
Author(s):  
Sergey N. Grigoriev ◽  
Marina A. Volosova ◽  
Anna A. Okunkova ◽  
Sergey V. Fedorov ◽  
Khaled Hamdy ◽  
...  

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).


2008 ◽  
Vol 381-382 ◽  
pp. 451-454
Author(s):  
Atsutoshi Hirao ◽  
S. Tai ◽  
H. Takezawa ◽  
Naotake Mohri ◽  
Kazuro Kageyama ◽  
...  

In electrical discharge machining (EDM), an electrical discharge occurs between a tool electrode and a work-piece, and removal of materials is carried out by vaporized explosion between the electrode and the work-piece. However, the mechanism of material removal in EDM is not well understood. In order to clarify this issue, the acoustic emission (AE) method has been applied to examine the force of explosion, and the Schlieren visualization method has been applied to observe the explosion. In this study, we investigate the effect of discharge current behavior on the occurrence of the AE waves by means of an optical fiber vibration sensor.


2019 ◽  
Vol 969 ◽  
pp. 644-649
Author(s):  
Rakesh Kumar ◽  
Anand Pandey ◽  
Pooja Sharma

Inconel-718 is a nickel based super alloy (difficult-to-cut material) used in aerospace industry. Analysis of machining performances viz. Over Cut (OC) & Surface Roughness (SR) for Inconel-718 through rotary Cu-pin tool electrode have been carried out. Peak current (Ip), pulse-on time (Ton), tool rotation (Nt) & hole depth (h) were used as input factors in Electrical Discharge Drilling (EDD) of Inconel-718 work-piece. Effect of input parameters on performance characteristics like OC & SR were found by Taguchi’s L9 (34) orthogonal array. It is reveals that Ip & h are most affecting factors that affects OC & SR. The Scanning Electron Microscope image was used to measure diameter of hole on work-piece after machining.


Author(s):  
Ranjit Singh ◽  
Ravi Pratap Singh ◽  
Rajeev Trehan

Shape memory alloys (SMAs) have been well known for their superior and excellent properties which makes them an eligible candidate of paramount importance in real-life industrial applications such as; orthopedic implants, actuators, micro tools, stents, coupling and sealing elements, aerospace components, defense instruments, manufacturing elements, bio-medical appliances, etc. In spite of their exceptional properties, the effective processing of these alloys is always seen as a challenge by researchers around the globe. The present article has been therefore attempted to explore the numerous studies conducted to process these alloys by employing the principles of electrical discharge machining (EDM) and its allied approaches. The NiTi-based SMAs have been revealed to be explored majorly among the several types SMAs. The several investigations carried out in the domain of EDM, Wire-EDM, and some conventional processing of various types of SMAs have also been critically reviewed and reported. It also highlights the numerous experimental, theoretical, modeling, and optimization-based researches attempted in EDM of SMAs. It was also reported that the proper selection of process variables, tool electrode, and the dielectrics can substantially improve the overall process effectiveness. Among the various accessible EDM variants used for the processing of SMAs, attempted by the umpteen investigators, the wire-cut EDM process has been revealed as the most explored one for cutting SMAs than the other allied processes such as: die-sinking EDM and powder-mixed EDM. The micro-machining applications of EDM have also been deliberated briefly. The last section of the article reports about the opportunities and the challenges for future research.


2020 ◽  
Vol 996 ◽  
pp. 131-136
Author(s):  
Yao Li ◽  
Cheng Cui ◽  
Bengang Lin ◽  
Li Li

Inconel718 has been widely used in various fields for its good performance, but it is difficult to machine with traditional machining methods. Electrical discharge machining is an alternative competitive process to machine Nickel-based alloys by electrical erosion. In order to improve reduce the electrode loss and improve the machining efficiency, the horizontal ultrasonic vibration of the workpiece and the cryogenic cooling of the tool electrode were applied into the EDM process. Material removal efficiency, surface roughness, surface topography, and microhardness have been characterized.


2012 ◽  
Vol 522 ◽  
pp. 17-20
Author(s):  
Wei Min Pan ◽  
Ke Ke Shi ◽  
Xian Qing Lei

Electrical discharge machining (EDM) processing is generally applied on the area of molding plastic component or mating surface required high accuracy. The areas determine the quality of the plastic components. The principle of EDM is based on the material vaporization of high potential difference across the workpiece and Tool electrode. Tool electrode and workpieces are discontiguous when the EDM processes. Because there is no mechanical contact, Hardness and strength of the workpiece material have minimal effect on the material removal rate .The application of EDM technology on injection mold of automotive connector is focused on in this paper. Processing of the complex cores is researched. The design and processing of the tool electrode have been completed in the meantime.


2010 ◽  
Vol 447-448 ◽  
pp. 238-241 ◽  
Author(s):  
Hiromitsu Ueno ◽  
Yuki Kono ◽  
Kai Egashira

The wire electrodischarge grinding (WEDG), which is one of the electrical discharge machining (EDM) methods, of submicron-diameter zinc micropins was attempted using a relaxation-type pulse generator. Tungsten wire of 30 µm diameter was employed as the tool electrode. The open-circuit voltage was set at lower than or equal to 15 V in the finish machining step. The electrostatic capacitance of the pulse generator was its stray capacitance only. As a result, a micropin of 0.3 µm diameter was processed. They are the smallest-diameter micropins fabricated by EDM, to the best of our knowledge.


2014 ◽  
Vol 611-612 ◽  
pp. 650-655 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Hans Peter Schulze ◽  
Oana Dodun ◽  
Irina Besliu ◽  
...  

Electrical discharge machining uses the pulse electrical discharges generated between the closest asperities existing on the workpiece surface and the active surface of the tool electrode in dielectric fluid. Essentially, some distinct electrical discharge machining schemas could be used in order to obtain cylindrical external surfaces; within this research, one preferred a machining schema based on the use of a cooper plate in which there were small diameter holes, by taking into consideration the existence of a ram electrical discharge machine. The results of the machining process analysis were presented. A thin copper was considered to be used as tool electrode, in order to diminish the spurious electrical discharges, able to generate shape errors of the machined surface. Some experimental researches were developed by changing the sizes of the process input parameters. As output factors, the test piece and tool electrode masses decreases were considered. Power type empirical mathematical models were determined, in order to highlight the influence exerted by the pulse on time, off time and machining process duration on the output parameters values.


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