Surface Integrity of Inconel 718 by Wire-EDM at Different Energy Modes

Li, L.; Wei, Xiuting; Guo, Y. B.; Li, W.; Liu, J. F.

doi:10.1007/s11665-014-1048-y

Cited by 21 publications

(12 citation statements)

References 19 publications

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“…The increased hardness of white layers was attributed to the formation of oxides and/or carbides. However, Li et al [3] and Qu et al [14] found the hardness of white layers were not higher than the bulk in EDM of Inconel 718 and WC-Co composites, respectively. Therefore, the hardness of white layer in EDM is material dependent.…”

Section: Introductionmentioning

confidence: 95%

“…Kruth et al [6] detected saturated carbon in the white layer by XRD, which was diffused from the CH-oil dielectric when EDM of mold steel Impax. Hsieh et al [10] and Li et al [3] detected diffused oxygen in the white layer of wire-EDMed Ti 35.5 Ni 49.5 Zr 15 and IN 718 in the water dielectric. Klocke et al [12] observed that the white layer contained foreign elements (O, Cu, and Zn) from the water dielectric and brass electrode in wire-EDMed WE43 magnesium alloys at the main cut mode, while foreign elements (O, Cu, and Zn) were barely observed in the white layer at the finish trim cut mode.…”

Section: Introductionmentioning

confidence: 99%

“…In EDM processes, the main cut mode uses high discharge energy for rough cutting to increase material removal rate, while the trim cut mode uses low discharge energy for finish cutting to improve surface integrity. Klink et al [2] and Li et al [3] discovered that the white layers at the main cut mode exhibited a discontinuous and non-uniform microstructure when wire-EDM of ASP 23 tool steel and IN 718 alloys, and WLs were continuous and uniform at the finish trim cut mode. Liu et al [4] showed that the WL thickness in wire-EDM of Nitinol SMAs can be significantly reduced at the finish trim cut mode.…”

Section: Introductionmentioning

confidence: 99%

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Crystallography, compositions, and properties of white layer by wire electrical discharge machining of nitinol shape memory alloy

et al. 2016

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Nitinol shape memory alloy (SMA) is very challenging to machine by conventional mechanical cutting. Wire electric discharge machining (wire-EDM) is an alternative process to machine Nitinol SMAs. The machined surface integrity is critical to product performance such as fatigue, corrosion, and wear, yet few studies have conducted a thorough investigation of the machined surface integrity, in particular white layer (WL). This work focuses on a comprehensive investigation on the crystallography, compositions, and properties of the white layer using transmission electron microscopy (TEM), X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and nanoindentation. The WL by wire-EDM exhibits a porous and nonuniform bi-layered structure. The white layer of Nitinol by EDM is a crystalline structure instead of the traditionally believed amorphous solid. The upper portion of the WL consists of primarily the solid solution phase (Cu+Ni+Zn)-FCC, while Ti 2 O 3 and Nitinol austenite phases dominate the lower portion of the WL. The white layer shows less crystal plastic deformation than the bulk material, and refined grains with random orientation can be found in the WL. The nanohardness of the WL is much higher than that of the bulk material due to oxide hardening.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crystallography, compositions, and properties of white layer by wire electrical discharge machining of nitinol shape memory alloy

et al. 2016

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“…A discharge current of 4 A and 20 μs of pulse duration provides the best practical results of Ra [72]. Studies analyzed the effects of different modes of electrical discharges in the process of wire and sinking ED-machining, and an example is the work of Li et al [88], where the surface roughness was reduced from 3.75 to 1.25 μm with low energy discharge values. Finally, considering the variation of the holes due to the intensity of the electrical discharges, Atzeni et al [87] identified a variation in diameter with a conical shape along with the depth, and adherence of debris, which in this case, was caused by the secondary electric discharges.…”

Section: Electrode Type and Surface Integritymentioning

confidence: 99%

Machining of Inconel 718 with a defined geometry tool or by electrical discharge machining

Baldin

Machado

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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Inconel 718 alloy is the most used nickel-based superalloy owing to its characteristics of excellent mechanical and chemical properties at high temperatures and relatively low cost in comparison with other alloys. Nevertheless, the mechanical properties and components with intricate geometric shapes usually lead to difficulty in machining this alloy. This article reports a literature review on the machining performance of Inconel 718 alloy using conventional machining processes as well as electrical discharge machining. Based on the literature review, it is possible to highlight that for conventional machining, non-uniform flank wear and notch at the depth of cut are the leading causes for cutting tool failure when machining Inconel 718. Abrasion is the prominent wear mechanism, followed by diffusion, adhesion, and chipping. Regarding the assessed literature, 65% used cemented carbide as cutting tool material, 20% used ceramic cutting tools, and 15% applied CBN tools. For ED-machining, copper is the most used material as a tool electrode, followed by brass and graphite. Regarding the electrical variables, discharge currents applied are from 10 to 20 A, and the pulse duration varies from 50 to 200 µs. The thickness of the white layer, varying from 3 to 50 μm, depends directly on the combination of process parameters, which involves the variation of discharge current and pulse duration.

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“…However, phenomenon involved in EDM process and achieved surface integrity have been traditionally challenged and researchers still debate on some aspects [13]. The surface alterations generated by EDM process have an important in uence on surface integrity as stated in several studies [12][13][14][15]. Hence the importance of optimizing the whole of the factors involved in EDM process namely, the type of EDM process (WEDM or SEDM), the job and electrode tool materials, the machinery parameters, the characteristics of the employed dielectric liquid along with material removal rate MRR, kerf size, wire failure and wire wear rate frequency, cutting rate etc.…”

Section: Introductionmentioning

confidence: 99%

An Investigation To Achieve a Good Surface Integrity in WEDM of Ti-6242 Super Alloy

Ezeddini

Rajhi

Boujelbene

et al. 2021

Preprint

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Ti-6242 is a super alloy which exhibits the best creep resistance among available titanium alloys and is widely used in the manufacture by WEDM of aircraft engine turbomachinery components. However, the final quality of wire EDMed surface is a great challenge as it is affected by various factors that need optimization for surface integrity and machine efficiency improvement. The aim of this study is to investigate the effect of a set of cutting process parameters such as pulse on time (Ton), servo voltage (U), feed rate (S) and flushing pressure (p) on surface roughness (SR) when machining Ti-6242 super alloy by WEDM process using a brass tool electrode and deionized water as a dielectric fluid. WEDM experiments were conducted, and SR (Ra) measurement was carried out using a 3D optical surface roughness-meter (3D–SurfaScan). As a tool to optimize cutting parameters for SR improvement, Taguchi's signal‐to‐noise ratio (S/N) approach was applied using L9 (3^4) orthogonal array and Lower-The-Better (LTB) criteria. Substantially, the findings from current investigation suggest the application of the values 0.9 µs, 100V, 29 mm/min, and 60 bar for Ton, U, S and p cutting parameters, respectively, for producing a good surface finish quality. Percent contributions of the machining parameters on SR (Ra) assessed based on ANOVA analysis are 62.94%, 20.84%, 11.46% and 4.74% for U, S, Ton and p, respectively. Subsequently, accurate predictive model for SR (Ra) is established based on response surface analysis (RSA). The contour plots for SR (Ra) indicate that when flushing pressure p converges to a critical value (80 bar), a poor-quality surface finish is highly expected with the excessive increase in U and S. Electron microscope scanning (SEM) observations have been performed on machined surface for a wide range of cutting parameters to characterize wire EDMed surface of Ti-6242. SEM micrographs indicate that the machined surface acquires a foamy structure and shows white layer and machining-induced damage that the characteristics are highly dependent on cutting parameters. At high servo-voltage, the decrease in pulse on time Ton and feed rate S results in a large decrease in overall machining-induced surface damage. Moreover, for high servo-voltage and feed rate levels, it has been observed that pulse on time could play a role of controlling the surface microcracks density. In fact, the use of a low pulse duration of cut combined with high servo-voltage and feed rate has been shown to inhibit surface microcracks formation giving the material surface a better resistance to cracking than at high pulse duration.

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Surface Integrity of Inconel 718 by Wire-EDM at Different Energy Modes

Cited by 21 publications

References 19 publications

Crystallography, compositions, and properties of white layer by wire electrical discharge machining of nitinol shape memory alloy

Crystallography, compositions, and properties of white layer by wire electrical discharge machining of nitinol shape memory alloy

Machining of Inconel 718 with a defined geometry tool or by electrical discharge machining

An Investigation To Achieve a Good Surface Integrity in WEDM of Ti-6242 Super Alloy

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