Table 2.

Details of EDM process research studies for different grades of stainless steels.

Grades and Corresponding Machining Operations	Composition (wt.%)	Properties
AISI (SUS) 304 Die-sinking EDM [88,156,157,158,159,160,161,162,163,164,165] Wire EDM [166] Micro-EDM [167,168,169,170,171,172,173] Dry EDM [48,174,175,176,177] Powder-mixed EDM [88]	C ≤ 0.08, Cr 18.00–20.00, Mn ≤ 2.0, Ni 8–10.5, P ≤ 0.045, S ≤ 0.03, Si ≤ 1.00	Excellent corrosion resistance and very good drawability. It has low yield strength and high elongation. It can be welded by all fusion and resistance welding processes [178].
AISI 304 L Micro-EDM [179]	C ≤ 0.03, Cr 18.00–20.00 Mn ≤ 2. 00, Ni 10.00–13.00, P ≤ 0.045, S ≤ 0.030, Si ≤ 1.00,	The low carbon version of 304. It has good resistance to carbide precipitation and so is recommended for corrosion resistance in water [178].
AISI (SUS) 316 Die-sinking EDM [180] Wire EDM [181] Micro-EDM [182]	C ≤ 0.08, Cr 16.00–18.00, Mo 2.00–3.00, Mn ≤ 2.00, Ni 10.00–14.00, P ≤ 0.045, S ≤ 0.030, Si ≤ 1.00,	It has excellent corrosion resistance. Subject to pitting and crevice corrosion in warm chloride environments and to stress corrosion cracking above about 60 °C. It cannot be hardened by thermal treatment. It has excellent weldability by all fusion methods.
AISI 316L Die-sinking EDM [183,184,185,186] Micro-EDM [187]	C ≤ 0.03, Cr 16.00–18.00, Mn ≤ 2.00, Mo 2.00–3.00, Ni 12.00–15.00, P ≤ 0.045, S ≤ 0.030, Si ≤ 1.00,	The low carbon version of 316. It is more resistant to carbide precipitation and has higher strength at elevated temperatures.
AISI 202 Die-sinking EDM [56,188,189]	C ≤ 0.15, Cr 17.00–19.00, Mn 7.50–10.00, N ≤ 0.25, Ni 4.00–6.00, P ≤ 0.060, S ≤ 0.030, Si ≤ 0.75,	Excellent toughness at low temperatures. When machined produces long, gummy chips. The material can be welded by fusion and resistance methods but should not be joined using oxyacetylene welding. Forging below 1010 °C (1850 °F) is not advisable for this grade [190].
AISI 440 A2 Wire EDM [108,191]	C 0.39, Cr 15.89, Mo 1.02, Mn 0.87, P < 0.003, S < 0.003, Si 0.46,	This grade has high hardness, wear resistance and strength. It loses mechanical properties by over-tempering; therefore, it should not be used at temperatures below the relevant tempering temperature. It is fully annealed at 850 to 900 °C.
AISI 420 Wire EDM [192]	C 0.16–0.25, Cr 12.00–14.00 Mn ≤ 1.00, P ≤ 0.040, S ≤ 0.030, Si ≤ 1.00,	A high-carbon steel with minimum chromium content of 12%. It offers good ductility in its annealed state and excellent corrosion resistance properties when the metal is polished, surface ground or hardened. It has corrosion resistance.
Modified AISI 420 Wire EDM [193]	C 0.38, Cr 13.6, Mn 0.5, Si 0.9, V 0.3	Similar to grade 420 with more carbon content.
Ferralium 255 SD 50 (plate) Micro EDM [194]	C max 0.03, Cr 24.50–25.50, Cu 1.5–2.0, Mn 0.8–1.2, Mo 3.20–3.80, N 0.21–0.24, Ni 5.60–6.50, P ≤ 0.035, S ≤ 0.030, Si ≤ 0.4	Super duplex ferralium 255 SD50 has high yield strength, withstanding stresses of over 550 N/mm2. It has excellent corrosion resistance to corrosive. In seawater it offers superior resistance to crevice corrosion and pitting. It shows excellent ductility and impact resistance combined with a great resistance to abrasion, erosion and cavitation erosion.
19-5PH Die-sinking EDM [195]	C ≤ 0.07, Cr 14.00–15.50, Cu 2.50–4.50, Mn ≤ 1.00, P ≤ 0.040, Nb + Ta 0.15–0.45, Ni 3.50–5.50, S ≤ 0.030, Si ≤ 1.00,	Exhibits high strength and hardness with moderate corrosion resistance; has high toughness, especially in the through-thickness (short transverse) direction. Used in applications that require high transverse strength and toughness [196].
1Cr18Ni9Ti Micro EDM [197]	C max 0.12, Cr 17.0–19.0, Mn ≤ 2.00, Ni 8.0–11.0, P 0.035, S 0.030, Si ≤ 1.00, Ti 5 × (C% 0.02−0.80)	Has a good wear resistance [198].
Other grades Die-sinking EDM [199,200,201,202,203] Micro-EDM [41,204,205,206,207] Dry EDM [136] Wire EDM [208,209]	Grade not mentioned	Grade not mentioned