Table 4.
Overview of published studies which considered the correlation of inclusion characteristics in different steel grades and their machinability parameters.
| Ref. | Year | Steel Grade a | Inclusion Characteristics | Machinability Parameter b | Main Result |
|---|---|---|---|---|---|
| [25] | 1995 | “Clean”, carbon | (Mn,Ca)S, elongated, (CaO-Al2O3), globular | TL | Ca-treatment improves machinability |
| [26] | 1995 | “Clean”, carbon, M-steel | (Mn,Ca)S, elongated, (CaOAl2O3), globular | TL, TW | Ca-treatment improves machinability |
| [27] | 1981 | Ca-treated, carbon, M-steel | CaO-Al2O3, globular, CaO-Al2O3-SiO2, anorthite, globular | TL, TW | Ca-treatment improves machinability |
| [5] | 2007 | Ca-treated, medium carbon steel, 0.35%–0.40% C, 0.02%–0.04% S | Al2O3-MgO, regular, CaO-Al2O3, 12CaO-7Al2O3, globular | TW | Ca-treatment improves machinability |
| [28] | 1993 | SS 2541, Q & T | MnS, elongated, (Mn,Ca)S, globular, (CaO-Al2O3)-(Mn,Ca)S and CaO-Al2O3-SiO2, globular | TL, TW | Decreased flank wear progression due to Ca-treatment |
| [29] | 2013 | 42CrMo, Q&T, 0.42% C, 0.0067% S | BN, globular, 5–20 µm | TW, CC | BN improved the machinability (drilling) |
| [30] | 1999 | AISI 4140, Q&T, 0.0017%–0.0030% Ca, 0.4% C | MnS, (Ca,Mn)S, globular | TL, CF | Reduced torque and adhesion due to Ca-treatment |
| [1] | 1993 | SS2541, ~0.35% C, 0.035% S 825B BB, 1% C, 0.011% S | MnS, (Ca,Mn)S, (CaO-Al2O3)-MnS, AlCaMnS | TW, CF | The protective (Mn,Ca)S layer reduced the crater wear |
| [31] | 1984 | SS 2506, CH, S, Ca ~0.2% C, 0.04%–0.09% S, 0.0003%–0.0054% Ca | MnS, elongated, (Mn,Ca)S~elongated, (CaO-Al2O3)-(Mn,Ca)S and (CaO-Al2O3-SiO2)-(Mn,Ca)S, globular | TL, TW | S and Ca-treatment improves machinability |
| [32] | 1986 | SS 2506, CH, Ca additions 0.04%–0.09% S | MnS, elongated, (Ca,Mn)S, (CaO-Al2O3)-(Mn,Ca)S, globular | TL, TW | Ca-treatment improves machinability |
| [33] | 2001 | 40 CrMnMo8 Carbon 0.4% C, 0.008%–0.067% S | MnS, elongated, 20–100 µm, oxides, globular, 10 µm | TL, TW, CC | S addition increased the machinability by 40% |
| [34] | 2001 | AISI 4340 ~0.4% C, 0.012%–0.034% S, 0–50 ppm O, 0–25 ppm Ca | (CaO-Al2O3)-(Mn,Ca)S, globular, 2–10 µm | TW, CF, CC | Ca-treatment indicates ridge formation after hard part turning |
| [35] | 1984 | Structural steel | S, Se, Pb, Ca | TL | Additions of S, Se, Pb, Ca improved the machinability |
| [36] | 1975 | Free mach, 0.3% S | MnS, elongated | TL, TW, CF | S additions improved the machinability |
| [37] | 1975 | Free mach., 0.1% S | MnS, elongated, Al2O3, globular | TL, TW | S additions improve machinability |
| [38] | 2006 | Free mach., 0.6% C, 0.3% S | MnS, elongated, 5–40 µm MnFe(Al,Si)S | CF, CC, SR | Cold deformation may improve machinability |
| [39] | 2012 | Free mach., ~0.08% C, ~0.4% S | MnS, elongated, 10–20 µm (MnO-Al2O3)-MnS, globular, 15 µm (MnO-SiO2)-MnS, elongated, 20 µm | TW, CC, SR | Increased oxygen content improved the machinability |
| [40] | 1997 | Free mach., 0.4% C, 0.1% S | (Mn,Ca)S, MnS, elongated, <10 µm, (RE,Ca)2S3-(Mn,Ca)S, Re2S3-MnS, globular, <10 µm | TW | Ca and RE additions increased the machinability of free-cutting steels |
| [41] | 1996 | Free mach., stainless steel, 0.04%–0.08% C, <0.1% S, <0.01% Ca | CaO-Al2O3-SiO2-MnS, MnS, Gehlenite, Anorthite | TL, TW, CF | Ca and S additions increased the machinability of stainless steel |
| [42] | 1990 | Stainless steel, 316 L 0.020%–0.027% C, 0.022%–0.025% S. 0.0002%–0.0045% Ca | MnS, (Mn,Ca)S, Gehlenite: Ca2Al[AlSiO7] + MnS Anorthite + MnS, elongated phases | TW, CF, CC | Anorthite inclusions are favorable for machining of 316L stainless steel |
| [3] | 2010 | Super-duplex stainless steel, 0.017%–0.021% C, 0.005%–0.034% S. REM additions | REM-O, Oxy-sulfides, (Mn,Cr)S, globular, 2–10 µm | TL, TW | S and REM additions increased the tool life but the corrosion resistance was decreased |
| [43] | 2011 | Austenitic stainess steel, 0.10%–0.11% C, 0.02%–0.11% S. Cu, Bi, Ti additions | MnS, Ti4C2S2, CuO, Bi, globular | TW, CF, CC | S, Bi, Cu and Ti additives improved the machinability |
Notes: a: steel grades: M-steel: Machinability improved steel; Q & T: Quench and tempered; CH: Case hardened steel; BB: Ball-bearing steel; b: machinability parameters such as the tool life (TL), tool wear (TW), cutting forces (CF), chip characteristics (CC), and surface roughness of work piece after machining (SR).