Issue 68

P. Kulkarni et alii, Frattura ed Integrità Strutturale, 68 (2024) 222-241; DOI: 10.3221/IGF-ESIS.68.15

R ESULTS AND DISCUSSION

I

n this study, the turning performance of Inconel 718 was assessed considering three components of cutting force, namely the tangential cutting force ( F c ), feed force ( F f ), and radial force ( F r ), machined surface roughness ( R a ), and tool life ( T ) , through mathematical modeling and a multi-objective optimization approach. In addition, the effects of unitary Al 2 O 3 and hybrid Al 2 O 3 +MWCNT nanofluids on chip morphology and tool wear mechanisms under MQL circumstances were analyzed. Turning experiments were conducted under NFMQL conditions, and experimental results for unitary and hybrid nanofluids are depicted in Tab. 4.

Hybrid Al 2 O 3 +MWCNT nanofluid

Unitary Al 2 O 3 nanofluid

Expt. Index

Cutting speed ( V ) (m/min)

Depth of cut ( d ) mm)

Feed ( f ) (mm/rev)

F f (N)

F f (N)

F c (N)

F r (N)

R a (µm) 1.73 1.77 1.23 1.82 1.53 1.06 1.81

T (min)

F c (N)

F r (N)

R a (µm)

T (min)

1 2 3 4 5 6 7 8 9

65 45 45 85 85 65 65 65 30 45 45 85 85 65

0.2

0.8 0.7 0.7 0.7 0.7 0.5 0.5 0.5 0.5 0.5 0.3 0.3 0.3 0.3 0.2

558 277 84 388 226 64

2.48 537 245 77 1.49 5.88 431 198 68 1.36 3.55 617 338 108 1.9 2.06 374 156 48 1.15 1.24 568 265 76 1.78 2.80 277 142 47 1.42

4.21 7.70 5.46 3.01 2.14 4.06 7.18 3.29

0.15 0.25 0.15 0.25

627 316 109 2.24

382 167 56 607 287 95 369 139 65 509 258 75 431 164 63 342 128 36 176 79 36

0.2 0.1 0.3 0.2 0.2

5.67 168 86

33 0.93

2.14 473 255 71 1.88

2.16 11.03 343 156 56 2.06 14.14

10 11 12 13 14 15

100

1.39

1.35 313 116 38 1.15

2.08

0.15 0.25 0.15 0.25

195 69

29

1.19 10.91 166 67

31 1.02 12.91

264 118 46

1.53 0.73 1.37 1.32

6.58 248 96 3.81 136 57 2.30 234 87 6.06 107 57

34 1.82 26 0.94 34 1.32 24 1.02

9.15 5.05 3.58 8.09

146 69 264 95 117 59

22 29 17

0.2

Table 4: Experimental design and results.

Mathematical models Mathematical models are developed to understand the parametric effect on machining performance with unitary and hybrid nanofluids. Regression equations were developed based on experimental data. The unknown coefficients in the equation were calculated using the DataFit software. Eqns. (11)-(20) presents empirical models for predicting responses during the turning of Inconel 718 alloy under NFMQL conditions. These models can be used to optimize the turning process and improve machining performance.



0.1342 0.9109 0.9903



c F

V f

d

5390.305

(11)

V f 

0.197 0.9983 1.2382



(12)

f F

d

4230.465



0.2961 0.9056 1.104303



r F

V f

d

1706.818

(13)



0.4087 0.5516 0.3528



a R

V f

d

25.9848

(14)

1.652 0.99 0.7292   

373.0818 T V f 

d

(15)

228