Please wait a minute...

Frontiers of Mechanical Engineering

Front. Mech. Eng.    2018, Vol. 13 Issue (2) : 243-250
Experimental study of surface integrity and fatigue life in the face milling of Inconel 718
Xiangyu WANG1,2, Chuanzhen HUANG1,2(), Bin ZOU1,2, Guoliang LIU1,2, Hongtao ZHU1,2, Jun WANG1,2,3
1. Centre for Advanced Jet Engineering Technologies (CaJET), School of Mechanical Engineering, Shandong University, Jinan 250061, China
2. Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Shandong University), Ministry of Education, Jinan 250061, China
3. School of Mechanical and Manufacturing Engineering, UNSW Australia, Sydney, NSW 2052, Australia
Download: PDF(485 KB)   HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

The Inconel 718 alloy is widely used in the aerospace and power industries. The machining-induced surface integrity and fatigue life of this material are important factors for consideration due to high reliability and safety requirements. In this work, the milling of Inconel 718 was conducted at different cutting speeds and feed rates. Surface integrity and fatigue life were measured directly. The effects of cutting speed and feed rate on surface integrity and their further influences on fatigue life were analyzed. Within the chosen parameter range, the cutting speed barely affected the surface roughness, whereas the feed rate increased the surface roughness through the ideal residual height. The surface hardness increased as the cutting speed and feed rate increased. Tensile residual stress was observed on the machined surface, which showed improvement with the increasing feed rate. The cutting speed was not an influencing factor on fatigue life, but the feed rate affected fatigue life through the surface roughness. The high surface roughness resulting from the high feed rate could result in a high stress concentration factor and lead to a low fatigue life.

Keywords roughness      hardness      residual stress      microstructure      fatigue life     
Corresponding Author(s): Chuanzhen HUANG   
Just Accepted Date: 24 November 2017   Online First Date: 29 December 2017    Issue Date: 16 March 2018
 Cite this article:   
Xiangyu WANG,Chuanzhen HUANG,Bin ZOU, et al. Experimental study of surface integrity and fatigue life in the face milling of Inconel 718[J]. Front. Mech. Eng., 2018, 13(2): 243-250.
Material grades Yield strength
Tensile strength
Elongation/% Hardness/HRC Average grain size (grade)
Inconel 718 1093 1295 14 42 8
Tab.1  Mechanical properties of the workpiece
No. v/(m•min–1) fz/(mm•tooth–1) ap/mm ae/mm
1 30 0.10 0.3 55
2 45 0.10 0.3 55
3 60 0.10 0.3 55
4 75 0.10 0.3 55
5 90 0.10 0.3 55
6 45 0.15 0.3 55
7 45 0.20 0.3 55
8 45 0.25 0.3 55
Tab.2  Cutting parameters for the face milling experiments
Fig.1  Schematic diagram of the three-point bending fatigue life test
Fig.2  3D morphologies and surface roughness profiles of the workpiece surface when machined at different cutting speeds. The unit of the values is μm. (a) v=45 m/min, fz=0.1 mm/tooth; (b) v=90 m/min, fz=0.1 mm/tooth
v/(m•min?1) Rp/mm Rv/mm Rz/mm Ra/mm Rc/mm Rsk Rku
30 0.74 0.72 1.46 0.19 0.97 0.05 2.84
45 0.63 0.58 1.32 0.16 0.85 0.08 2.69
60 0.49 0.63 1.11 0.16 0.83 −0.07 2.71
75 0.60 0.65 1.25 0.16 0.93 −0.34 2.94
90 0.58 0.80 1.38 0.17 0.97 −0.44 3.47
Tab.3  Surface roughness at different cutting speeds
fz/(mm•tooth?1) Rp/mm Rv/mm Rz/mm Ra/mm Rc/mm Rsk Rku
0.1 0.63 0.58 1.32 0.16 0.86 0.08 2.69
0.15 0.85 0.85 1.69 0.28 1.35 0.00 2.22
0.2 0.97 1.09 2.06 0.40 1.70 −0.17 1.98
0.25 1.19 1.31 2.50 0.51 2.02 −0.11 2.05
Tab.4  Surface roughness at different feed rates
Fig.3  Surface hardness of workpiece when machined at different cutting parameters
Fig.4  Cross-section microstructures at different cutting speeds. (a) 30 m/min; (b) 60 m/min; (c) 90 m/min (no white layer); (d) 90 m/min (with white layer)
Fig.5  Cross-section microstructures at different feed rates. (a) 0.1 mm/tooth; (b) 0.2 mm/tooth
Fig.6  Surface residual stress at different cutting speeds (fz=0.1 mm/tooth)
Fig.7  Surface residual stress at different feed rates (v=45 m/min)
Fig.8  Macro morphology of the fracture after fatigue life experiment
Fig.9  Micromorphologies of the fractures after the fatigue life experiment. (a) Crack initiation zone; (b) slow crack propagation zone
Fig.10  Fatigue life of the workpiece machined at different cutting speeds
Fig.11  Fatigue life of the workpiece machined at different feed rates
1 Dudzinski D, Devillez A, Moufki A, et al.. A review of developments towards dry and high speed machining of Inconel 718 alloy. International Journal of Machine Tools and Manufacture, 2004, 44(4): 439–456
2 Novovic D, Dewes R C, Aspinwall D K, et al.. The effect of machined topography and integrity on fatigue life. International Journal of Machine Tools and Manufacture, 2004, 44(2‒3): 125–134
3 Reed E C, Viens J A. The influence of surface residual stress on fatigue limit of titanium. Journal of Engineering for Industry, 1960, 82(1): 76–78
4 Darwish S M. The impact of the tool material and the cutting parameters on surface roughness of supermet 718 nickel superalloy. Journal of Materials Processing Technology, 2000, 97(1-3): 10–18
5 Sharman A R C, Hughes J I, Ridgway K. An analysis of the residual stresses generated in Inconel 718TM when turning. Journal of Materials Processing Technology, 2006, 173(3): 359–367
6 Devillez A, Le Coz G, Dominiak S, et al.. Dry machining of Inconel 718, workpiece surface integrity. Journal of Materials Processing Technology, 2011, 211(10): 1590–1598
7 Pusavec F, Hamdi H, Kopac J, et al.. Surface integrity in cryogenic machining of nickel based alloy—Inconel 718. Journal of Materials Processing Technology, 2011, 211(4): 773–783
8 Guo Y B, Li W, Jawahir I S. Surface integrity characterization and prediction in machining of hardened and difficult-to-machine alloys: A state-of-art research review and analysis. Machining Science and Technology, 2009, 13(4): 437–470
9 Ulutan D, Ozel T. Machining induced surface integrity in titanium and nickel alloys: A review. International Journal of Machine Tools and Manufacture, 2011, 51(3): 250–280
10 Hashimoto F, Guo Y B, Warren A W. Surface integrity difference between hard turned and ground surfaces and its impact on fatigue life. CIRP Annals-Manufacturing Technology, 2006, 55(1): 81–84
11 Warren A W, Guo Y B. The impact of surface integrity by hard turning vs. grinding on rolling contact fatigue. In: Proceedings of ASME 2007 International Manufacturing Science and Engineering Conference. Atlanta: ASME, 2007, 473–481
12 Guo Y B, Warren A W. The impact of surface integrity by hard turning vs. grinding on fatigue damage mechanisms in rolling contact. Surface and Coatings Technology, 2008, 203(3‒4): 291–299
13 Smith S, Melkote S N, Lara-Curzio E, et al.. Effect of surface integrity of hard turned AISI 52100 steel on fatigue performance. Materials Science and Engineering A, 2007, 459(1‒2): 337–346
14 Matsumoto Y, Magda D, Hoeppner D W, et al.. Effect of machining processes on the fatigue strength of hardened AISI 4340 Steel. Journal of Manufacturing Science and Engineering, 1991, 113: 154–159
15 Jeelani S, Musial M. Effect of cutting speed and tool rake angle on the fatigue life of 2024-T351 aluminium alloy. International Journal of Fatigue, 1984, 6(3): 169–172
16 Javidi A, Rieger U, Eichlseder W. The effect of machining on the surface integrity and fatigue life. International Journal of Fatigue, 2008, 30(10‒11): 2050–2055
17 Sasahara H. The effect on fatigue life of residual stress and surface hardness resulting from different cutting conditions of 0.45%C steel. International Journal of Machine Tools and Manufacture, 2005, 45(2): 131–136
18 Wang X, Huang C, Zou B, et al.. Tool life of coated tools in face milling of GH4169 at various cutting speeds. Materials Science Forum, 2013, 770: 126–129
19 Wang X, Huang C, Zou B, et al.. A new method to evaluate the machinability of difficult-to-cut materials. International Journal of Advanced Manufacturing Technology, 2014, 75(1‒4): 91–96 doi:10.1007/s00170-014-6126-7
20 Zheng X. A further study on fatigue crack initiation life—Mechanical model for fatigue crack initiation. International Journal of Fatigue, 1986, 8(1): 17–21
Related articles from Frontiers Journals
[1] Xinyu HUI, Yingjie XU, Weihong ZHANG. Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer composites[J]. Front. Mech. Eng., 2020, 15(3): 475-483.
[2] Arun KRISHNAN, Fengzhou FANG. Review on mechanism and process of surface polishing using lasers[J]. Front. Mech. Eng., 2019, 14(3): 299-319.
[3] Jiadong DENG, Claus B. W. PEDERSEN, Wei CHEN. Connected morphable components-based multiscale topology optimization[J]. Front. Mech. Eng., 2019, 14(2): 129-140.
[4] B. J. WANG, D. K. XU, S. D. WANG, E. H. HAN. Fatigue crack initiation of magnesium alloys under elastic stress amplitudes: A review[J]. Front. Mech. Eng., 2019, 14(1): 113-127.
[5] Jinya KATSUYAMA, Shumpei UNO, Tadashi WATANABE, Yinsheng LI. Influence evaluation of loading conditions during pressurized thermal shock transients based on thermal-hydraulics and structural analyses[J]. Front. Mech. Eng., 2018, 13(4): 563-570.
[6] Edward WANG, Zihui XIA. Optimal slot dimension for skirt support structure of coke drums[J]. Front. Mech. Eng., 2018, 13(4): 554-562.
[7] Tianfeng ZHOU,Xiaohua LIU,Zhiqiang LIANG,Yang LIU,Jiaqing XIE,Xibin WANG. Recent advancements in optical microstructure fabrication through glass molding process[J]. Front. Mech. Eng., 2017, 12(1): 46-65.
[8] Lei XU,Huajun CAO,Hailong LIU,Yubo ZHANG. Assessment of fatigue life of remanufactured impeller based on FEA[J]. Front. Mech. Eng., 2016, 11(3): 219-226.
[9] Bo SONG,Xiao ZHAO,Shuai LI,Changjun HAN,Qingsong WEI,Shifeng WEN,Jie LIU,Yusheng SHI. Differences in microstructure and properties between selective laser melting and traditional manufacturing for fabrication of metal parts: A review[J]. Front. Mech. Eng., 2015, 10(2): 111-125.
[10] Zhaoxu QI,Bin LI,Liangshan XIONG. The formation mechanism and the influence factor of residual stress in machining[J]. Front. Mech. Eng., 2014, 9(3): 265-269.
[11] Zhaoxu QI,Bin LI,Liangshan XIONG. Improved analytical model for residual stress prediction in orthogonal cutting[J]. Front. Mech. Eng., 2014, 9(3): 249-256.
[12] Zhaoxu QI,Bin LI,Liangshan XIONG. An improved algorithm for McDowell’s analytical model of residual stress[J]. Front. Mech. Eng., 2014, 9(2): 150-155.
[13] Rupesh CHALISGAONKAR, Jatinder KUMAR. Optimization of WEDM process of pure titanium with multiple performance characteristics using Taguchi’s DOE approach and utility concept[J]. Front Mech Eng, 2013, 8(2): 201-214.
[14] Guanglan LIAO, Haibo ZUO, Xuan JIANG, Xuefeng YANG, Tielin SHI. Investigations on color variations of Morpho rhetenor butterfly wing scales[J]. Front Mech Eng, 2012, 7(4): 394-400.
[15] Kirsten BOBZIN, Lidong ZHAO, Nils KOPP, Thomas WARDA. Feasibility study of plasma sprayed Al2O3 coatings as diffusion barrier on CFC components[J]. Front Mech Eng, 2012, 7(4): 371-375.
Full text



  Shared   0