Machinability Studies in Drilling of Inconel 718 Super Alloy

Abstract:

Inconel 718, a Nickel based superalloy is widely used for aerospace applications mainly due to its high temperature resistance and high strength to weight ratio. Its poor machinability is a limiting factor in commercial, cost intensive applications. This paper investigates the machinability of Inconel 718 in high speed drilling. The impact of the material on thrust forces, torque and chip microstructure have been measured at four different cutting speeds – 19, 27,43 and 67 m/min. The high tensile strength coupled with low thermal conductivity compounds the machining process. The thrust forces decrease with cutting speed, but the torque fluctuates at intermediate cutting speeds. Chip formation is continuous across cutting speeds, with thin cross sections and evidence of saw tooth edges. Inconel work hardens more than titanium alloys and shows good ductile to brittle transition at low temperatures creating chips of lesser length as observed using scanning electron microscopy.

• Periodical: Applied Mechanics and Materials (Volume 787)
• Pages: 480-484
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.787.480
• Online since: August 2015
• Authors: M. Vimalesh*, Srikanth Prabhu, K.S. Vijay Sekar
• Keywords: Chip Morphology, Cutting Force, Drilling, Inconel 718, Super Alloy, Torque

References

[1] D. Umbrello, Investigation of surface integrity in dry machining of Inconel 718, International Journal of Advanced Manufacturing Technology, 69 (2013) 2183-2190.

DOI: 10.1007/s00170-013-5198-0

[2] K. Zhuang, Dahu Zhu, Xiaoming Zhang and Han Ding, Notch wear prediction model in turning of Inconel 718 with ceramic tools considering the influence of work hardened layer, Wear, 313 (2014) 63-74.

DOI: 10.1016/j.wear.2014.02.007

[3] P.J. Arrazola, A. Kortabarria, A. Madariaga, J.A. Esnaola, E. Fernandez, C. Cappellini, D. Ulutan, T. Ozel, On the machining induced residual stresses in IN718 nickel based alloy: Experiments and predictions with finite element simulation, Simulation Modelling Practice and Theory, 41 (2014).

DOI: 10.1016/j.simpat.2013.11.009

[4] S. Olovsjo, A. Wretland, G. Sjoberg, The effect of grain size and hardness of wrought alloy 718 on the wear of cemented carbide tools, Wear, 268 (2010) 1045-1052.

DOI: 10.1016/j.wear.2010.01.017

[5] Y.C. Chen, Y.S. Liao, Study on wear mechanisms in drilling of Inconel 718 superalloy, Journal of Materials Processing Technology, 140 (2003) 269-273.

DOI: 10.1016/s0924-0136(03)00792-1