Study on Cutting Force and Tool Wear while Milling Ni3Al-

Based Superalloy

Liu Xianpeng1, Zhao Zhengcai1, Fu Yucan1, Su Honghua1, Liu

Gaoqun1,2

1College of Mechanical and Electrical Engineering, Nanjing University of

Aeronautics & Astronautics, 210016 China 2 AVIC Nanjing Engineering Institute of Aircraft System 210016 China

Keywords: Superalloy, NiAl base, Milling, Cutting force, Tool wear

Abstract: Ni3Al-based superalloy is a kind of typical hard-to-cut material due to its

low thermal conductivity and high strength at elevated temperatures, which lead to

dramatical tool wear in the milling progress. To understand the cutting force and the

tool wear behavior in milling process, the influence of cutting parameters on cutting

forces and tool wear in the milling of Ni3Al-based superalloy by using carbide coated

milling cutter is investigated in this paper. Through orthogonal experiment, a linear

regression is carried out with the results and an empirical formula for milling forces

applicable to the test condition is derived. The results show that the cutting forces

increase with the increase of cutting feed rate, radial depth and axial depth of cut.

Besides, the feed per tooth is the main factor affecting of cutting force, and axial depth

of cut has greatest influence on tool wear. The proposed research provides the basic

data for evaluating the machinability of milling Ni3Al-based superalloy and the

recommended cutting parameters can be applied in practical production.

Introduction Ni3Al-based superalloy has excellent oxidation and corrosion resistance, which can

maintain high strength at the temperature above 1000℃ [1]. It is very suitable for

manufacturing the blade disc [2-3]. However, the nickel-aluminum alloy generally has a

large coefficient of friction and a lower thermal conductivity, so it is easy to work

hardening in its processing. Work hardening will aggravate the wear of the machining

tool and the cutting temperature and force, thus limiting the widespread use of the

material [4].

Since the Ni3Al-based superalloy has good high temperature properties, many

researchers have studied its machining process, in order to overcome its processing

defects and expand its application area [5]. Pawade et al. [6] set the appropriate range of

cutting speed and depth of cut, in the conditions of feed rate of 0.15 mm/rev, by which

the effects of cutting parameters on cutting force size were concluded: with the increase

or decrease of cutting speed, cutting force appears to decrease or increase. This is

mainly attributed to such a fact that the heat in the shear zone cannot be quickly passed

out, thus the elevated temperature results in the workpiece plastic deformation, material

softening, thereby decreasing the cutting force. Erdogan et al. [7] found that there was a

positive relationship between the feed rate and the internal force of the cutting, which

became larger as the former increased. Liu et al. [8] gave the tool wear, cutting

386

Advances in Abrasive Technology XX

temperature and cutting force of the six alloys of GH80A, GH738, GH4169, GH4033,

GH3044, GH3030 and so on. Nalbant et al. [9] experimentally studied the impact of

cutting speed and tool geometry parameters on the machinability of nickel-based

superalloys, and drew the following conclusions: when the cutting speed increased by

66.6%, the cutting force reduced by 14.6%; when the feed rate increased by 20%, the

cutting force increased by 10.4%. Xin and Wang [10] described that cemented carbide

tool was used to cut nickel-based alloy in high speed. The result shows that at a small

feed (f = 0.09 mm/r) and a small cutting depth (ap =0.12mm), the cutting speed could

be up to vc = 120 m/min. Han [11] found that the abrasive resistance of cemented carbide

tool with coating was better than that of ultrafine grain and ordinary carbide ones, as

well as the abrasive wear was attributed to the main cause of the crater on rake face.

Despite lots of works have been performed on the machinability of nickel-based alloy,

most of them focused on the turning process. On the basis of the selected tool materials

and tool geometry, a reasonable selection of cutting parameters can achieve greater

efficiency, and optimize machining effects. To study the tool wear behavior in milling

process and reduce tool wear, the effects of cutting parameters on tool wear in the end

milling of Ni3Al-based superalloy with carbide coated milling cutter is studied.

Experimental Details

The material used in this research is Ni3Al-based superalloy. The chemical

components are listed in table 1. The physical properties of Ni3Al-based superalloy are

as follows:7.83g/cm3 (Density), 280MPa (Tensile strength, yield), 12.39/10-6/K

(Thermal expand coefficient), 9.64W/m-K (Thermal Conductivity), 29HRC (Hardness),

1302―1357℃ (Melting Point).

Table 1 Chemical composition of Ni3Al-based superalloy

C Cr Al Ti Hf W Ni

0.06-0.20 7.40-8.20 7.60-8.50 0.60-1.20 0.300-0.900 1.50-2.50 Balanced

The setup for milling experiment is shown in Fig. 1. The entire machining tests were

carried out on DMG ULTRASONIC 20 linear and the four-component dynamometer

（Kistler-9272B） was used to measure the cutting force. The cutting tools used in the

experiment were carbide coated milling cutters. The geometrical parameters of carbide

coated milling cutters used in the experiment were listed as follows. The cutter diameter

is 3mm, and the spiral angle is 42°.

Fig. 1 Experimental setup

Listed in Table 2 are the used cutting parameters. In order to measure the tool wear,

Cutting tool

Workpiece

Dynamometer

387

Proceedings of the 20th International Symposium on Advances in Abrasive Technology 3-6 December, Okinawa, Japan

three-dimension microscope was used to get the tool wear width. From the optical

measurement results, flank wear was observed as the main wear mechanism in the

milling test with carbide coated milling cutters.

Table 2 Cutting parameters used in the experiments

No. axial depth of

cut ap（mm）

radial depth of

cut ae（mm）

feed per tooth

fz（mm/z）

𝑭𝒙

（N）

𝑭𝒚

（N）

𝑭𝒛

（N）

01 0.2 1 0.004 37.64 11.05 53.81

02 0.4 1.5 0.006 76.53 14.50 102.5

03 0.6 3 0.008 118.0 82.32 168.9

04 0.2 1.5 0.008 57.18 15.48 93.80

05 0.4 3 0.004 60.79 50.46 125.1

06 0.6 1 0.006 96.28 21.54 99.43

07 0.2 3 0.006 52.0 50.50 135.8

08 0.4 1 0.008 86.69 9.83 104.2

09 0.6 1.5 0.004 119.4 10.26 118.6

Results and Discussions

Influence of cutting parameters on milling force

The empirical formula of milling force is established by means of multiple linear

regression analysis and Matlab software. The empirical formula of milling force in

exponential form is obtained

𝐹𝑥 = 957.86𝑎𝑝0.74𝑎𝑒

0.10𝑓𝑧0.36

𝐹𝑦 = 103.12𝑎𝑝0.19𝑎𝑒

2.02𝑓𝑧0.41 (1)

𝐹𝑧 = 700.01𝑎𝑝0.32𝑎𝑒

0.77𝑓𝑧0.36

The range analysis of carbide coated milling cutter is carried out in table 3. The main

factors affecting tangential force 𝐹𝑥 and axial force 𝐹𝑧 are ap, fz, ae. The main factors

affecting radial force 𝐹𝑦 are fz, ae, ap. In order to increase the metal removal rate, the

increase of axial cutting depth should not be taken as the first choice to increase the

feed per tooth and the radial depth.

Table 3 The results of range analysis on the cutting force

factors levels 𝑭𝒙 𝑭𝒚 𝑭𝒛

ap

A1 148.89 220.61 217.83

A2 224.01 255.11 224.88

A3 333.68 230.86 263.87

R 184.79 34.5 46.04

ae

B1 77.03 42.42 71.34

B2 74.79 40.24 86.54

B3 114.1 183.26 107.61

R 39.31 143.02 36.27

fz

C1 283.41 257.44 297.51

C2 331.8 314.9 337.73

C3 386.93 429.8 366.9

R 103.52 172.36 69.39

388

Advances in Abrasive Technology XX

In Fig.2 (a), (b) and (c), the variation curves of milling forces obtained under different

cutting parameters are shown. In general, the milling force increases with the axial

depth of cut, the radial depth of cut and the feed per tooth when using the SGS carbide

coated milling cutter, which is consistent with the energy consumption principle. These

machining parameters produce lower forces at low and medium levels respectively.

With the increase of the axial cutting depth, the three directions of milling force show

increasing trends. During the machining process, the interaction between the tool and

the workpiece causes the severe plastic deformation in the local area of workpiece, and

the intense friction at the tool-workpiece interface. The material being removed

influences the cutting forces. According to the milling area formula Ac = ap×f, the

increase of feed or axial cutting depth can lead to the increase of milling area. So the

friction between the tool rake face and the workpiece material increases, and the milling

force increases. When the axial depth of cut is less than 0.8mm, the cutting force is low

and the cutting performance is stable. The axial force 𝐹𝑧 increased along with the

increase of feed rate approximately linearly. 𝐹𝑦 and 𝐹𝑥 changed little with the

variation of the feed rate. When feed per tooth is less than 0.01mm/z, the cutting force

is low, the cutting performance is stable. When feed per tooth reaches 0.02mm/z, cutting

edge breaks.

0.2 0.4 0.6 0.8 1.0

50

100

150

200

250

300

Cu

ttin

g f

orc

e/N

Fx

Fy

Fz

Axial depth of cut/mm1.0 1.5 2.0 2.5 3.0

0

50

100

150

200

Cu

ttin

g f

orc

e/N

Radial depth of cut/mm

Fx

Fy

Fz

(a) Axial depth of cut (b) Radial depth of cut

0.002 0.004 0.006 0.008 0.010

40

60

80

100

120

140

160

180

200

220

Cu

ttin

g f

orc

e/N

Feed per tooth/mm/z

Fx

Fy

Fz

(c) Feed per tooth

Fig.2 Effects of cutting parameters on cutting force

Influence of feed per tooth on tool wear

Generally, the cutting time and material removal amount are chosen as the standard

to measure tool life before reaching wear standard. The amount of material removed is

389

Proceedings of the 20th International Symposium on Advances in Abrasive Technology 3-6 December, Okinawa, Japan

defined as follow.

V = 𝑎𝑝 ∙ 𝑎𝑒 ∙ 𝑙 = 𝑎𝑝 ∙ 𝑎𝑒 ∙ 𝑓𝑧 ∙ 𝑧 ∙ 𝑛 ∙ 𝑇 =1000∙𝑣∙𝑎𝑒∙𝑎𝑝∙𝑓𝑧∙𝑧∙𝑇

𝜋∙𝑑(mm3) (2)

The effects of feed per tooth on the tool wear are shown in Fig.3. Other cutting

parameters are v= 37.6 m/ min, ap = 0.4 mm, ae = 3.0 mm. The results show that tool

wear increases greatly with the increase of feed per tooth. When the material removal

exceeds 1560 mm3 under feed per tooth of 0.01 mm/z, rapid tool wear or fatigue tipping

of the cutting edge was observed. When feed per tooth is less than 0.01mm/z, tool wear

increases gradually with the increase of material removal. As feed per tooth increases,

the results show that tool wear rate continues to increase due to the increase of cutting

heat and force. Increase of cutting heat will lead to higher cutting temperature, which

will aggravate the failure of coating. Hence, tool wear rate will increase rapidly without

coating under high cutting temperature and large cutting force.

0.1

0.2

0.3

0.4

0.5

0.6

0 500 1000 1500 2000 2500 3000

Material removal/mm3

VB

/mm

0.002

0.004

0.008

0.01

Fig. 3 Effects of feed per tooth on the tool wear

Influence of axial depth of cut on tool wear

Fig. 4 shows that the tool wear under different axial depth of cut is studied. Other

cutting parameters are v= 37.6 m/ min, ae = 3.0 mm, fz = 0.08 mm/z. Under different

axial depth of cut, tool wear increase slowly with the increase of cutting length. When

the axial depth of cut is 0.2mm, the cutting amount of the cutting tool reaches the

maximum in several groups. When the VB value is 0.2mm, 0.4mm and 0.6mm, the

corresponding amount of material removal is 1160mm3, 1880mm3, 3600mm3

respectively. As for the tool wear behavior, a approximately linear tool wear

development with increasing material removal can be observed at the axial depth of cut

0.2mm. As the axial depth of cut increased, the heat generated and cutting force might

increase, so tool wear grows fast. The cutter edge breakage is mainly caused by tool

fatigue wear.

390

Advances in Abrasive Technology XX

0.1

0.2

0.3

0.4

0.5

0.6

0 500 1000 1500 2000 2500 3000 3500 4000

Material removal/mm3

VB

/mm

0.2

0.4

0.8

1.0

Fig. 4 Effects of axial depth of cut on the tool wear

Conclusions

1. The feed per tooth has the greatest influence on the milling force, and the effect of

the radial depth of cut is the least.

2. For milling Ni3Al-based superalloy with carbide coated milling cutter, suggested

the milling parameter combination are v = 37.6 m/ min, fz =0.004~0.008mm/min

and ap =0.2~0.8mm.

3. Axial depth of cut have great influence on tool wear. Since feed per tooth does not

increase tool wear rate noticeably, it can be increased according to the tool load to

get higher machining efficiency. Therefore, selecting proper axial depth of cut is

the key factors in extending tool life.

4. To reduce tool wear in milling Ni3Al-based superalloy with carbide coated milling

cutter, the recommended cutting parameters are fz ≤0.008 mm/ z, ap ≤0.4 mm.

391

Proceedings of the 20th International Symposium on Advances in Abrasive Technology 3-6 December, Okinawa, Japan

References

[1] Buergel R, Esser W, Grossmann J, et al. High temperature resistant part, made of

single-crystal or polycrystalline nickel-base superalloy: EP, EP1319729[P]. 2007.

[2] Pollock T M, Tin S. Nickel-Based Superalloys for Advanced Turbine Engines:

Chemistry, Microstructure and Properties[J]. Journal of Propulsion & Power, 2012,

22(2):361-374.

[3] Duhl D N, Cetel A D. Advanced high strength single crystal superalloy

compositions: CA, US4719080[P]. 1988.

[4] Lin C D, Kuo C P. Evaluation of the Machinability of Nickel-based Superalloy

with Coated Carbide Cutting Tools[J]. Journal of the Chinese Society of Mechanical

Engineers, Transactions of the Chinese Institute of Engineers - Series C, 2011,

32(3):227-234.

[5] Zhu D, Zhang X, Ding H. Tool wear characteristics in machining of nickel-based

superalloys[J]. International Journal of Machine Tools & Manufacture, 2013, 64(1):60-

77.

[6] Pawade R S, Joshi S S, Brahmankar P K, et al. An investigation of cutting forces

and surface damage in high-speed turning of Inconel 718[J]. Journal of Materials

Processing Technology, 2007, s 192-193(10):139-146.

[7] Pawade R. S., Suhas S. J, Brahmankar P. K., Rahman M, et al. An investigation of

cutting forces and surface damage in high-speed turning of Inconel 718[J]. Journal of

Materials Processing Technology, 2007, 2: 139-146.

[8] Liu G., Chen M.. and Shen Z. Experimental Studies on Machinability of Six Kinds

of Nickel-based Superalloys[J]. Machining and Machinability of Materials, 2006,

3:287-300.

[9] M. Nalbant, A. Altm, H. Gokkaya, The effect of cutting speed and cutting tool

geometry on machinability properties of nickel-base Inconel 718 super-alloys,

Materials and Design 28 (2007) 1334–1338.

[10] Xin M. Research on Cutting Performance of Fine Grain Cemented Carbide Insert

in Dry and High-speed Cutting of Fe-based Powder Metallurgy Part[J]. Tool

Engineering, 2006.

[11] Han LF, Qu SG (2007) Coated tools cutting wear mechanism of iron-based powder

metallurgy composite material. Machinery 45(1):7-12.

392

Advances in Abrasive Technology XX