Cutting performance and wear mechanisms of Sialon ceramic cutting tools at high speed dry turning of gray cast iron

doi:10.1016/j.ijrmhm.2015.08.007

International Journal of Refractory Metals and Hard Materials

Volume 54, January 2016, Pages 330-334

$International Journal of Refractory Metals and Hard Materials$

https://doi.org/10.1016/j.ijrmhm.2015.08.007 Get rights and content

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The highlight of this paper was to reveal the relationship between cutting performance and wear mechanisms at high speed dry turning of gray cast iron.

Abstract

In the present work, the phase composition and microstructure of two Sialon cutting inserts (named sample A and sample B) were characterized by XRD and SEM. The cutting performance and wear mechanism of the cutting inserts were investigated at high-speed dry turning of gray cast iron. The results showed that the main phases of them were α- and β-Sialon, and the sample A contained more α-Sialon than that of sample B. The grains of the Sialon cutting inserts are mainly elongated shape, and the aspect ratios are about 5.32 and 5.09, respectively. The tool life of sample B was longer than that of sample A at low speed. However, with the speeds increased, the tool life of sample A was getting closer to that of sample B and then exceeded that of sample B. The wear mechanisms of the two cutting inserts were abrasive and adhesive wear, however, as the cutting speeds increased, the dominant wear mechanisms were different.

Introduction

The high speed machining has been widely used in aerospace and mold manufacture because of its lower cutting cost and good mechanical properties of the cutting tools [1], [2], [3]. Therefore, the mechanical properties of cutting tools become the key factors to ensure the machining efficiency. Ceramic cutting tools have already been widely used for machining hard materials due to their unique mechanical properties [4], [5], [6], such as silicon nitride (Si₃N₄) ceramic cutting tools, which have became the promising ceramic cutting tools because of their high hardness, strength, and fracture toughness [7], [8], [9], [10]. However, the limitations of their applications are insufficient wear resistance and inferior thermal shock resistance, which will cause high wear rate [11], [12].

To obtain good wear resistance ceramic cutting tools, a silicon nitride based ceramic cutting tool was introduced. As a solid solution of silicon nitride, Sialon ceramic has been researched and developed in the last three decades on a wide variety of engineering applications, especially for the cutting tools [13], [14]. Due to their high fracture toughness, high thermal conductivity, high wear resistance, and super chemical mechanical stabilities at elevated temperature, Sialon ceramic cutting tools can show reliable cutting performance during high speed turning of gray cast iron [15], [16], [17], [18].

In the past, some research works had been done on cutting performance and tool life of Sialon ceramic cutting tools. H. Mandal et al. [19] studied the cutting performance of new α/β-Sialon ceramic cutting insert in turning of gray cast iron. Because of its high hardness, it would reduce tool wear rate and increase tool life in comparison with some commercial ceramic cutting inserts. B. Bitterlich and his co-workers [20] reported a particle-reinforced Sialon material cutting insert. It was proved that improving fracture toughness without sacrificing its hardness could lead to increasing the wear resistance and tool life. There is a close relationship between cutting performance and wear mechanisms and it is necessary to research them carefully. So far, the studies of the relation between cutting performance and wear mechanisms of Sialon ceramic cutting tool were more but not carry the aspects of the news. In the aspects of high speed dry turning of gray cast iron should be carefully studied.

The goal of the present investigations was to reveal the relationship between mechanical properties and cutting performance. Two Sialon ceramic cutting inserts which were obviously different in microstructures were selected for a comparison via high-speed turning gray cast iron in dry condition. Worn surfaces of the cutting inserts after turning tests were characterized by means of scanning electric microscope (SEM) and energy dispersive spectroscopy (EDS) to study the wear mechanisms.

Section snippets

Material testing

Two kinds of Sialon cutting inserts were chosen to investigate in this study. The density was measured by Archimedes' method in distilled water. The cross section of cutting inserts was mirror polished and then indented with 98 N load for 10 s by Vickers hardness tester (HXD-10000TM/LCD, China) with a diamond Vickers indenter at room temperature. At least ten indentations were made for each insert. The hardness and fracture toughness of the cutting inserts were calculated by Charles and Evans

Properties and microstructures

Two XRD patterns of the cutting inserts are shown in Fig. 1. It can be seen that the main phases of the two cutting inserts are all β-Sialon (Si₅AlON₇) and α-Sialon (Y_0.67Si_8.8Al_3.2O_1.2N_14.8). The phase ratios of α/β-Sialon of sample A and sample B are about 10:90 and 2:98, respectively. In addition, Y₄SiAlO₈N is detected as the grain boundary phase in both cutting inserts. And the peak intensity of Y₄SiAlO₈N in the sample B is weaker than that of in the sample A, it means that the content of

Conclusions

The cutting performance and wear mechanisms of two commercial Sialon ceramic inserts were studied via different high speed turning of gray cast iron. From the studies, the following conclusions could be made:

(1)
The phases of the two cutting inserts were mainly β-Sialon and α-Sialon.
(2)
Sample A had higher Vickers hardness but lower fracture toughness than that of sample B.
(3)
The tool life sample B was longer than that of sample A at lower speed, as the cutting speed increased, the tool life of sample A

Acknowledgments

The present work was financially supported by Project on the Integration of Industry, Education and Research of Guangdong Province (Grant No. 2011A090200080) and The China Postdoctoral Science Foundation (Grant No. 2014M560656).

References (23)

Y. long et al.
Microstructure of TiAlN and CrAlN coatings and cutting performance of coated silicon nitride inserts in cast iron turning
Ceram. Int.
(2014)
J. Qin et al.
Continuous and varied depth-of-cut turning of gray cast iron by using uncoated and TiN/Al₂O₃ coated silicon nitride-based ceramics tools
Ceram. Int.
(2014)
C.H. Xu et al.
Wear behavior of Al₂O₃/Ti(C,N)/SiC new ceramic tool material when machining tool steel and cast iron
J. Mater. Process. Technol.
(2009)
J.V.C. Souza et al.
Cutting forces in turning of gray cast iron using silicon nitride based cutting tool
Mater. Des.
(2009)
R.P. Martinho et al.
Wear behaviour of uncoated and diamond coated Si₃N₄ tools under severe turning conditions
Wear
(2007)
J. Gubicza et al.
Mechanical properties of oxidized silicon nitride ceramics
Mater. Sci. Eng. A
(1999)
Y. long et al.
Cutting performance and wear mechanism of Ti–Al–N/Al–Cr–O coated silicon nitride ceramic cutting inserts
Ceram. Int.
(2014)
W. Grzesik et al.
Documentation of tool wear progress in the machining of nodular ductile with silicon nitride-based ceramic tool
Manuf. Technol.
(2011)
C. Tian et al.
Thermal shock behavior of Si₃N₄–TiN nano-composites
Int. J. Refract. Met. Hard Mater.
(2011)
V.A. Izhevskiy et al.
Progress in SiAlON ceramics
J. Eur. Ceram. Soc.
(2000)

S. Kurama et al.

Wear properties of α- and α/β-SiAlON ceramics obtained by gas pressure sintering and spark plasma sintering

J. Eur. Ceram. Soc.

(2011)

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Sialon materials have obtained a lot of attention due to their superior physical and chemical properties, such as high hardness, high strength, excellent oxidation resistance, high-temperature stability, outstanding wear resistance, chemical inertness [1–3]. They have been successfully utilized for broad applications, including cutting tools, wear components, bearings, and mechanical face seals for drainable pumps [4,5]. However, compared with metals and polymers, the applications of ceramics are still limited by their inherent brittleness and poor tribological properties [6].
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This paper focused on the comparative study on the crater wear when cutting flake graphite iron (FGI), compacted graphite iron (CGI) and nodular graphite iron (NGI) because of the reported overwhelming difference in tool life. A series of turning experiments are conducted with FGI, CGI and NGI, with multilayer coated inserts under dry condition. The crater wear profiles obtained from the confocal microscopy are collected to construct the evolution of crater wear. Together with the rake temperature estimated by Finite Element Analysis (FEA) under various cutting conditions, the crater wear data indicated that one unified crater wear model can be constructed by combining two most dominant wear mechanisms, 3-body abrasion and dissolution. The maximum crater depth from the experimentally measured 3D crater profiles and the maximum cutting temperatures from FEM simulations are used to estimate the contributions from the abrasive and dissolution wear. Therefore, the same crater wear mechanisms are involved when cutting FGI, CGI and NGI and the main difference in wear comes from the cutting temperature difference in machining three cast irons.
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Cutting performance and wear mechanisms of Sialon ceramic cutting tools at high speed dry turning of gray cast iron

Highlight

Abstract

Introduction

Section snippets

Material testing

Properties and microstructures

Conclusions

Acknowledgments

Ceram. Int.

Ceram. Int.

J. Mater. Process. Technol.

Mater. Des.

Wear

Mater. Sci. Eng. A

Ceram. Int.

Manuf. Technol.

Int. J. Refract. Met. Hard Mater.

J. Eur. Ceram. Soc.

J. Eur. Ceram. Soc.