Towards Improving Rock Cutting Tools Using Thermally Stable Diamond Composites

2009 ◽  
Vol 76-78 ◽  
pp. 585-590 ◽  
Author(s):  
Habib Alehossein ◽  
Xing S. Li ◽  
Jim N. Boland

Industrial application of synthetic diamond ceramics is growing very fast due to their super hardness, superb wear resistance and long-life durability. In rock, concrete and metal cutting, drilling, mining and quarrying and dimension stone industries, cutting tools made of diamond composites or impregnated diamond composite segments are gradually replacing the more commonly used cemented tungsten carbide (WC) tools. Through its SMARTCUT research program, CSIRO in the past 15 years has developed harder and stronger thermally stable diamond composite (TSDC) drag picks to encourage and help manufacturing and mining industries improve their cutting performance by replacing these traditional WC cutting tools with the new revolutionary TSDC tools. This improvement process however is much more complex than a simple material or cutting tool replacement, since the mechanism and configuration of cutting are substantially different in the two cutter head systems and its successful implementation requires a better understanding of the basics of rock cutting. Some of the factors influencing the differences are: cutter wear, fracture toughness, compressive and tensile strength, thermal properties, geometrical shape, spacing, angle of attack, rake angle, sharpness and bluntness characteristics, lacing design and cutter arrangements. Besides, it is most important to understand the relation between the tool or tool force and the fragmentation of the rock, which is the main focus of this paper.

2018 ◽  
Vol 936 ◽  
pp. 192-197 ◽  
Author(s):  
Yong Sun ◽  
Xing Sheng Li

Thermally Stable Diamond Composite (TSDC) tips have attracted a great attention of rock cutting industry due to the higher thermal stability and high wear resistance of TSDC. To make the TSDC tipped picks practical for real application, it is important to understand the failure behavior of the TSDC tips for rock cutting. One of the failure characters of TSDC tips is random failures. In this paper, a method is proposed to calculate the failure probability of TSDC tips for cutting individual rock segments. This method enables to link the segment length to the failure probability of the tip for cutting the segment. A numerical case study is presented to validate the method. The method can effectively reduce the impact of the number of segments on failure probability estimation accuracy.


2021 ◽  
Vol 878 ◽  
pp. 98-103
Author(s):  
Yong Sun ◽  
Xing Sheng Li ◽  
Hua Guo

Thermally Stable Diamond Composite (TSDC) has been used to make rock cutting tips to tackle the challenges of high cutting temperature and high abrasiveness met in hard rock cutting. Various research has been conducted to investigate the failure behaviour and predict the failure risk of the TSDC tips in real rock cutting operations. Based on the scenario of roadway development in underground coal mines, a series studies have been carried out to estimate the probability of TSDC tip sudden failure suffered from randomly occurring excessive bending force, which is one of major failure modes of the TSDC tips. This study aims to improve estimation accuracy of the failure probability by removing the constraint on roof rock thickness that has been adopted in existing research.


2014 ◽  
Vol 777 ◽  
pp. 165-170 ◽  
Author(s):  
Vladimir Luzin ◽  
James Boland ◽  
Maxim Avdeev ◽  
Xing Li

Diamond composite materials are being used increasingly in cutting tools for both the mining and manufacturing industries. Except for the low pressure CVD and SPS methods, most SiC based diamond composites are produced under high pressure and high temperature (HPHT). The dominant binder phase is SiC and these composites are classed as thermally stable and are referred to as TSDC (thermally stable diamond composite). TSDC composites are produced by reactive sintering either within the diamond stability field, ~1500°C and ~5.5 GPa, or in the graphite phase field at ~1550°C and ~2 - 3.5 GPa as originally patented by Ringwood. Unlike the traditional polycrystalline diamond composite (PCD) that use Co as the binder phase and operate under restricted temperature conditions, usually less the 800°C, TSDC is Co-free allowing the operational temperature range for TSDC to be extended substantially. Extensive experimental research has been conducted at the CSIRO (Commonwealth Scientific & Industrial Research Organization) Rock Cutting Laboratory to assess the quality of TSDC products through a series of in-house tests that have been developed (abrasive wear test, compressive and shear testing) to facilitate their use in the mining industry. The focus is to prevent TSDC from premature failures in drilling and cutting operations. Since the wear resistance and performance in general, of TSDC cutting elements are strongly dependent on the phase composition, phase distribution (microstructures) and phase interaction (microstresses), detailed studies of TSDC have been undertaken using optical, SEM (with EDS and CL), Raman microscopy and radiographic imaging of macro defects as well as x-ray and neutron diffraction. Residual stress measurements were made using the neutron diffractometer Kowari at OPAL research reactor in the diamond and SiC phases in two TSDC samples. The microstresses that developed in these phases as a result of quenching from high sintering pressure and temperature and the mismatch of the thermo-mechanical properties of SiC matrix and diamond inclusions were evaluated. The matrix-inclusion concept has also been used to calculate stress partition in the phases of the TSDC products that can be directly comparable with the experimental data and give clearer interpretation of the experimental results.


2020 ◽  
Vol 244 ◽  
pp. 448-453
Author(s):  
Oleg Trushkin ◽  
Hamzja Akchurin

Presently, there are no methods for calculating the parameters of the drilling practices with rock-cutting tools equipped with polycrystalline diamond composite (PDC cutters). To create such a method requires the studying their work. The article presents the results of bench studies of the PDC cutters in the process of a rock sample breakdown when reproducing the actual layout of the cutters on the working surface of the bit. An important parameter of PDC cutters operation, which is necessary for the bit load analysis, is the pressure of the cutters on the rock during its breakdown. The total pressure of a cutter on the rock can be broken into two mutually perpendicular components: the forcing pressure and the cutting pressure. It is proposed to evaluate the PDC cutters loading at breakage of rocks of different hardness using relative values of forcing and cutting pressures, which are calculated relative to the yield strength of the rock by the die. It is established that the variability of the average relative pressures of forcing and cutting is significantly influenced by drifting per bit turnover and the radius of the cutter on the bit. The dependences of the maximum relative pressures of PDC cutters at the plastic-brittle rock breakdown on the drifting per bit turnover and the radius of the cutter location on the bit are obtained. It has been established that when drifting up to 0.4 mm per turn, the main mechanism of breakdown is cutting, and with the increase of the breakdown depth, the process of forcing becomes decisive.


2019 ◽  
Vol 9 (16) ◽  
pp. 3294 ◽  
Author(s):  
Yong Sun ◽  
Xingsheng Li ◽  
Hua Guo

The Thermally Stable Diamond Composite (TSDC) tipped pick has been developed to replace Tungsten Carbide (WC) tipped picks for hard rock cutting. Due to the material properties of TSDC, a major failure mode of TSDC tipped picks during rock cutting is random failures caused by excessive bending force acting on the cutting tips. A probabilistic approach has been proposed to estimate the failure probability of picks with this failure mode. However, there are two limitations in existing research: only one drum revolution is considered, and the variation of rock thickness is ignored. This study aims to extend the current approach via removing these limitations, based on the failure probability analysis of picks over a full cutting cycle in the underground coal mining roadway development process. The research results show that both drum advance direction and the variation of rock thickness have significant impacts on pick failure probability. The extended approach can be used to estimate pick failure probability for more realistic scenarios in real applications with improved accuracy. Although the study focused on TSDC tipped picks, the developed approach can also be applied to other types of picks.


2020 ◽  
Vol 976 ◽  
pp. 62-68
Author(s):  
Yong Sun ◽  
Xing Sheng Li ◽  
Hua Guo

Thermally Stable Diamond Composite (TSDC) has high thermal stability and high wear resistance, and hence is potential to be used as cutting tips for hard rock cutting. Understanding the failure behavior of the TSDC tips during practical rock cutting is a key to enable the TSDC cutting tips to be applied successfully in mining and construction industries. Previous research has shown that the character of random failures due to excessive bending force on TSDC tips is of a major concern, and an approach to estimation of the failure probability of TSDC tips for cutting a rock segment has been developed. However, this approach requires the acquisition of the total cutting length of rock by a tip since it is brand new to it is failed, which can limit the application of the approach. In this paper, a simplified approach is proposed and compared with the existing approach through a numerical case study.


Author(s):  
I V Shvetsov ◽  
B Ya Mokritskij ◽  
O A Malukhina ◽  
A H Rahmonov ◽  
V N Belyakov

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.


2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.


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