Diamond Segments Research Articles

Сравнительный прочностной анализ алмазных сегментов канатных камнерезных станков

The paper discusses the different shapes of diamond segments for stone cutting machines. The purpose of this research is to find ways to improve the abrasion resistance of the diamond segments, reduce the vibration load and increase the cutting efficiency. The operating conditions of stone-cutting machines are analysed, as well as the ways of increasing the efficiency of diamond segments by changing their shape. A calculation of the loads arising during operation of the diamond segments is made, and the results are verified using an experimental setup. The initial shape is analysed and the stresses that exceed the material parameters are found. In order to reduce the stresses, a diamond segment with rounded edges is simulated. Segments with bevelled edges and conical shape are also considered. Based on the experimental results, it is found that one of the promising shapes is that with rounded edges.

Understanding the wear mechanisms of diamond circular saw blades during machining hard rocks

Hard rock, prized for its exceptional resistance to corrosion and pollution, is extensively utilized in construction and transportation. However, its high hardness poses a significant challenge to the limited lifespan of diamond tools. This study delves into the wear mechanisms affecting diamond circular saw blades during hard rock machining. Initially, the dynamic behavior of saw blades was analyzed to uncover the wear and breakage characteristics of diamond segments. Through systematic characterization, the wear mechanisms and chemical element deposition were elucidated. The findings reveal that the front segment gradually loses sharpness due to primary rock impact, primarily experiencing bond wear, abrasive wear, and pull-out, while the rear segment encounters mainly abrasive and bond wear. Fresh and whole diamonds are approximately 45% with around 25% exhibiting macro-fractures and pull-out at the front segment, whereas the rear segment comprises over 50% fresh diamonds, with less than 20% showing macro-fractures and pull-out. Side edges predominantly undergo abrasive wear, bond wear, and pull-out or breakage, while medium edges experience abrasive wear, bond layer wear, and wear equalization. The rock is removed in a brittle and partly elastic-plastic manner. Through a comprehensive investigation, the wear process of diamond segments was clarified, attributing diamond wear to vibration shock, fatigue wear, and grinding heat, while bond wear factors include debris hardening point, fatigue wear, and chemical erosion. These systematic findings shed light on the wear characteristics of diamond segments, serving as a crucial theoretical guide for the material design of diamond segments for machining hard rocks.

Wear mechanisms of diamond segmenta in cutting of carbon fiber reinforced cement-based composite and optimizing in parameters

Carbon fiber reinforced cement-based composite material (CFRC) is a novel type of composite material that involves the incorporation of carbon fibers into ordinary concrete. This addition effectively enhances the tensile strength, deformation performance, and dynamic load resistance of reinforced concrete structures. Consequently, CFRC has found increasing applications in the construction industry. The objective of this research is to investigate the wear mechanisms of diamond tools during the sawing process of CFRC and offer guidance on cost reduction through the optimization of processing parameters. The wear analysis of diamond segments can be divided into two categories: matrix wear and diamond particle wear. The diamond particles can exist in different states, and the formation of voids resulting from the detachment of diamond particles is considered as a reference point. The analysis reveals that abrasive wear is the main mechanisms of matrix wear in CFRC sawing. The wear resistance is strongly influenced by the proportion of diamond particles in favorable states, which is determined by the applied loads and operating parameters. The proportion of diamond particles exhibits a clear variation with adjustments made to the feeding speed. Notably, an increase in feeding rate results in a significant decrease in the percentage of blunt particles, reducing it from 28% to 6%. To achieve a lower wear rate, a predictive model was established using Design Expert software based on the experimental results. The model demonstrated that a wear rate as low as 268.5 mm/m2 can be achieved with a flywheel speed of 78 r/min and a feeding speed of 90 mm/h. The optimization process, aimed at minimizing wear rate, was successfully carried out without compromising productivity.

Effect of rock properties on wear and cutting performance of multi blade circular saw with iron based multi-layer diamond segments

This study is an attempt for comprehensive, combining experimental data with advanced analytical techniques and machine learning for a thorough understanding of the factors influencing the wear and cutting performance of multi-blade diamond disc cutters on granite blocks. A series of sawing experiments were performed to evaluate the wear and cutting performance of multi blade diamond disc cutters with varying diameters in the processing of large-sized granite blocks. The multi-layer diamond segments comprising the Iron (Fe) based metal matrix were brazed on the sawing blades. The segment’s wear was studied through micrographs and data obtained from the Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDS). Granite rock samples of nine varieties were tested in the laboratory to determine the quantitative rock parameters. The contribution of individual rock parameters and their combined effects on wear and cutting performance of multi blade saw were correlated using statistical machine learning methods. Moreover, predictive models were developed to estimate the wear and cutting rate based on the most significant rock properties. The point load strength index, uniaxial compressive strength, and deformability, Cerchar abrasivity index, and Cerchar hardness index were found to be the significant variables affecting the sawing performance.

Investigation of Dry Sliding Wear Behavior of Different Diamond Segments with Response Surface Methodology

Investigation of Dry Sliding Wear Behavior of Different Diamond Segments with Response Surface Methodology

The wear behaviour of different metallic bond alloys tested in a modified B611-13 test in an acidic, neutral and alkaline media

The abrasive and adhesive wear behaviour of metallic bonds can be significantly affected by varying pH values of the attacking medium. However, the knowledge about the pH value influence on diamond impregnated bits used in core drilling industry is still limited. One recent publication shows the advantage of modifying a standard ASTM B611-13 test to investigate the abrasive and adhesive wear behaviour of a diamond segment bond material in a neutral regime (pH7). This study mainly focuses on the effects of a varying surrounding media on the tribological behaviour using an acidic, neutral and alkaline slurry. This emulates more aggressive conditions for the diamond segments used in mining as well as construction industry. The pH value at which such diamond segments operate can differ from pH2 up to a value of pH13. The present work studies the wear behaviour of two metallic bonds in a modified B611-13 arrangement at 4 m/s sliding speed and different pH values. The tested specimens are investigated with regard to their change in mass and microstructure at the sliding interface zone. The results reveal a significant influence of the pH value on the wear behaviour of the bond system.

Experimental study and smoothed particle hydrodynamics simulation of synthetic diamond grit scratching on steel

Superabrasives like synthetic diamonds are indispensable in today’s construction industry, particularly for core drilling applications in reinforced concrete. The increase of the cutting efficiency of such core bits strongly depends on the material removal behavior of single diamond grains placed in a diamond segment acting as cutting elements. Therefore, this paper presents a newly developed experimental setup for a 3-mm single diamond grain scratch test, as well as the application of a Smoothed Particle Hydrodynamics (SPH) method to model single diamond grains scratching a rebar base material at operational parameters. Diamonds in two main different crystallographic and geometric orientations are tested and investigated with respect to their forces and temperatures at the cutting edge. Furthermore, the chip formation and different material removal mechanisms are analyzed for each orientation and compared with the model output. Validation tests and sensitivity analyses are performed in 3D and high resolution, thanks to the runtime acceleration of SPH through parallel computing on the graphics card. The results indicate: 1) A significantly different material removal behavior as a result of changing the diamond orientation; 2) The capability and high efficiency of SPH for modeling single grain scratch tests.

Analysis of diamond wear morphology and segment wear evolution during the process of hard granite sawing

Diamond circular sawblade has been widely used in hard granite processing. In this study, the wear mechanism and wear evolution of the diamond segment were investigated. The wear morphologies of diamond grits were classified as emerging diamond, whole diamond, crack diamond, blunt diamond, micro-fractured diamond, macro-fractured diamond, wear flat diamond, and pull-out diamond, which is based on sufficient observation data. The main form of diamond wear is fracture. The fracture morphology of diamond grit dominates by cleavage, which is brittle transgranular fractures, and the microscopic features are fracture steps and river-like patterns. Since the {111} crystal plane has the largest interplanar spacing among all the crystal planes, cleavage fractures tend to occur on this crystal plane. Through the scratches and pitting on the diamond grit surface, it proved that the wear process is a mixed type of two-body wear and three-body wear. However, some diamond grits exhibit special fracture morphology and are without the typical characteristics of cleavage fracture. Combined with internal factors (including microstructures and internal defect) and external factors (including chip flow, thermal load and mechanical load), the mechanism of various diamond wear morphologies and segment wear phenomena observed in the sawing experiment is clarified. Finally, the evolution process of the diamond failure and segment wear are described. The research systematically revealed the mechanism of segment wear and the fracture morphology characteristics of diamond grits in the sawing granites, which can further improve the understanding of segment wear and provide theoretical guidance for segment design.

Diamond investments – Is the market free from multiple price bubbles?

The following study aims to investigate whether multiple price bubbles, in which the quoted market price of diamonds significantly deviates from their fundamental value, exist in the diamond market. It was conducted using ADF, SADF and GSADF tests, with the latter found to be an optimal form of evaluating the analysed issue.The presented results support the conclusion that the diamond market is not free from periods defined as price bubbles. The study revealed price bubbles related to the leading, albeit declining in recent years, position of De Beers within the market and its activities, the financial crisis of 2008, the subsequent European debt crisis, and the crisis caused by the aggression of the Russian Federation against Ukraine in 2022. However, the identified periods of speculative bubbles in the diamond market are short and tend to affect the rough diamond segment earlier than the broader diamond market.

Microstructure and performance of glass fiber metal composite-bonded diamond segment with Cu-Sn-Ti alloy

To develop metal-bonded diamond tools without dressing during machining, a novel glass fiber metal composite bonding agent with Cu–Sn–Ti alloy was proposed. The three-point bending strength of the diamond segments and the Vickers microhardness of the solidified composite bonding agents were tested. The microstructures of the diamond segments were investigated and the wear tests were performed for each group of diamond segments. The results showed that diamond segments with glass fiber content of 1.55 wt % - 6.89 wt % exhibited lower bending strength (declined by 36.4%–80.4%) and smaller microhardness (reduced by 16.0%–87.9%), compared to those of the diamond segment with no glass fiber addition. Good bonds were formed among the Cu–Sn–Ti alloy, glass fibers, and diamond grits. Chemical reactions occurred between the Cu–Sn–Ti alloy and glass fibers during high-temperature brazing, forming new intermetallic compounds such as Ti5Si3, Ti2O3, and Ti(Cu, Al)2, which improved the bonding strength. With an increase in the glass fiber content, fractures were more likely to occur in the glass fibers than in the diamonds, resulting in the bending strength decreasing more and more slowly. The wear resistance of the diamond segments decreased gradually with increasing glass fibers weight content. The diamond segment with 4.98 wt % glass fibers exhibited the best and most stable wear performance.

Microstructure and mechanical properties of vacuum brazed diamond abrasive segments with zirconium carbide reinforced Cu-based active filler metals

Herein, by using Cu–Sn–Ti alloys addition zirconium carbide (ZrC) reinforcement to provide a way of enhancing the strength of brazed joint between diamond and solder. Microtopography of brazed segments was observed and interfacial characteristics of the brazing diamond were analyzed in detail via Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The wear machining performance of the diamond segment at different braze process was measured by changing the brazing temperature and holding time, respectively. Experiments indicated the microtopography of brazed segments with composite alloy of 15 wt% ZrC addition was optimal which the diamond edge was obvious, and the brazing filler metal spread more continuously and uniformly around the diamond without cracks and holes. Interfacial characterization results indicated that 10% wt% ZrC addition can promote titanium carbides produced on the diamond surface owing to the capillary force can improve the wettability. 15% wt% ZrC addition can further promote titanium carbides produced and improve the wettability by increasing the capillary force. However, higher ZrC addition (x ≥ 20 wt%) reduced performance of welded joints. Different braze process results showed that the brazed joint with the best grinding performance was obtained when the brazing temperature was 980 °C and the holding time was 15 min.

The abrasion resistance of brazed diamond using Cu–Sn–Ti composite alloys reinforced with boron carbide

Cu–Sn–Ti filler is commonly used in industrial production to prepare diamond tools. However, the hardness and strength of the Cu-based brazing filler metal are low, resulting in poor wear resistance of the brazing filler metal. In this work, novel brazed diamond segments were fabricated using Cu-Sn-Ti-xB4C composite fillers. The correlation between the interfacial compounds and friction and wear performance was studied. The results showed that after adding B4C with 2 wt%, B4C can react with the Cu-Sn-Ti filler, which moderates the wetting reaction between the active alloy and the diamond particles during brazing. The exposure of diamond was high and no obvious thermal damage occurred. The layered compounds is formed on the interface of the diamond; the SEM and XRD characterization prove that the compounds generated on the diamond surface is TiC. Vickers hardness tester was used to measure the microhardness of the fillers layer and the interface layer, and the hardness value of the filler layer gradually increased with the increase of B4C content. When the addition of B4C is 2%, the hardness value of the interfacial layer reaches 255 HV0.05. The friction and wear experiments results showed that when B4C was added at 2%, the wear material removal was 0.189 g and the wear resistance of the brazed specimens was optimal.

Wear behavior and morphologic characterization of diamond segments induced by crystal plane characteristics of diamond grits in sawing hard materials

The wear of diamond grains (DGs) is a classic problem, affects the final cost, in sawing hard materials (granitic rocks) for slabs. However, the previous research rarely pays attention to study the wear of DGs considering the crystal plane characteristics. Hence, in this study, the aim is to explain the fracture morphology of DGs in sawing granitic rocks taking into account the crystal plane characteristics. The wear experiment was carried out with a frame saw. Then the surface morphology of DGs was characterized by scanning electron microscope (SEM). According to wear characteristics of DGs, the wear of DGs was divided into seven different types, including fresh, whole, micro fractured, pulled-out, flush with matrix, macro fractured and blunt. Interestingly, the bottom surface of the pulled-out DGs in contact with the matrix was mostly {100} crystal planes that account for approximately 80%. In addition, flush with matrix mostly occurred on the {111} crystal planes (account for 90%), and mostly at both ends of the diamond segments (DSs). Then, this phenomenon is explained by the interplanar spacing of DGs. Moreover, wear behavior and morphologic characterization of DGs were discussed considering the factors of stone sawing (e.g., detritus) and the characteristics of DGs (e.g., dislocation). Finally, wear evolution mechanism of DSs topography were proposed. This research enhances to deeply understand the wear of DGs in granite processing and provides guidance for the design of DSs.

Adding Hf element to improve the strength and wear resistance of diamond brazed with Ni-based boron-free brazing filler metal

Nickel-based filler is a very important brazing material with excellent corrosion resistance and strong hardness. However, its high-temperature thermal damage, graphitization and multiple brittle phases are still problems to be solved. In this work, the NiCrSiCuSn boron-free brazing filler metal is reinforced by adding different contents of Hf element. The microstructure of the filler and morphology of the diamond were analyzed by scanning electron microscope and energy dispersive spectroscopy. The phase composition of the brazed joint is characterized by X-ray diffraction. The alloy segments and brazed diamond segments were performed by the vickers microhardness tester and the friction and wear tester, respectively. The results show that when 1 wt% Hf is added to Ni-based boron-free filler, the melting point of the filler is the lowest and the crystal grains are also refined. At the same time, chromium carbide is formed between diamond and brazing material, so they are closely connected. Compared with other components, brazed diamond with 1 wt% Hf brazing filler metal has the best exposure, higher joint strength and wear resistance, and a lower degree of graphitization. The morphology of the bonding surface and the wear surface shows that the addition of 1 wt% Hf reduces the thermal damage of the diamond.In turn, the mechanical properties of the joint are optimized.

Experimental investigation on granite cutting by means of diamond frame saw

A series of sawing experiments on granite was carried out to explore the cutting performance of a diamond frame saw with the horizontal reciprocating cutting mode. A model of the average thickness of the cutting chip was established and the characteristics of cutting forces were analyzed. The wear mechanism of segments was revealed by analyzing the width of the saw kerf and the wear morphology of the diamond segments. The results demonstrated that the wear resistance and the cutting forces increased with the feed speed. The cutting forces changed abruptly at the reversing point during granite cutting. Meanwhile, the proportion of macro-fractured and pulled-out diamond particles and the mean wear rate of segments increased with the feed speed, and the mean protrusion height of diamond particles was less than 100 μm. The width of the saw kerf reduced gradually during the sawing progress, forming a cone that is wide at the top and narrow at the bottom. Furthermore, the investigations proved that the wear of the segments remains consistent in two directions (y, z). An increasingly apparent phenomenon of protruding diamond particles appears on the side surface of the segment with the increase of feed speed. The research can provide certain data support for granite cutting and lay the foundation for the subsequent optimization of the equipment.

Diamond tool wear monitoring by sensory analysis in milling of absolute black granite

Diamond tools suitable for machining operations of natural stones can be divided into two groups: cutting tools, including blades, the circular blades and the wires, and the surface machining ones, involving mills and grinders, that can be of different shapes. For the stone sawing process, the most adopted tool type is the diamond mill, whose duration and performance are influenced by various elements such as: the mineralogical characteristics of the material to be machined; the working conditions such as the depth of cut, the feed rate and the spindle speed; the production process of the diamond segment and the characteristics of both the matrix and the diamond, such as the size, the type and the concentration of the diamonds and the metal bond formulation hardness. This work allows to indirectly assess the wear of sintered diamond tools by signal analysis (in time and frequency domain) of the cutting force components acquired in the process. The results obtained represent a fundamental step for the development of a sensory supervision system capable of assessing the tool wear and hence to modify the process parameters in process, in order to optimize cutting performance and tool life.

Применение метода многокритериального синтеза в решении задач по обеспечению пожарной безопасности

Purpose. Increasing the efficiency of scientific research and solving applied problems in the field of fire safety by introducing a computational computer experiment – the method of multi-criteria synthesis to reduce the time, material and labor costs for the experiment and provide correct systemic interpretation of test results. Methods. To solve the problems of fire safety, the method of multi-criteria synthesis was applied. It makes it possi-ble to predict the behavior of the system, taking into account the stochasticity of its parameters and the choice of rational characteristics that provide the required output parameters. The search for the optimal set of parameters of a technical object involves the determination of the calculated values of the criteria by the values of the calculated points, which are located in the multidimensional space of variable parameters. In this case, the space of parameters is transformed into the space of criteria, taking into ac-count the accepted restrictions. Findings. The article provides examples of the application of the method of multi-criteria synthesis in solving problems of ensuring fire safety. The formulation of a fire retardant and fire extinguishing composition based on synthetic phosphates of bivalent and trivalent ammonium metals, being highly effective in impact on peat and wood, was determined. The using of an optimization-simulation approach made it possible to predict the time of extinguishing a fire in a tank and to select the optimal parameters of extinguishing by supply of low expansion foam directly into the fuel layer. On the basis of multi-criteria computer synthesis, the concentration of the modifying additive in the set of diamond segments and the cutting conditions for the tool during emergency rescue operations was determined. The way of assessing the aggregate territorial risk by the method of statistical modeling was developed which created a framework for risk management, including legal, economic regulation and compulsory insurance. Application field of research. The presented research results are aimed at improving the fire safety of various objects.

Analysing the life index of diamond cutting tools for marble building stones based on laboratory and field investigations

Cutting tool wear constitutes one of the principal parameters in the processing cost of building stone. The life index of the cutting tool is obtained by evaluating the wear of diamond segments in the processing plants and examining the main parameters thereof. The purpose of this study is to determine the life index of the diamond cutting tool by considering the physico-mechanical properties of marble stones and the operational parameter of cutting speed. To this end, a dataset was provided by collecting the data from eight building stone processing plants in the provinces of Tehran, Isfahan, and Yazd of Iran. In this regard, the number of square metres of building stone that every diamond cutting tool can cut during its lifetime is defined as the cutting tool life index (TLI). After collecting the required data, SPSS software was employed for statistical analysis. The results revealed that the Brazilian tensile strength is the main parameter that affects the cutting tool life index. Linear and non-linear regression analyses were then considered for the development of predictive models for the TLI based on the Brazilian tensile strength. The performance of the developed models was subsequently examined by using three different criteria: the coefficient of determination, the variance accounted for, and the root-mean-square error. The results of this study show that the non-linear predictive model of the TLI presents a very good performance, and thus, the diamond cutting tool life index can be obtained for marble stones by considering the model developed herein.

Wear characteristics of diamond segments on multi-blade combination saw with different diameters in granite sawing

In this paper, the wear characteristics of diamond segments adopted to multi-blade combination circular saw with different diameters were compared and investigated in the process of granite through an experiment. Load model with a diameter as the variable of combination saw was established based on the maximum undeformed chip thickness of a single particle. Combined with the load model, scanning electron microscope, laser microscope and vernier calipers were used to comprehensively analyze the wear characteristics of segment form the aspects of the wear morphology of diamond and metal matrix, the particle protrusion height, and the abrasion loss of segment. The results indicated that load nonuniformity of diamond generated by diameters change of saw blade was the main reason for segment wear discrepancy of large and small diameter saw blade when rocks were sawed by combination saw, and abrasion loss of segment adopted to small diameter saw blade was significantly higher than that of large-diameter saw blade. Diameter variation of saw blade in combination saw caused the different wear mechanism of diamond in segment, pulled-out and macro-fractured crystals were dominant in small-diameter saw blade, then the proportion of whole particles increased in segment used to the saw blade of large diameter. Particle protrusion height was related to the diameter in the combination saw. The high protrusion height of particles existed in the large-diameter saw blade.

Evaluation of rock cutting performance of diamond segmented frame saw in terms of diamond segment wear

Diamond segmented frame saws are used to produce slab from natural stone blocks in stone processing plants. Diamond segments welded on flat steel blades are utilized for rock block cutting in frame saws. Segment wear (SW) affects cutting performance. Physical and mechanical rock properties and advance rate (AR) play a significant role in SW. Therefore, the relationship between SW, AR, and rock properties should be determined to achieve effective cutting. Low SW and high AR yield the most effective cutting. This study employed marble blocks cut in a large-scale diamond segmented frame saw to determine diamond SW and AR for each cutting process to determine the effects of physical and mechanical rock properties and AR on diamond SW. Advance rate, tensile and impact strengths, Shore hardness, modulus of elasticity, and block weight were used to develop a prediction model for SW. For SW, this study proposed an AR-based prediction chart that can be used to provide effective cutting conditions (lowest SW and highest AR) in diamond segmented frame saws.