Carbide Tip Research Articles

Development of the technology of restoration of the tail part of the body of the cutter of the road cutter

Purpose. The purpose of this work is to study the patterns of wear and develop a technology for restoring the tail part of the cutter body of the road cutter. They conducted an analysis of the wear of the cutters and found that most of them are suitable for use, since the shape of the carbide tip has not changed much and can still be used for grinding asphalt-concrete mixture. Methodology/approach. The method of restoration of the caudal part of the body of the incisors was developed and proposed. The recovery route is as follows: 1. Cleaning the incisor. 2. Heating the tail part of the cutter with a propane-oxygen flame. 3. Plastic deformation of the cutter body in the die. 4. Air cooling. 5. Control measurement of size changes. The recommended heat treatment temperature for plastic deformation depends on the concentration of carbon and alloying elements of the steel, and lies in the temperature range from 800 to 1280°С, the heating time is 1.33 min. Before distribution, the body of the cutter was heated using a propane-oxygen flame. Deposition was carried out in a closed die with the help of a special Poisson. A cutter head was placed in the matrix, on which a guide with a punch was installed. The developed technology of restoration of the tail part of the incisor by handing. Findings. According to the proposed technology, the tail part of the cutter body is distributed from 0.04 mm to 0.73 mm per side. Research limitations/implications. In this way, the cutters of the road cutters are restored to almost the dimensions of a new part, which enables repeated use.

Homogenization Treatment and Plastic Deformation Improve the Carbide Homogeneity of M42 High‐Speed Steel

The mechanical properties of high‐speed steel (HSS) are significantly influenced by the distribution of carbides formed during solidification. Despite extensive research, the nonuniform cooling in large ingots remains an area requiring further investigation. In this study, the microstructure inhomogeneity in M42 HSS with a diameter of 330 mm is examined. Models are developed to predict the dissolution of carbide networks during homogenization, achieving a 39% reduction in hardness variation (Δr) between the center and surface. Further improvements are attained through hot forging and rolling, leading to the fragmentation of the carbide network into a banded structure. Additionally, a detailed carbide tip dissolution model is established, providing a reliable basis for optimizing annealing processes. As a result, the carbide distribution converges significantly, with hardness variations reduced by 88% to only 0.3 hardness Rockwell C scale, showcasing substantial enhancement in material homogeneity.

Effect of Some Cutting Parameters on Surface Finish of Bright Mild Steel

The objective of this paper was to evaluate the effect of some cutting parameters on surface finish of bright mild steel (BMS). Samples were cut into the required piece with dimension 50mm x 200mm and the turning operation done using a tungsten carbide tip tool. The cutting variables include speed of the spindle, feed rate and depth of cut. The result obtained shows that a feed rate of 0.75mm/rev affects the surface finish the most with a roughness value of 3µm, while the combination of a depth of cut of 0.2mm and maximum speed 700rpm have the minimum effect on the surface finish (Ra value of 1.1µm) of low carbon steel.

EFFECT OF QUENCHING HOLDING TIME ON MICROSTRUCTURE AND PROPERTIES OF HIGH SILICON HYPEREUTECTIC HIGH CHROMIUM CAST IRON

In this paper, the effects of different quenching holding times on the microstructure and properties of high-silicon hypereutectic high-chromium cast iron (Fe–4.0C–35.0Cr–1.9Si) were investigated. The effect of quenching holding time on the microstructure of high silicon hypereutectic high chromium cast iron was analyzed by optical microscope, scanning electron microscope and X-ray diffractometer. The hardness and wear resistance of high-silicon hypereutectic high-chromium cast iron quenched at 1150∘C for different time were tested by Rockwell hardness tester, microhardness tester and wear tester. The results show that the microstructure of as-cast high-silicon hypereutectic high-chromium cast iron is mainly composed of pearlite matrix and M7C3 carbide. Quenching heat treatment makes part of the matrix transform from pearlite to martensite, and precipitate a small amount of M[Formula: see text]C6 type secondary carbide. With the increase of quenching holding time from 1[Formula: see text]h to 6[Formula: see text]h, the amount of martensite transformation gradually increases, the primary carbide has no obvious change, the eutectic carbide tip dissolves, and the morphology gradually becomes smooth. The hardness and wear resistance both increase first and then decrease. After 4 hours of insulation, the hardness reaches the highest 60.5HRC, which is increased by 3 HRC compared to 1 hour of insulation. The wear resistance increases by 22.1% compared to 1 hour of insulation. At this time, the wear resistance is the best.

Effects of Ni-based composite coatings on failure mechanism and wear resistance of cutting picks on coal shearer machine

The performability and wear resistance of the cutting picks play an important role in the extraction operation of mining machinery especially drum shearers in longwall coal mines. Tungsten carbide tip fracture and removal, and severe wear of the pick body are the major failures that affect the performance of these picks. The coating could be a proper solution for strengthening the coal-cutting tools and extension of their useful life. In this paper, a Ni-based ultrafine coating, NiBSiFeWC, deposited by laser-cladding technique, has been applied to improve the wear resistance and mechanical properties of the coal-cutting picks. All cutting tests were carried out on a drum shearer machine and on a real-scale operation, which makes the study much more realistic and effectively applicable for advanced tools’ developments in mechanized longwall mines. The archived results show that NiBSiFeWC coating reduced the tool wear rate by about 50%.

Wear out effect for cutting element of milling machine on asphalt concrete cutting strength

Introduction. This article presents the results of a study of the wear out effect the carbide tip for the cutting element of a milling machine on the resulting cutting strength when milling asphalt concrete. The relevance of the work is due to insufficient information about the wear out effect on the strength of cutting resistance, and, consequently, it is not possible to predict changes in loads on the working body of milling machines during its operation with worn cutting elements.Materials and methods. The experimental studies to determine the cutting resistance force that occurs during the milling of asphalt concrete with a maximum mineral aggregate size of 16 mm. used for the top layer of the coating and for roads with normal traffic conditions (A16vn), depending on the thickness of the chip being cut and the degree (percentage) of wear of the cutting element were carried out. To conduct the study, a pendulum stand, which is most suitable for studying the interaction of a single cutting element of a road milling cutter with asphalt concrete, was used.Results. As a result of experimental studies, it was possible to obtain the data allowing a reasonable approach to the choice of the interval of replacement of cutting elements during the operation of milling equipment, which, in future, will lead to an increase in the productivity of equipment and its service life. The achieved results make it possible to adjust previously obtained mathematical models and calculation methods of milling machines, taking into account the degree (percentage) of wear of cutting elements.Discussion and conclusions. The conducted studies make possible to determine the dependence of the cutting strength on the percentage of wear of the cutting element and the thickness of the chip being cut. At the same time, it can be concluded that in practice it is necessary to set additional safety margins when designing elements of a milling machine, taking into account the wear of the cutting element.

Randomized in situ evaluation of surface polishing protocols on the caries-protective effect of resin Infiltrant

The aim of this placebo-controlled randomized in situ study was to evaluate the effect of different surface polishing protocols on enamel roughness, bacterial adhesion and caries-protective effect of a resin infiltrant. Seventy-five bovine enamel samples having artificial caries lesions were treated with a resinous infiltrant and afterwards randomly dividided into five polishing protocols: aluminum oxide flexible disks (Al2O3-Disks), silicon carbide tips (SIC-Tips), silicon carbide brush (SIC-Brush), silicon carbide polyester strips (SIC-Strips) or no polishing [negative control (NC)]. Average surface roughness (Ra) was assessed by profilometry. Samples were mounted in palatal appliances under a mesh for biofilm accumulation. Fifteen volunteers wore the intraoral appliances (14-days) and cariogenic challenge was triggered by sucrose solutions. Biofilm formed was collected for microbiological analysis of caries-related bacteria (Streptococcus mutans, Lactobacillus acidophilus) and demineralization was assessed by cross-sectional microhardness. Mean Knoop hardness numbers (Kg/mm2) were plotted over lesion depth (µm) and area under the lesion curve was subtracted from sound enamel to determine demineralization (ΔS, Kg/mm2xµm). Data were analyzed by ANOVA and post-hoc comparisons (α = 0.05). NC resulted in significantly higher Ra means than Al2O3-Disks and SIC-Strips. Bacterial counts were not significantly different between the groups (p > 0.05). Regards ΔS means, however none of the groups were significantly different to NC (6983.3 kg/mm2xµm /CI 4246.1–9720.5, p > 0.05). Conclusions: Polishing protocols (Al2O3-Disks, SIC-Strips) significantly decreseased roughness of infiltrated-enamel, however none of the polishing protocols could signicantly decrease bacterial counts nor resulted in significant less demineralization.

Performance evaluation and failure analysis of conical picks used in a Botswana (Ngwato) mine

A coal mine in the central district of Botswana is experiencing premature failure of conical picks which mine 150–350 tons of coal/ pick rather than 400 tons/pick specification. This has adverse implications on business productivity and profitability due to the need to replace the picks with new ones. This study employed physical observation of mining operation; macroscopic and microscopic examinations; weight loss analysis; micro-hardness, and fractography analyses of one hundred and ninety-three (193) worn-out and five (5) new picks to investigate root causes of its failure and failure mechanisms with a view to identifying mitigation measures to avoid recurrent failure. It was observed that the picks situated at the extreme right and left ends of the cutter drum failed most frequently. Common modes of failure discovered for Botswana coal mine picks include one-sided wear of the pick body, pull-out of pick’s carbide tip, slimming steel body and even wear of carbide tip, and carbide tip deformation. Furthermore, cracking and crushing of tungsten carbide (WC) grains, cavity formation and pitting, coal intermixing, abrasion wear, long and deep cracks, rock channel formation, and corrosive degradation were identified as the failure mechanisms. Recommended mitigation measures to avoid repeated failures include the use of structurally stable materials at elevated temperature and characterised with improved hardness, toughness and wear resistance for pick manufacturing; exploring manufacturing technology that imparts improved bonding in the constituent materials without degrading material properties; redesigning of pick’s flange; and inspection of pick’s free rotation of the pick before starting any shift.

Analysis of CNC Turning Process of AA6082-T6 using Ansys Software

In this new technological world, CNC and manual turning operations engage in a significant role in different types of designing and manufacturing industries. Before initiating the manufacturing processes, analysis is a crucial part of the manufacturing process. This study involves modelling and analysis of the CNC machining process of a cylindrical AA6082-T6 workpiece with a Tungsten Carbide tip tool. A 3D model is first modelled on CATIA V5 and the analysis is then carried on in Ansys R19.2’s explicit module. The experimental and analytical results are carried out to justify the work. The cutting parameters used in CNC machining are Spindle rotational speed, feed rate, and depth of cut. The Normal Stress’s percentage error value varied too much compared to Shear stress and Shear Strain. This shows that the aluminium is suitable for the machining processes and can also be used more efficiently.

FIELD INVESTIGATION AND ASSESSMENT ON THE WEAR OF ASPHALT PAVEMENT MILLING MACHINE PICKS

Deteriorated asphalt pavement material is recycled applying proved technologies based on scientific principles and practical experience. The asphalt pavement layer during rehabilitation process is loosened by a mobile transport machine fracturing into the required material grading and called Reclaimed Asphalt Pavement (RAP). RAP is extracted while cutting asphalt chip in required depth at optimal speed by mean of changeable picks installed in a toolholder of milling machine rotating drum. During interaction with the asphalt pavement to be demolished, the wear of picks appears, and the dimensions of their elements decrease. Methodology and results of a field experimental research allowed statistically to determine and evaluate the wear dynamics of picks from 2 manufacturers are provided in this paper. The results provide that length of pick, diameter of carbide tip and diameter of steel body of picks from these manufacturers were decreasing proportionally to milled asphalt pavement surface. Applying the Fisher’s criterion it was found that the variances of the reduction of these geometrical parameters are the same and they satisfy the normal distribution according to the Kolmogorov’s criterion. All values of Student’s criterion calculated statistics were higher than the critical values, which indicated that the wear intensiveness of the picks of the 2 manufacturers differed significantly. These data can be used to select suitable picks for the milling machine according to their wear intensity.

Analysis of cutting force, feed force and surface roughness of Cu-Al-Mn shape memory alloys under CNC turning

The present investigation into the CNC turning of Cu-Al-Mn SMAs was conducted using a tungsten carbide tip tool as a cutting tool material to determine the effect of machining factors, such as spindle speed, feed rate, and depth of cut, on the response factors such as cutting force (Fc), feed force (Ff), and surface roughness (Ra). Taguchi's L9 orthogonal array (OA) was used to plan the experiment. During the turning operation, the cutting force and feed force values were noted using a tool dynamometer attachment. From ANOVA, it was noticed that cutting speed and depth of cut were the important factors affecting the Fc, Ff, and Ra, followed by feed rate, which was less significant. From the experimental results, it was identified that with an increase in cutting speed at a particular feed rate and depth of cut, the formation of long thin chips and the number of chip curls rises. The C-type of chip was observed at same cutting conditions. The Ra was evaluated using a Mitutoyo equipment to study the effectiveness of machining operations, and it plays a significant role in predicting product quality as well. For a thorough investigation, chip morphology was examined using SEM analysis.

An Improved Procedure for the Quality Control of Sintered Carbide Tips for Mining Applications, Based on Quantitative Image Analysis of the Microstructure.

Conical picks are tools that treat surfaces used in mining. Due to a wide variety of such tools, they need to characterise in diversified geometrical and material parameters, as well as durability. For the mining sector, evaluation of the conical picks is performed in order to verify their agreement with the manufacturer’s declaration, as well as with the requirements of the user. One of the whole research procedure elements is a qualitative and quantitative analysis of a pick tip made of sintered carbide (tungsten carbide–cobalt; WC-Co). It is currently carried out when the recipient is accepting such picks or when a complaint is made. In this case, it is important to propose such a research and control procedure that will make it possible to determine the quality of the applied material for pick tips in a straightforward, repeatable, and objective way. This article presents the results of investigations made on tips coming from four different types of conical picks. The tips’ hardness and density were measured, as well as WC grains which were characterised using two kinds of measurements (automated linear-intercept method and semi-automated planimetric methods). The measurements of the WC grains were conducted on microstructure images recorded using a light microscope. The performed investigations made it possible to compare tips and refer the results to those of other scientists’ studies. The final effect is a proposal of a specialised procedure examining picks, especially their tips, made of sintered carbides. This is important for the evaluation of the tips’ quality in light of the requirements of the relevant norms and the needs of the users from the mining and extractive sectors.

Modelling the Influence of Slide Burnishing Parameters on the Surface Roughness of Shafts Made of 42CrMo4 Heat-Treatable Steel.

This article presents the results of tests aimed at determining the effect of slide burnishing parameters on the surface roughness of shafts made of 42CrMo4 heat-treatable steel. The burnishing process was carried out using tools with polycrystalline diamond and cemented carbide tips. Before burnishing, the samples were turned on a turning lathe to produce samples with an average surface roughness Ra = 2.6 µm. The investigations were carried out according to three-leveled Hartley’s poly selective quasi D (PS/DS-P: Ha3) plan, which enables a regression equation in the form of a second-order polynomial to be defined. Artificial neural network models were also used to predict the roughness of the surface of the shafts after slide burnishing. The input parameters of the process that were taken into account included the values of pressure, burnishing speed and feed rate. Overall, the burnishing process examined leads to a reduction in the value of the surface roughness described by the Ra parameter. The artificial neural networks with the best regression statistics predicted an average surface roughness of the shafts with R2 = 0.987. The lowest root-mean-square error and mean absolute error were obtained with all the network structures analysed that were trained with the quasi Newton algorithm.

Comparative analysis of experimental methods to assess the resistance of milling road asphalt concrete

The paper is devoted to the comparative analysis of experimental evaluation of cutting resistance of road asphalt concrete to cutting elements with cylindrical carbide tips, which are widely used in rotors of road milling machines. The paper shows the comparison of the results obtained from the study of cutting of typical asphalt concrete with a single cutter on a pendulum stand and on a stand with a mechanical low-speed drive of the cutting element. The advantages and disadvantages of both methods are determined and provided in the paper. The conclusions obtained allow us to recommend reasonably the methods of research of strength indicators of asphalt concrete from the point of view of cutting resistance to cutting with working bodies of road machinery.

Инструментальные материалы для токарной обработки специализированных нержавеющих сталей

The article considers the issues of increasing the tool durability when turning specialized hard-to-work corrosion-resistant stainless steels 09Kh17N7Yu, 12Kh18N10T and 13Kh15N5AM3 with standard replaceable carbide tip. To develop recommendations for reducing tool consumption, a number of experimental and simulation studies was performed. The simulation was performed in the Deform software for three parameters: temperature, stress, and strain. The simulation results are compared with the operational parameters (wear of the tool material). Simulation was performed for ten different coatings on a hard-alloy substrate of the VK8 brand. The tool hard alloy VK8 is used as the base tool material, the other tool materials differ in the architecture (design, composition, structure and coating method) of the coatings applied to the VK8 substrate. The techniques of selecting the most rational tool materials are developed. The results obtained by simulation are verified experimentally. A good agreement between the results of simulation and experimental research has been achieved.

Prediction of surface roughness in turning of duplex stainless steel (DSS) using response surface methodology (RSM) and artificial neural network (ANN)

In this present study, an experimental investigation has been done to predict surface roughness by taking into consideration of the following parameters: cutting speed, rate of feed, cutting depth and nose radius in the hard turning of Duplex 2205 (ASTM A276) round bar material utilizing carbide tip tool material. Machining of duplex stainless Steel is considered as an inefficient machinable material, low removal rate and requires more exertion to machine the item. For experimental purposes, the 4-factor and 5-level design matrix is structured using the Design-Expert software. The statistical method is used to analyze the variance using ANOVA technique to examine the unique performance character.The statistical method is employed to analysis of variance (ANOVA) in order to examine the performance uniqueness. A second-order mathematical model is created according to the Design of Experiments (DoE) of Response Surface Methodology (RSM) to anticipate surface roughness. In view of cutting test, the cutting speed is the parameter which has the greatest impact on the machining activity. The nose radius is a minor parameter that has a less impact on machining activity. For the best possible results, the cutting parameters leading to surface roughness, the Artificial Neural Network (ANN) model is trained and tested using MAT Lab. For this condition, the ANN suggests the utmost least predicted value of surface roughness. The results of the tests confirming the expected values proved to be in perfect agreement with the experimental values. Finally, efficiency of three different ANN transfer function were compared to choose the best predicted values. The Log-sigmoid is the most suitable transfer function that provides minimum surface roughness.

Analysis of cutting conditions in the process of cross-cutting wood by circular saws

An analysis was conducted of the effects of cutting conditions in the cross-cutting of wood using circular saws. Gradual wear of the saw blade cutting wedges impacted the entire cutting process. Two different types of circular saw blades were used. One blade type featured sintered carbide tips and 54 saw blade teeth, whereas the other had high-speed steel with 56 teeth; both saw-blades were 600 mm in diameter with a rake angle of 20°. The two wood species were spruce (Picea abies) and beech (Fagus sylvatica). During sawing, the timber was fed at a velocity of vf = 6 and 12 m·min-1. The cutting speed (vc) was set at 60 m·s-1, 70 m·s-1 and 80 m·s-1. The saw blades were coated with three types of PVD coatings. The least energy intensive saw blade was a sintered carbide-free saw blade with a coating (AlTiN) at a displacement speed of 12 m·min-1 and cutting speed of 60 m·s-1 with a power of 1310,63 W. Any change of a saw blade considerably affected torque for all the wood species, so a particular type of saw blade will always have an impact on torque. Other parameters distinctively and individually influenced the process of wood sawing.

Comparative study and modelling of machinability characteristics of single and double tempered AISI H13 steel during hard part finish turning using brazed tungsten carbide tip

The machinability of a material is highly influenced by the surface quality and material removal rate during the machining process. In any machining process, it is cardinal to have a thorough study about how the process parameters affect the machining quality. AISI H13 tool steel is a widely used as a die material at elevated temperatures in industries. A better surface quality of this dies will definitely be efficacious in ensuring product quality and smooth production lines. Thus, this study focuses on the comparative study of the effects of cutting speed, feed rate and depth of cut on surface roughness and material removal rate (MRR) on the hard part finish turning of single tempered and double tempered AISI H13 steel. Initially, annealed workpiece was hardened and tempered at a specified temperature. The machining was done using brazed uncoated tungsten carbide tip as the cutting tool material. Taguchi’s L-25 orthogonal array was implemented for conducting the experiment with the aim of achieving minimal surface roughness (Ra) and maximize the material removal rate (MRR) by determining the optimal combination of input parameter for the desired response. To study the significant effect of the process parameters and the individual percentages contribution on the response parameters, analysis of variance (ANOVA) was performed. Thus, the effect of two type of heat treatment on the machinability characteristics of the material was studied. Also, artificial neural network (ANN) models were developed for all the response parameters i.e. surface roughness and MRR which depicted propitious predicting potential for determining the required responses at any combination of cutting speed, feed rate and depth of cut.

A study and modeling of cutting forces in dry turning of heat treated AISI H13 tool steel with brazed tungsten carbide tip

The machining efficiency and tool life is greatly influenced by the cutting forces generated. As a machining operation is a complex process, it is important to have a thorough idea about the parameters affecting the machining quality. The fine machining quality of the dies produced will be efficacious in the production lines and will also ensure the quality of the product being produced. One such material widely used as hot working dies and casting dies is AISI H13 steel. Thus, this study focuses on investigation of the effects of cutting speed, feed rate and depth of cut on the cutting force components produced during the hard finish turning of heat treated AISI H13 steel using uncoated brazed tungsten carbide tip as the cutting tool material. Initially, annealed H13 steel was hardened and tempered (54 HRC) at specified temperature. Taguchi’s L-25 orthogonal array comprising of 3 factors and 5 levels of each was employed for minimizing the cutting forces generated during machining, with the help of signal to noise ratio evaluation. Analysis of variance (ANOVA) study showed that the effect of feed rate and depth of cut on the cutting forces generated are statistically significant in comparison to cutting speed. Additionally, artificial neural network (ANN) models were developed which depicted promising predicting capabilities for determining the cutting forces at any cutting conditions

Failure Analysis of a Fractured Saw Blade Carbide Tip

A mechanical and metallurgical analysis was performed on a 10-inch circular saw blade involved in a table saw incident in which a fragment of a carbide tip from the saw blade struck an individual in the eye. This individual claimed the saw blade had never previously been used. Examination of the carbide tip fragment revealed yellow paint on the fracture surface indicating a preexisting crack was present during the saw blade assembly process. Chemical analyses indicated that the residue found on the saw blade was consistent with chipboard (OSB). Exemplar testing found similar wear patterns between the subject saw blade and an exemplar used to cut chipboard. Stress analysis of a saw blade tip indicated the stresses generated due to blade rotation alone would not be sufficient to cause fracture or separation of a carbide tip even if the carbide tip contained a preexisting crack. It was concluded that the carbide tip likely fractured and separated from the saw blade due to a preexisting crack in the carbide tip which grew from impact with a hard object during cutting operation.