Cemented Carbide Ball Research Articles

Friction, wear, and corrosion behavior of nitrocarburized HT250 gray cast iron

This study employed friction and wear experiments on nitrocarburized HT250 gray cast iron, utilizing GCr15 cemented carbide balls as the friction pair, to investigate the friction behavior and wear mechanism of the compound layer, diffusion layer, and matrix. The findings indicate that the diffusion layer exhibits the highest wear resistance, followed by the compound layer, while the matrix shows the lowest wear resistance. At lower loads, the wear form of the compound layer is characterized by minor flaking wear, the diffusion layer exhibits minor flaking and abrasive wear, and the matrix displays minor adhesive wear accompanied by abrasive wear. With increasing loads, the wear form of the compound layer transitions to flaking and abrasive wear, the diffusion layer shows fatigue flaking wear, and the matrix demonstrates severe adhesive wear, fatigue flaking wear, and abrasive wear. Electrochemical impedance spectroscopy and potentiodynamic polarization were employed to study the corrosion behavior of the compound layer, diffusion layer, and matrix in a 3.5 wt% NaCl solution. The results indicate a 27.7 % decrease in the corrosion current density of the compound layer compared to the matrix, with the diffusion layer exhibiting a corrosion current density two orders of magnitude lower than both the matrix and compound layer. In electrochemical impedance spectroscopy, the diffusion layer shows the highest impedance modulus, largest phase angle amplitude, and circular arc radius. It shows that the corrosion resistance of HT250 gray cast iron is improved after nitrocarburizing, especially the diffusion layer.

Evaluating the Tribological Behaviour in Cutting Operations Using a Modified Ball-on-Disc Open Tribotester

Predicting the tribological behaviour in the secondary shear zone in the metal-cutting processes is considered a significant challenge in contemporary research. This work investigated the frictional performance in the secondary shear zone of a planing process using a modified ball-on-disc open tribometer. The values of the coefficient of friction (COF) were tracked between an AISI4140 + QT disc (chip) and a cemented carbide ball (cutting tool) coated with TiAlN under three contact pressures of 0.5, 1, and 2 GPa at a range of sliding speeds starting from 0.2 m/s to 1.6 m/s. The tests were conducted under both dry and lubricated conditions using three commercial cutting fluids of CSF 35 straight oil, Vasco 6000, and Zubora 67H emulsions. Also, the MWFs were tested for their rheological properties and wettability. The tribometer results validated the same COF trend as that in the actual metal-cutting experiments, particularly at 0.5 and 1 GPa in dry conditions. Moreover, Zubora 67H emulsion is proven to be the optimal choice due to it reducing the COF between the rubbing contacts by up to 78%. Furthermore, it showed the lowest contact angle and viscosity index, revealing its ability to easily penetrate, especially at higher temperatures, within the secondary cutting zone.

Comparative Investigation on Fretting Wear of Nickel-Based Superalloy Surfaces Induced by Mechanical Polishing and Grinding

The purpose of this study is to comparatively investigate the wear behavior of nickel-based superalloy surfaces induced by mechanical polishing and grinding using the contact fretting against YG6 cemented carbide balls. Experimental results indicate that the friction coefficient and wear volume of the ground surface of nickel-based superalloy are smaller by 7.3% and by 18% on average, respectively, than those of the polished one. Furthermore, the high fretting wear loss of polished nickel-based superalloy can be attributed to the wear recirculation process composed of the plastic deformation, oxidization wear, surface and subsurface micro crack, which eventually leads to the significant material peeling and fatigue delamination. However, the ground nickel-based superalloy presents mainly the abrasive wear and excellent fretting wear-resistance due to the high hardness induced by grinding and the completely continuous compacted debris layer with few cracks instead of the ground surface to contact with the counterpart ball. Obtained results are beneficial for deepening the understanding of degradation mechanism during fretting of the nickel-based superalloy surfaces prepared by mechanical grinding and polishing.

Damage Accumulation Phenomena in Multilayer (TiAlCrSiY)N/(TiAlCr)N, Monolayer (TiAlCrSiY)N Coatings and Silicon upon Deformation by Cyclic Nanoindentation.

The micromechanism of the low-cycle fatigue of mono- and multilayer PVD coatings on cutting tools was investigated. Multilayer nanolaminate (TiAlCrSiY)N/(TiAlCr)N and monolayer (TiAlCrSiY)N PVD coatings were deposited on the cemented carbide ball nose end mills. Low-cycle fatigue resistance was studied using the cyclic nanoindentation technique. The obtained results were compared with the behaviour of the polycrystalline silicon reference sample. The fractal analysis of time-resolved curves for indenter penetration depth demonstrated regularities of damage accumulation in the coatings at the early stage of wear. The difference in low-cycle fatigue of the brittle silicon and nitride wear-resistant coatings is shown. It is demonstrated that when distinguished from the single layer (TiAlCrSiY)N coating, the nucleation and growth of microcracks in the multilayer (TiAlCrSiY)N/(TiAlCr)N coating is accompanied by acts of microplastic deformation providing a higher fracture toughness of the multilayer nanolaminate (TiAlCrSiY)N/(TiAlCr)N.

Effect of tungsten carbide content on the tribological behavior of TiB2–TiC-based cermets

TiB2–TiC-based cermets are expected to replace cemented carbide in the cutting and finishing of ferrous alloys, steel, aluminum, copper, and other nonferrous metals owing to their excellent wear resistance and cutting performance. In this study, the tribological behaviors and wear mechanisms of TiB2–TiC-based cermets with different WC contents were investigated by sliding the specimens against a cemented carbide ball. As the WC content of the TiB2–TiC-based cermets increased from 0 to 25 wt%, the wear rate and friction coefficient first increased and then decreased. Cyclical changes were observed in fatigue, adhesive, and abrasive wear. Explanatory mechanisms were proposed for these phenomena. This is the first comprehensive study on the effect of the WC content on the tribological properties of these important composites.

Tribological performance of DLC-coated ceramics against cemented carbide under dry sliding conditions

In order to improve the tribological behavior of Si3N4/TiC ceramics, DLC coating was fabricated on the ceramic surface through magnetron sputtering technology. The surface and cross-section micrographs, the adhesion between coating and substrate, the surface roughness and microhardness of the DLC-coated ceramics were investigated. Reciprocating friction tests sliding against cemented carbide ball were conducted under dry sliding conditions. The test results indicated that the DLC coating possessed superior tribological performance, which was conductive to decreasing the friction coefficient and enhancing the wear resistance of ceramics. The primary mechanisms responsible for performance improvement of the DLC-coated ceramics were attributed to the combined effects of low shear stress, excellent adhesion with substrate, high microhardness and good surface roughness. It was believed that the DLC coating was efficient in improving the load-carrying capacity and expanding the application area of ceramic materials.

Tribological Behavior of Hafnium Diboride Based Material

Tribological behavior of hot pressed HfB2-5%TiSi2 composite was studied under reciprocative sliding condition using cemented tungsten carbide (WC-Co) ball as counter body. Coefficient of friction (COF) for HfB2 composite sample was obtained in the range of 0.43 to 0.63 at different loads. It was observed that enhancement of load from 5 to 15 N resulted in decrease of COF of HfB2. Specific wear rate of HfB2 composite was evaluated in the order of 10–6 mm3/N.m. Microstructures of wear scar revealed that tribochemical layer was formed on the worn surface of HfB2 (flat).

Nano-Crystallization of Steel Surface by Slide-Burnishing

Slide-burnishing is one of the most powerful processes for microstructural evolution. Here slide-burnishing was performed by a cemented carbide ball loaded and fed on the flat surface of a rotating disk specimen of carbon steel using a lathe machine. This process provides many advantages: burnishing reduces the surface roughness, increases the surface hardness due to grain refinement, improves the wear resistance, and requires no special equipment. Transmission electron microscopy (TEM) observation revealed that nano-crystalline structures in the 10–300 nm grain size range were formed at the burnished sub-surface layer and that grain size increased approximately linearly with depth below the surface due to the strain gradient. High rotation speed in the burnishing process prompted further grain refinement, as evidenced by ultrafine and equiaxed grains in the 10 nm size range at the top surface layer of the specimen burnished at the highest rotational speed. Burnishing increased the indentation hardness of the nano-crystalline layer by a factor of 3.5. The expected linear relationship between hardness and inverse square root of grain size was identified.

Productivity and Superficial Quality of an Aspherical Die Using CAD/CAM

Nowadays, it is hard to imagine modern industry without the manufacturing and design software aided by computer, known as CAD/CAM, once the search for excellence in complex geometry parts, reduced time, quality assurance and interchangeability is increasing. Within this quest, the CAD/CAM platform has become a significant factor in manufacturing, especially on complex surfaces parts, mainly because of superficial quality, reliability and product competitiveness. Defined as surface within one or more non-flat surfaces or non-square, usually represented by parametric models, the freeform surfaces are very complex, requiring the control of three or more axes simultaneously, making the CAM tool indispensable. Tests were carried out by milling of aspherical cavities, on VP100 steel samples, with cemented carbide ball nose inserts with TiAlN coating. Two cutting strategies – zig-zag and spiral – and two finishing (CAM) strategies – parallel plans and Z level – were also investigated. Final Surface quality, tool productivity and tool wear were related to machining time, surface roughness (Ra, Rz, Rku and Rsk) and tool wear (VBmax). Results showed that the chosen strategy (tool path) it is the main factor to productivity. Keywords: CAD/CAM; Superficial Quality; Milling; Finishing

Friction and Wear Behavior of AlTiN-Coated Carbide Balls Against SKD11 Hardened Steel at Elevated Temperatures

In this study, AlTiN coatings were deposited on YT14 cemented carbide balls by arc ion plating technique. The friction and wear behavior of the AlTiN-coated balls against SKD11 hardened steel was investigated by sliding tests using a ball-on-disk tribometer at various temperatures from 25 to 700 °C in air. The results showed that the friction and wear behavior was significantly influenced by the testing temperature. Obvious fluctuations were observed in the friction curves at elevated temperatures, which could be attributed to the formation and rupture of unstable Fe and Cr oxide layers. As the temperature increased from 25 to 500 °C, the wear rate of the coated balls increased from the scale of 10−21–10−20 m3/N m, and then decreased to 10−22 m3/N m as the temperature further increased to 700 °C. It was also found that the friction and wear behavior of the coated balls was directly dependent on the counterpart materials. As the temperature increased, the main wear mechanism of the coated balls changed from mild abrasive wear and adhesive wear to abrasive wear failure at 500 °C, and then transferred to adhesive wear and mild oxidation wear at 700 °C. For SKD11 hardened steel, the primary wear mechanism changed from delamination wear to abrasive wear and then transferred to plastic deformation and fatigue wear, accompanied by adhesive wear and tribo-oxidation wear.

Wear Resistance Improvement by Nanostructured Surface Layer Produced by Burnishing

Burnishing, which is one of the most powerful processes for microstructural evolution, was performed by a cemented carbide ball (6 mm in diameter) that was loaded and fed on the flat surface of a rotating disk specimen of carbon steel using a lathe machine. The effects of burnishing process parameters such as force and rotation speed on the surface roughness, microstructure and hardness were investigated. In addition the dry sliding wear properties of the burnished surface layers were studied using a ball-on-disk friction method. It was found that the burnished surface was much smoother than as-turned surface (before burnishing) owing to the plastic flow of the surface asperities through the rubbing motion of the burnishing ball. Nanostructure in the 30 - 50 nm grain size range was formed in the burnished sub-surface layer, and the hardness significantly increased due to the grain refinement. The nanocrystalline microstructure was observed at high burnishing forces and speeds owing to the high strain and strain rate of the friction-induced plastic deformation. Moreover the burnishing process reduced the specific wear rates by a factor of six. Thus we concluded that the wear resistance of carbon steel can be significantly improved by burnishing due to the smooth surface and nanostructured sub-surface layers.

Development and tribological properties of SiC fibre reinforced CrB2 composite

SiC fibre (SiCf) reinforced CrB2 composite was prepared by hot pressing at 1700 °C. The developed composite was characterized by microstructural characterization and mechanical property measurement. Friction and wear properties of the hot pressed CrB2 + 10%SiCf have been investigated under reciprocative sliding, using a counter body of cemented tungsten carbide (WC-Co) ball. Coefficient of friction and wear rate were established. Wear mechanism has been analysed by using optical microscopy, scanning electron microscopy-energy dispersive spectroscopy and optical profilometer techniques. Higher than 95% density was obtained by hot pressing SiCf reinforced CrB2 at 1700 °C. Fracture toughness of the developed composite was measured to be 5.4 MPa m1/2, which is 54% higher as compared to that of monolithic CrB2. The coefficient of friction (COF) was measured to be 0.33 at 20 N load and 10 Hz frequency. Specific wear rate of CrB2 + SiCf has been found to be about 10−7 mm3/N m. Tribochemical reaction is shown to be the dominant wear mechanism in the present system.

Tribological characteristics of conventionally sintered TiCN-WC-Ni/Co cermets against cemented carbide

Present research deals with the tribological behavior of TiCN-WC-Ni/Co cermets with or without TaC in unlubricated sliding at different loads (5–20N). Commercially available cemented carbide hard material was selected as counterbody to understand the potential of new generation cermets in severe conditions of sliding. Dense TiCN based cermets were processed via conventional sintering whose hardness and fracture toughness varied from 14 to 16GPa and 8.75–9.25MPam1/2, respectively. The size and fraction of adjacent ceramic phase in the microstructure influenced mechanical properties and wear behavior of the cermets. A variation of 79% in steady state coefficient of friction (COF) and 70% in wear rate is found with respect to composition and load. Hard oxide debris particles are responsible for higher COF at low load, whereas their compaction results in the tribolayer formation at high load. Material transfer from cemented carbide ball onto the cermet disc enhanced at high load due to increased contact temperature. The refined size and least fraction of adjacent ceramic phase are attributed for reduced wear in TaC added TiCN-WC-Ni/Co cermet.

Low temperature carburised austenitic stainless steel for metal-on-metal tribological contact

S-phase layers formed on biomedical grade austenitic stainless steels have demonstrated significantly enhanced in-vitro wear and corrosion behaviour. To date, most of these tribo-corrosion studies on S-phase treated alloys were conducted using a polycrystalline alumina or cemented tungsten carbide ball as the counterface material. Testing S-phase against S-phase is both scientifically interesting and technologically important in view of their potential applications for the articulating surfaces of metal-on-metal joint prostheses. In this work, biomedical grade 316LVM discs together with AISI 316 balls were low temperature carburised. In-vitro corrosion-wear testing using an S-phase engineered ball against an S-phase engineered disc was performed. Such testing was also complemented with electrochemical impedance spectroscopy, potentiodynamic and cytotoxicity tests. The results have shown that the carburised 316LVM alloy was found to have good in-vitro cytocompatibility and an augmented corrosion and corrosion-wear resistance when compared with the untreated alloy.

Study on the high-speed cutting for plastic mould steel using Ball End Mill of AlTiN coating layers

This paper investigated into process characteristics of AlTiN coated layers for machining to the direction of upper and lower in plastic mould material (KP-4). It was used the cemented carbide ball endmill with the diameter of 8mm coated AlTiN layers (1 ~ 4) step by step using machining center. The material used in experiments is KP-4 that cut by three types of inclined angles; 15°, 30° and 45°. As estimated mechanical properties of AlTiN coated layers, it was shown the most result in the condition of three layered coating that the coating that the coating depth, the hardness of the coated layer. The surface roughness of the coated layer was 13 µm, Hv 3027.3 and 0.042 µm, respectively. The cutting component was better at the condition of upper direction than that of lower direction in all experimental conditions, and indicated to be less which the bigger angle of the material increase the effective diameter of the tool. DOI: http://dx.doi.org/10.5755/j01.mech.22.4.16157

Densification and ablation behavior of ZrB2 ceramic with SiC and/or Fe additives fabricated at 1600 and 1800 °C

The effects of Fe and SiC additions on the densification, microstructure, and ablation properties of ZrB2-based ceramics were investigated in this study. The sample powders were conventionally mixed by cemented carbide ball then sintered by spark plasma sintering. The ablation rates and behavior of the ceramics were investigated under an oxyacetylene torch environment at about 3000°C. A sample with high relative density (96.3%), high flexural strength (415.6MPa), and low linear ablation rate (−0.4µm/s) was obtained via SPS at 1600°C. Adding 4vol% Fe was more beneficial to the density of ZrB2 sintered at 1600°C as compared to ZrB2 sintered at 1800°C. The ablation behavior and rates were similar among samples sintered at 1600°C and 1800°C.

Investigation of the Si–B–C–N coatings deposited by magnetron sputtering of SiBC targets

Amorphous Si–B–C–(N) coatings are fabricated by magnetron sputtering of sintered Si–B–C targets. The coating structure is investigated using X-ray diffraction, scanning and transmission electron microscopy, scanning probe microscopy, glow-discharge optical emission spectroscopy, and Raman spectroscopy. Mechanical and tribological properties of coatings are determined using nanoindentation, scratch testing, and pin-on-disc testing. The oxidation resistance of coatings is investigated in a temperature range of 1200–1600°C. It is established that coatings of the optimal composition possess hardness of 20 GPa, elasticity modulus of 210 GPa, elastic recovery of 53%, friction coefficient of 0.6 against cemented carbide ball, and oxidation resistance above 1200°C due to the formation of the SiO2-based protective film on their surface. Coatings deposited by sputtering the target of the Si70B25C composition in Ar + 15%N2 medium showed oxidation resistance both under long-term heating at t = 1200°C for 12 h and short-term heating at temperatures of 1400, 1500, and 1600°C.

Investigation of the Si–B–C–N Thin Coatings Deposited Using Magnetron Sputtering of SiBC Targets

Amorphous thin-film Si–B–C–(N) coatings are fabricated by magnetron sputtering of sintered Si–B–C targets. The coating structure is investigated using X-ray phase analysis, scanning and transmission electron microscopy, scanning probe microscopy, glow-discharge optical emission spectroscopy, and Raman spectroscopy. Mechanical and tribological properties of coatings are determined using nanoindentation, scratch testing, and pin-on-disc testing. The oxidation resistance of coatings is investigated in a temperature range of 1200–1600 °C. It is established that coatings of the optimal composition possess hardness of 20 GPa, elasticity modulus of 210 GPa, elastic recovery of 53 %, friction coefficient of 0,6 against cemented carbide ball, and oxidation resistance above 1200 °C due to the formation of the SiO2-based protective film on their surface. Coatings deposited by sputtering the target of the Si70B25C composition in Ar + 15%N2 medium showed oxidation resistance both under long-term heating at t = 1200 °C for 12 h and short-term heating at temperatures of 1400, 1500, and 1600 °C.

Tribological properties of boron carbide in sliding against WC ball

Friction and wear properties of the hot pressed boron carbide have been investigated at different loads and frequencies under reciprocative sliding, using a counter body of cemented tungsten carbide (WC–Co) ball. Coefficient of friction, wear volume and wear rate were evaluated. Wear mechanism has been analysed by using optical microscopy, SEM-EDS and stylus profilometer techniques. Low coefficient of friction (COF) was measured as 0.15 at 10N load and 10Hz frequency. Load enhancement from 3 to 10N at 10Hz frequency led to a reduction of COF from 0.20 to 0.15. Specific wear rate of boron carbide has been evaluated in the order of 10−6mm3/Nm. Both abrasive and tribo-chemical reaction wear mechanisms are observed on the worn surface of boron carbide (flat).

Structure and Mechanical Properties of CrTiAlN/TiAlN Composite Coatings Deposited by Multi-Arc Ion Plating

CrTiAlN/TiAlN composite coatings were deposited on cemented carbide by using a home-made industrial scale multi-arc ion plating system. The samples were studied by X-ray diffraction, scanning electron microscopy (SEM), microhardness and ball-on-disk testing. The properties of the CrTiAlN/TiAlN coatings were significantly influenced by the microstructure and the deposition time ratio of TiAlN over CrTiAlN layers. With the increase of deposition time ratio, the microhardness of CrTiAlN/TiAlN increased from 28.6 GPa to 37.5 GPa, much higher than that of CrTiAlN coatings. The friction coefficients of the CrTiAlN/TiAlN coatings were higher than those of CrTiAlN coatings against a cemented carbide ball. The microhardness of the CrTiAlN/TiAlN coatings was changed after annealing at 800°C, and the friction coefficients of the annealed coatings were increased against the cemented carbide ball.