Papers by Keyword: Abrasive Wear

Abstract: A comprehensive study of the abrasive effects of lunar regolith is essential for mitigating damage to mechanical components during lunar missions. This research focuses on preparing lunar mare (LX-M100) and highland (LX-TH100) simulants with different particle size fractions to develop a tribological model for further investigation of their frictional properties. Fine and coarse simulants were separated using a digital electromagnetic sieve shaker, yielding five particle size fractions for each type. The sieving process revealed discrepancies between actual particle sizes and supplier data, highlighting the need for uniform particle size to ensure consistent wear testing. Simulants with uniform particle sizes produced more reliable and controlled wear patterns, especially in tribological experiments involving rotating shafts and seals. To replicate lunar conditions, future experiments will employ a custom-built pin-on-disc tribo-test rig and sand-pot test rig to evaluate the wear performance of a stainless-steel shaft and polytetrafluoroethylene (PTFE) seal. This study advances understanding of the abrasive impact of lunar dust, contributing to the development of more durable materials for future lunar exploration.

Abstract: Composite materials are increasingly being used in several areas, especially in the automotive and aerospace industries, however, during regular operation their wear is one of the main causes of failure. Consequently, developing and researching new composite materials is essential to increase and improve service life. In addition, thixoforming is claimed to exhibit superior properties by reducing typical defects in casting like shrinkage and porosity. Therefore, the main objective of this study is to produce and analyze abrasion wear properties of the thixoformed aluminum matrix composite reinforced with NbC, obtained by the stir-casting method. Three different composites with 5 wt.%, 10 wt.%, and 15 wt.% of NbC were manufactured with the stir-casting method, compared with A380 alloy. The procedure involves an A380 aluminum alloy that was molten at 750 °C. In sequence, niobium carbide powder was added by mechanical stirring for 10 min; Mg was added to improve the wettability between the reinforcement and matrix. Chemical grain refinement by Al-5Ti-1B master alloy was used for non-dendritic feedstock production. Hence, the induction furnace was used for the thixoforming process, to achieve a mushy of 60 % solid fraction at 562 °C, determined by Differential Scanning Calorimetry (DSC) analysis. The holding time applied was 90s. Optical microscopy (OM) and scanning electron microscope (SEM) analyses allowed the microstructural characterization. Abrasive wear tests, according to the ASTM G65 standard, showed an improvement of the composites’ abrasion wear resistance after the thixoforming process, with a higher amount of NbC, potentially increasing the range of use of this technology and materials.

Abstract: With today's proliferation of various polymers, it is necessary to assess the feasibility and feasibility of replacing rubber with more modern materials. The purpose of the tests was to study the effect of abrasive wear, the effect of temperature on material properties, resistance to chipping and other types of wear. This will allow assessing the possibility of application in well conditions, as well as determining the magnitude of the effect of each type of wear on the product. We were faced with the task of testing new protectors in conditions close to full-scale ones. For this, a stand was designed, which allows you to reproduce the lateral load, add abrasive and corrosive agents that affect the wear of the product, ensure circulation of the model fluid, with the characteristics of the drilling fluid, as well as study the effect of elevated temperature on the change in material properties. Due to the fact that in a real well the protector is not under constant load, especially in the vertical sections of the wellbore, but can rotate on the pipe, a day on the test bench can be equivalent to months when the protector is in the well. Therefore, the tests carried out can predict the wear of tread parts, as well as assess the reliability of the use of treads made of polymer materials.

Abstract: The drilling conditions are becoming more severe, which leads to the need to select new polymeric materials that can withstand heavy loads, provide a longer resource and are more resistant to high temperatures. To solve the problem, a set of laboratory tests on standard and specialized tribological equipment is proposed. The friction force, wear resistance under various conditions and according to various criteria, hardness at normal and elevated temperatures, thermal field during tests, change in the roughness of a steel counterbody as a result of tests are evaluated. Wear resistance is determined using a PBD-40 friction machine. Samples are cylindrical bodies with a diameter of (5.0 ± 0.5) mm, a height of 10.0 mm from the materials under study. The samples are fixed in the designed fixture. As a result of the tests, the average values ​​of the parameters for the investigated materials were determined, and the effects arising from friction were noted. The criteria for choosing a material have been formulated and the most suitable material for the tread has been selected.

Abstract: The results of the study of the cooling rate effect on the structure and properties of castings for parts of equipment made of complex alloyed manganese cast iron, which operate under conditions of abrasive and impact-abrasive wear, are presented. The properties and characteristics of microstructures of samples from the investigated cast iron composition for different cooling rates are given: relative and impact-abrasive wear resistance, hardness, volume fraction of the carbide phase, and the average size of carbides. It is shown that the cooling rate (as well as the chemical composition of cast iron) is a determining factor in the primary microstructure formation that affects the properties of castings.

Abstract: The introduction of small amounts of calcium stearate and molybdenum disulfide into polyurethane ureas based on a oligoether of polyoxytetramethylenediol with a molecular weight M~1000 does not lead to a significant change in the abrasive wear mechanism of the polymer material. The concentration dependence of the wear degree on the filler content has an extreme character, which is associated with the different direction of the filler effect on the cohesive and frictional properties of the studied material.

Abstract: We conducted comparative tests of the wear resistance of metals operating under abrasive conditions. Samples were cut from the working parts of mixer-pneumosuperchargers. The chemical composition and mechanical properties were determined. To compare samples under abrasive wear conditions, we designed and assembled a carousel installation. The principle of its operation is based on mixing the abrasive medium by the samples being studied with a given speed. Wear resistance was evaluated by weight loss by samples after several test cycles. To determine changes in the structure of the metal during abrasive wear, metallographic studies of the samples were carried out before and after the tests. It is shown that the best complex of service and mechanical properties is possessed by 110G13L steel.

Abstract: Natural fibers are widely used for reinforcement in polymer composite materials and proved to be effectively replacing synthetic fiber reinforced polymer composites to some extent in applications like domestic, automotive and lower end aerospace parts. The natural fiber reinforced composites are environment friendly, have high strength to weight ratio as well as specific strengths comparable with synthetic glass fiber reinforced composites. In the present work, hybrid epoxy composites were fabricated using calotropis procera and glass fibers as reinforcement by hand lay-up method. The fibre reinforcement in epoxy matrix was maintained at 20 wt%. In 20 wt% reinforcement of fibre, the content of calotropis procera and glass fibre were varied from 5, 10, 15 and 20 wt%. The dry sliding wear test as per ASTM G99 and three body abrasive wear test as per ASTM G65 were conducted to find the tribological properties by varying speed, load, distance and abrasive size. The hybrid composite having 5 wt% calotropis procera and 15 wt% glass fibre showed less wear loss in hybrid composites both in sliding wear test as well as in abrasive wear test which is comparable with 20 wt% glass fibre reinforced epoxy composite which marked very low wear loss. The SEM analysis was carried out to study the worn out surfaces of dry sliding wear test and three body abrasive wear test specimens.

Abstract: Friction happens everywhere. Abrasives generated in tribological process will result in secondary wear. Abrasive wear is a kind of rather common but harmful wear, which is the main reason for the damage of fifty-percent mechanical components by friction. Surface texturing is an effective method to improve the tribological and lubricating performance of tribo-pairs. In this paper, with different-size diamond particles added into the lubricant and a surface of the tribo-pairs textured by different parameters (diameter and depth) with femtosecond laser, the relationship between the surface texture and the abrasive wear was researched, and the influence of the texture on the abrasive wear was analyzed. The friction experiments were carried out on UMT3. The microstructures were tested and analyzed by SEM, microscope and White Light Interferometer respectively. The experimental results showed that the size of the surface texture, compared with that of abrasives, is the main factor which determines the friction coefficient. As the size of the surface texture is much bigger than that of the abrasives, the texture can accommodate the abrasives efficiently, and thus the friction coefficient is reduced efficiently.

Abstract: The paper presents the results of comparative tribological tests of diamond-like inserts. Methods of tribological tests on different tribological units are described. The results showed that a higher content of polycrystalline diamond in the insert improves the anti-wear and anti-friction properties of the composite.