Abrasive Wear Conditions Research Articles

Design of binder jet additive manufactured co-continuous ceramic-reinforced metal matrix composites

Ceramic-reinforced metal matrix composites (MMCs) display beneficial properties owing to their combination of ceramic and metal phases. However, the properties are highly dependent on the reinforcing phase composition, volume fraction and morphology. Continuous fiber or network reinforcement morphologies are difficult and expensive to manufacture, and the often-used discontinuous particle or whisker reinforcement morphologies result in less effective properties. Here, we demonstrate the formation of a co-continuous ceramic-reinforced metal matrix composite using solid-state processing. Binder jet additive manufacturing (BJAM) was used to print a nickel superalloy part followed by post-processing via reactive sintering to form a continuous carbide reinforcing phase at the particle boundaries. The kinetics of reinforcement formation are investigated in order to develop a relationship between reactive sintering time, temperature and powder composition on the reinforcing phase thickness and volume fraction. To evaluate performance, the wear resistance of the reinforced BJAM alloy 625 MMC was compared to unreinforced BJAM alloy 625, demonstrating a 64 % decrease in the specific wear rate under abrasive wear conditions.

The effect of powder addition manner and volume fraction of reinforcement on tribological behavior of Al7075/B4C surface composite produced by friction stir processing

Al7075/B4C surface composites were fabricated by friction stir processing using four passes. The B4C powders were added into the prepared grooves with 1 and 2 mm width at the surface of Al7075 alloy in two different manners. In the first one, the B4C powders were added prior to the four consecutive passes in one stage. In the second manner, the powders were added in two stages, prior to the first pass and following the second one. The microstructural evaluations showed that the increase in the volume fraction of reinforcement significantly reduced the matrix grain size. Meanwhile, the reinforcement had a more homogeneous and uniform distribution in the samples processed through four consecutive passes. The maximum hardness and wear resistance was achieved in the one-stage powder-added samples, containing higher volume fraction of the reinforcement. A direct relationship was observed between the wear resistance and the composite layer hardness. The wear mechanism in the Al7075 substrate and the non-reinforced friction stir processed sample was the delamination of unstable aluminum oxide tribolayer. However, in the composite samples, a mechanically mixed layer, containing aluminum, chromium, and iron mixed oxides was formed along with B4C on the worn surface. In the two-stage powder-added samples, containing lower amounts of reinforcement, the detachment of mechanically mixed layer resulted in three-body abrasive wear condition and high friction coefficient. However, the most stable mechanically mixed layer was formed on the surface of the one-stage powder-added sample containing higher amounts of B4C.

Wear Analysis of gun barrel drill blade in 1.0503 steel drilling process in Milpro HG12 oil environment with addition of ultra-dispersive copper particles and copper oxides

The paper presents construction solutions for guiding a single-sharp barrel drill blade during drilling deep holes, with an analysis of construction and technological problems for two ways of inserting the drill into the processed material in the first stage of drilling - using a pilot hole or guide sleeve.
 During the implementation of the technological process of deep drilling of holes with barrel drills using a vertical numerical milling machine FNE 40NC AVIA, the kinematics of the object-tool system (P-N) and other technological parameters affecting the execution of pilot holes in strictly defined technological operations were analyzed.
 The course of operational tests carried out using two types of cooling-lubricating agents - Milpro HG12 oil without and with the addition of ultra-dispersive copper particles and copper oxides (0.05 ÷ 0.6 µm), Panther GP-1 (PWPH PantherOil Poland) in a ratio of 1 to 100 is characterized.
 Based on the performed drilling of through holes in 1.0503 steel with EB80 drills with a diameter Dc = 8 mm, made of cemented carbide K15 (WC 94%, Co 6%), the course of wear of the barrel drill blade on the total drilling path Lw = 8000 mm for 112 was determined through holes and Kw geometric wear indicator of the drill bit.
 The obtained results of wear were compared with the results of tribological tests. with the use of cooling lubricants, under the conditions of friction involving 1.0503 steel with tungsten carbide, of chemical composition as K15. The material and technological conditions of abrasive wear of a particular friction pair are the same as for operational tests of the barrel drill blade wear at deep hole drilling.

Enhancement of wear resistance of mulcher teeth with the help of electrochemical coats

Influence of alloying additives in electrolyte and conditions of electrolysis on microhardness, adhesive strength and wear resistance of iron and cobalt coats have been investigated. Conditions of creating coats which make it possible to considerably enhance wear resistance of the mulcher teeth under the conditions of abrasive wear have been established. The process of creating wear resistant coats have been approved and recommended to introduction after the service life of the mulcher teeth sets have been extended.

Evaluation of the performance of sealing rubbers operated in conditions of abrasive wear and low temperatures

The studied materials based on the new rubbers of unique frost resistance -propylene oxide rubber (Tg = -74 °C) and Hydrin T6000 epichlorohydrin rubber are recommended to be used as static and dynamic sealing parts for the equipment operated in the North. This was based on the full-scale tests in cold climates (Republic of Sakha (Yakutia)) and evaluation of tribological characteristics (coefficient of friction) at negative temperatures. The standard techniques were used in assessing of the changes of the physical and mechanical, relaxation, and low-temperature characteristics of model rubbers after aging. A special testing unit and a method for conducting the tests were developed to estimate the coefficient of friction at low temperatures.

Determination of Wear, Friction Behavior and Characterization of Carbon Fiber Reinforced Epoxy Composites for Transport Applications

Abstract Thermoplastics are finding the place in the current industrial sector due to its load bearing capacities. In this research, With the aid of pin on disc test set up, adhesive and abrasive wear behavior of leaf spring materials 30% short carbon fiber reinforced epoxy (SF), 30% long carbon fiber reinforced epoxy (LF) as well as Unreinforced epoxy (UF) are evaluated for automobile applications. Under multi pass abrasive wear condition, the effect of fiber reinforcement on plastic energy of deformation, matrix crystallinity and clogging behavior were investigated. The transient friction of Leaf spring materials was carried out under the load condition of 19.62N and 28.43N. During the friction test, the effect of fiber length, fiber loading condition on the co-efficient of friction and its specific wear rate of the composite materials are also investigated. The increase in load during adhesive mode for all the materials, specific wear rate and wear volume of the test materials also increased. Furthermore, the fiber- matrix interface, fractured surfaces were observed thoroughly through Scanning Electron microscopic (SEM) morphology.

Wear Resistance of Plasma-Sprayed Coatings in Intensive Abrasive Wear Conditions

The abrasive wear resistance of plasma-sprayed oxide ceramic (Al2O3 and Cr2O3) and clad cermet ((Ti–Cr–C)–30% Ni and (TiC)–30% Ni) coatings was studied. The wear characteristics of the coatings such as wear rates, friction forces, friction coefficients, and wear groove depth determined with two methods were compared. The wear test methods included simulation of the friction process using loose abrasive particles and reciprocal ball-on-disk friction using a diamond indenter. The plasma-sprayed TiC-based coatings showed the lowest wear rate and can be applied to protect equipment parts subjected to intensive abrasive wear. The wear loss of the (Ti–Cr–C)–30% Ni and (TiC)–30% Ni coatings determined by friction against loose abrasive particles was 10–17 μm, while the wear loss of the oxide ceramic coatings was 20–42 μm, being 2–2.5 times higher on average.

Chopped Carbon Fiber Reinforced Polymer Composites : Effect of Nanoclay on Adhesive and Abrasive Wear Properties

The present work investigates the wear properties of nanoclay-modified carbon fiber reinforced polymer (CFRP) composites when sliding under adhesive and abrasive wear. The specimens were fabricated using epoxy resin, short carbon fiber, and nanoclay filler of 1.0wt%, 3.0wt%, and 5.0wt% content. The wear tests were conducted using pin-on-disc and abrasion resistance test rig for adhesive and abrasive wear condition, respectively. Operating parameters were fixed at 30N load, 300rpm speed and 10km distance for both tests. Pure CFRP composite exhibited lower wear performance compared to pure epoxy in both test conditions. However, with nanoclay incorporation, the wear properties of CFRP composite have improved up to 56% and 44% under adhesive and abrasive wear, respectively. Therefore, the composite reinforced polymer of carbon fiber and nanoclay filler in epoxy matrix provides a synergistic effect under adhesive and abrasive wear conditions. The experimental findings suggest that the CFRP composite has the potential for tribological components and application such as sliding-contact and rolling-contact bearings.

Feature extraction method of abrasive belt wear state for rail grinding

Abrasive belt has the advantages of high removal efficiency and high waste collection; furthermore, it does not easily damage the rail when applied in rail grinding. However, the poor wear consistency and short service life restrict its development in this field. It is important to explore the theory and technology of monitoring the abrasive belt wear condition to evaluate the means of improving the grinding performance of the belt. This article discusses the contact stress state between the belt and the rail surface. In addition, the study establishes the belt rail grinding force model during operation using the abrasive grain distribution function. The analysis of the force model proposes that the belt abrasion condition be monitored by using the force ratio parameter of the abrasive belt in the grinding process. The extraction method of the force ratio information is proposed in accordance with the grinding environment. The results of experiments successfully verified the validity of the method.

Use of Acoustic Emissions to detect change in contact mechanisms caused by tool wear in abrasive belt grinding process

Abrasive belt tools are widely used for finishing processes, where the abrasive grains on the belt tool serve as the cutting edge to remove materials. The interaction between abrasive grain and the material surface might result in three contact mechanisms, i.e. rubbing, ploughing and cutting, where their nature are not fully understood. On the other hand, the performance of a coated abrasive belt tool is highly affected by the grain wear. A single grain scratch test with different abrasive grain wear conditions is conducted to explore the three contact mechanisms. Through scratch experiments of prismatic Aluminium Oxide (A12O3) grain on Aluminium 6061 workpiece, Acoustic Emission (AE) frequency signatures that correspond to the three mechanisms are examined. Dominant frequencies and energy signatures occupied by the three contact mechanisms are analysed using Short-Time Fourier Transform (STFT). The energy content of the dominant frequency signatures revealed that the cutting mechanism is more predominant on belt tool with new grains, which gradually becomes less significant as the grain wears. A similar trend is also observed in ploughing and rubbing modes with respect to the wear flat level of the belt tool. The general conclusion suggests that the intensity of contact mechanisms changes according to the condition of the abrasive grain, i.e. tool wear, and can be correlated with AE sensor data.

Method of providing wear-resistance of the blades of paddle mixers.

The work is devoted to solution of the actual problem to increase the service life of blade mixers used in the foundry industry. The existing methods for ensuring wear resistance of mixing blades are described, their advantages and disadvantages are indicated. Based on the analysis of scientific publications a technical solution for applying protective coatings to the blades of the mixer using gas-thermal spraying has been proposed. The results of laboratory studies of the wear rate of gas-thermal coatings from various powder mixtures of the Ni-Cr-B-Si system under conditions of abrasive wear are presented. The results of operational tests of experimental products under conditions of corrosion and abrasive wear during the operation of a paddle mixer are given. The composition of the powder mixtur ensuring maximum wear resistance of the mixer blades was developed.

Corrosion properties of the deposited coatings of the system fe-15cr

Coating of machine parts and mechanisms operating in a corrosive environment is an important task of modern engineering. The surfacing of working surfaces by chromium steels has wide possibilities for the formation of corrosion-resistant coatings. The basis of most of these steels is the system Fe-Cr. For surfacing of corrosion-resistant coatings it is efficient to use economically alloyed flux-cored wire of the system Fe-15Cr. At the same time, the corrosion resistance of the deposited metal of such a system has not been studied. In connection with the above, the purpose of the work was to study the corrosion properties of the metal deposited by chromium flux-cored wire of the Fe-15Cr system. Tests for general corrosion were carried out in a salt fog chamber (SFC) at a temperature of 50±1 °C while spraying copper-acetic acid salt solution (neutral brine with the addition of dihydrated copper chloride (CuCl2 + 2H2O) and crystalline acetic acid) for 3 hours every 1 hour. The evaluation of the corrosion behavior in a salt fog chamber of the metal deposited by flux-cored wire PP-Kh15 was carried out in comparison with the metal deposited by standard wire Sv-20Kh13. It is established that the properties of the metal deposited by wire PP-Kh15 at the initial stage of corrosion behavior, estimated at the time until the first signs of corrosion appear, exceed the properties of the metal deposited by standard wire Sv-20Kh13 in 4.8 times, and for long-term corrosion resistance in 1.49 times. The lowalloyed flux-cored wire PP-Kh15 can be recommended for surfacing coatings on parts of equipment used in production, transportation and storage of oil operating in slightly aggressive environments under conditions of slight abrasive wear.

Исследование технологических параметров процесса получения чугунных отливок для работы в условиях износа

The paper provides a detailed description of the state of the issue, which concerns the relevance of improving the wear resistance of machine and mechanisms parts operating under conditions of intense abrasive and impact-abrasive wear

Wear behaviors of WC and TiC on co matrix composites under three-body impact abrasive wear condition

PurposeThe purpose of this paper is to investigate the tribological properties of the WC/TiC-Co substrate under different loading conditions under three impact abrasive wear conditions.Design/methodology/approachThe three body collisional wear behavior of Co alloy with WC and TiC at three impact energy was studied from 1 to 3 J. Meanwhile, the microstructure, hardness, phase transformation and wear behavior of these specimens were investigated by scanning electron microscopy, Rockwell hardness (HRV), EDS and impact wear tester. The resulting wear rate was quantified by electronic balance measurements under different pressures.FindingsThe specific wear rate increases with the increase of the nonlinearity of the impact energy and the increase in the content of WC or TiC. The effect of TiC on wear rate is greater than that of WC, but the hardness is smaller. The wear characteristics of the samples are mainly characterized by three kinds of behavior, such as cutting wear, abrasive wear and strain fatigue wear. The WC-Co with fewer TiC samples suffered heavier abrasive wear than the more TiC samples under both low and high impact energy and underwent fewer strain fatigue wears under high impact energy.Originality/valueThe experimental results show that the wear resistance of the Co alloy is improved effectively and the excellent impact wear performance is achieved. The results can be used in cutting tools such as coal mine cutting machines or other fields.

Study of the operating in conditions of abrasive wear deposited layer obtained with the use of new flux-cored wires

The effect of introduction of chromium with increased concentration as a reducing agent was studied at the manufacture of flux cored wire of the Fe – C – Si – Мn – Сr – Ni – Mo system. Metal welding deposition was carried out on the plates of St3 steel with the help of AN-26С flux with preliminary heating of the base metal to 250 – 300 °С. Flux cored wire of5 mmin diameter, made on a laboratory machine, was deposited on ASAW-1250 welding tractor in the following modes: current 420 –520 A, voltage 28 – 32 V, welding speed 7.2 – 9.0 m/h. After it the metal was cooled at room temperature. For manufacture of the samples, the corresponding powdery materials were used as fillers (charge): iron powder PZhV1 according to GOST (State Standards) 9849 – 86, FS 75 ferrosilicon powder according to GOST 1415 – 93, FKh900A high carbon ferrochrome powder according to GOST 4757 – 91, FMn 78(A) carbonaceous ferromanganese powder according to GOST 4755 – 91, PNK-1L5 nickel powder according to GOST 9722 – 97, FMo60 ferromolybdenum powder according to GOST 4759 – 91, FV50U 0.6 ferrovanadium powder according to GOST 27130 – 94, PC-1U cobalt powder according to GOST 9721 – 79 and tungsten powder PVN TU 48-19-72-92. It was determined that carbon, manganese, chromium, molybdenum, nickel and, to a small extent, vanadium, within the limits studied, simultaneously increase hardness of the deposited layer and decrease wear rate of the samples. It is shown that the low viscosity of the matrix does not allow tungsten carbides to be kept on the surface, as a result of which the wear is carried out not according to the uniform abrasion of the surface, but according to the scheme of spalling high-strength carbides particles from the matrix. As a result, new cracks are formed in the matrix, contributing to its additional wear. According to the results of the multifactor correlation analysis, dependences of hardness and wear resistance of the deposited layer on mass fraction of the elements included in the flux-cored wires of the Fe – C – Si – Мn – Сr – Ni – Mo system were determined. The obtained dependences can be used to predict hardness and wear resistance of the deposited layer with a change in the chemical composition of the weld metal.

COMBINED TECHNOLOGY OF ELECTRO-SPARK ALLOYING AND THERMAL DIFFUSION BORIDING OF STEEL

The process of thermal diffusion boriding is well known and used throughout the world. It has a number of unique properties, such as high hardness and wear resistance under abrasive wear conditions. Continuous boride layers have increased brittleness, which is related with the elastic properties of borides. In this work, we studied the features of the formation of surface layers onlow-carbon steels after electro-spark alloying, and not by continuous processing of the entire surface of the steel, but only sections and subsequent thermal diffusion boriding from powder medium. Such complex technology enables to form discrete regular and irregular layers, which have a number of advantages, in particular, reduced brittleness. The structure and phase composition of the combined coating growth kinetics of the diffusion layer during the thermal diffusion boriding, are investigated. The creation of the considered composite layers with FeB and Fe2B phases with reduced brittleness will significantly expand their area of application, for example, for working conditions with moderate impact loads.

Deposition of amorphous hardening coatings by electrospark treatment in a crystalline granule mixture

The article focuses on the preparation of amorphous coatings on the Steel 1035 surface by electric spark treat the coating composition control by changing the granule mixture composition was studied. EDS analysis showed that the coatings obtained contain W, Mo, Co and Ni in different ratios. The weight of granules having different compositions decreased by 11–16 wt.% in 6 hours of treatment as a result of electric erosion. The mass transfer coefficient varied from 33 to 54 %. X-ray diffraction analysis showed the predominance of the amorphous phase in the composition of layers deposited. Annealing of the coatings at 1150 °C led to amorphous phase crystallization into M23(C,B)6 type borocarbide and α-Fe. The coatings had an increased microhardness of 10–15 GPa, and their wear resistance under dry sliding wear conditions at 10 and 50 N loads was 3,3 and 1,6 times higher, respectively, than in Steel 1035. The highest values at both loads were shown by samples without nickel, while samples without tungsten featured the lowest values. The coatings had a friction coefficient within 0,27–0,31 that is lower than for Steel 1035 by 13–30 %. Wear resistance of the coatings under dry abrasive wear conditions at the 25 N load was 3 to 5 times higher as compared to uncoated Steel 1035. Samples without nickel demonstrated the best performance, while samples without cobalt had the worst indicators. Thus, it was shown that tungsten and cobalt increase wear resistance of iron-based amorphous alloys, while nickel and molybdenum tend to worsen their tribotechnical behavior.

The Structure and Properties of the Molybdenum-Doped WC–W2C Eutectic Alloy Depending on the Production Method

Scanning and transmission electron microscopy and X-ray diffraction have revealed that the eutectic 5 wt.% Mo-doped WC–W2C alloy changes its cooling rate in the melt crystallization process when produced in the Tammann furnace, by electron-beam evaporation, and by centrifugal sputtering. This increases the size of phase components by a factor of 2 to 2.5, decreases the number of phases, and reduces compressive stresses (in the W2C matrix) and tensile stresses (in the WC, Mo2C, and (W, Mo)2C inclusions) to 50% and more. These changes result in one and a half times higher hardness and two times higher strength of doped relit, which is widely used for surfacing machine parts and mechanisms operating in conditions of abrasive wear and high dynamic loads.

Optimal structure of wear-resistant compositional materials

The heterogeneous structure of composites is linked to their wear resistance under abrasive wear conditions. It was found that the DP content in the CEC corresponding to the highest strength of the wear-resistant material depends on the ratio of the strength properties of the matrix and the filler. It can be calculated using the continuum theory for the case of two-sided congestion of elliptical dislocations.

Production of Thermal Spray Cr<sub>3</sub>C<sub>2</sub>-Ni Powders by Mechanically Activated Synthesis

The aim of this research was to optimize the mechanically activated synthesis (MAS) technology of the Cr3C2-Ni powder intended for thermal spraying. The MAS production route included ball milling for 72 h (ball-to-powder ratio 20:1) and sintering under 1075 °C in vacuum for 4 h. Sintered compact was crushed, classified by sieving to obtain the fraction suitable for thermal spraying (20–45 μm). The morphology and the phase composition of the powder were analyzed by a scanning electron microscope (SEM) and X-ray diffraction (XRD). The optimal Cr:C ratio found was 7:1. The powder had an equiaxial or a slightly elongated lamellar shape, Cr3C2 carbides in a single powder particle had an elongated shape. The principal phases in the optimized powder were Cr3C2, Cr7C3 and Ni (Cr) solid solution. Coatings from the manufactured powder were produced by the high velocity oxy-fuel (HVOF) spraying. The abrasive wear tests were carried out according to standard ASTM G65. The wear tests showed that the sprayed coatings from the experimental powder exhibited about five times higher wear rate at abrasive wear conditions than the coatings from the reference commercial powder.