High Abrasive Wear Resistance Research Articles

Effect of increase of chrome and carbon content in the cored wire of Fe-C-Si-Mn-Cr-Ni-Mo-V system on physical and mechanical properties of built-up metal

Building-up of a layer, having high hardness, abrasive and shock-abrasive wear resistance on worn surfaces of mining equipment is the most perspective direction of their repair and restoration. For these purposes special building-up cored wires are used, development and production of which is made in both Russia and abroad. The aim of the research was to study the effect of chrome and carbon content in the blend of a new Fe-C-Si-Mn-Cr-Ni-Mo-V system cored wire on microstructure, wear and hardness of built-up metal. As a filler (blend) powdered materials were used: iron ПЖВ 1, ferrosilicon ФС 75, high-carbon ferrochrome ФХ 900 А , carbonaceous ferromanganese ФМн 78( А ), nickel ПНК -1 Л 5, ferromolybdenum ФМо 60, ferrovanadium ФВ 50 У 0,6, cobalt ПК -1 У , tungsten ПВН . Samples of the wire were made at a laboratory facility by multiple drawing through draw plate. The building-up by the manufactured wire was made in three layers under flux АН -26 С at a welding machine ASAW-1250 with the following parameters: I = 500 А , U = 29 V, V weld = 15 m/h. Results of the study of chemical composition, hardness and wear resistance of the built-up layers presented. A dependence of built-up layer hardness and its wear resistance on mass share of elements comprising the composition of the studied cored wires. It was shown, that the increase of hardness and decrease of wear speed takes place due to forming of martensitic structure of the built-up metal and due to increase of volume share of carbide phase of chrome when increasing chrome content from 1.8 until 5.2%, and carbon from 0.20 until 0.28%.

Formation of Dissipative Structure of Metastable Austenite for Raising the Abrasive Wear Resistance of Steels of Pearlitic and Ledeburitic Classes

The structure of retained austenite in wear-resistant steels 150KhNML and Kh12MFL of pearlitic and ledeburitic classes is studied under the conditions of abrasive wear after different variants of heat treatment. The working surfaces of the steels are subjected to electron microscope transmission analysis. It is shown that the retained austenite formed as a result of high-temperature quenching (1100 – 1170°C) is metastable and transforms in the wear process into fine- and nanocrystalline strain martensite with regular periodic arrangement of crystals in addition to slip and twinning. This provides a high capacity of the working surface for friction hardening. The optimum mode of heat treatment for formation of a dissipative structure with high abrasive wear resistance is chosen.

Mining tailings as a raw material for glass-bonded thermally sprayed ceramic coatings: Microstructure and properties

Magnesium aluminate, MgAl2O4, spinel powders for thermal spraying, were synthesized from secondary raw materials by spray drying and subsequent reaction sintering. Talc ore mining tailings and aluminium hydroxide precipitate from aluminium anodizing process were studied. A stoichiometric MgAl2O4 spinel coating was prepared as a reference using pure raw materials. Atmospheric plasma spraying resulted in the formation of ceramic coatings. Microstructural investigations revealed that the reference coatings exhibited crystalline lamellar microstructure of MgAl2O4 but secondary coatings contained amorphous areas between the crystalline MgAl2O4 clusters. Abrasive wear test results revealed considerably lower wear rate for secondary coatings. It is suggested that the different structure of coatings, particularly the high degree of amorphous phase between the isolated crystalline MgAl2O4 clusters caused the higher abrasive wear resistance by changing the wear mechanism. The dielectric breakdown strength of the secondary coatings were at the same level, 24 V/μm, as compared to reference coating, 23 V/μm.

Influence of the different variants of the surface treatment on the durability of forging dies made of Unimax steel

The study performs an analysis as well as makes a comparison of the durability of forging tools used in the die forging process made of high-strength steel Unimax. For tool steel WCL (1.2343 according to DIN), which has been applied so far, the obtained average durability has been at the level of about 6000 forgings. Additionally, in order to increase the durability of the Unimax material, two surface treatment variants were applied: in the form of ion nitriding (for nitrides A) and gas nitriding together with a PVD-Alvin coating, which were compared with the results for an insert without surface treatment. For each variant, three tools were produced, in order to obtain repeatable and verified results. In the first place, an analysis of the working conditions of the tools was performed through thorough observations of the industrial forging process, particularly the tribological conditions, including the manner of lubrication as well as the temperature distributions, by means of, among others, thermovisual examinations. Additionally, numerical modeling of the process was carried out with the purpose of a more accurate analysis of the tool work in contact. Next, a detailed analysis of the exploitation of the worn tools was performed, including a macroscopic and geometrical analysis through 3D scanning, microscopic optical, and SEM tests as well as microhardness measurements. The obtained results demonstrated that only the application of the new material, Unimax, itself caused a durability increase by 2.5 times with regard to the WCL steel used so far. In turn, with the application of additional surface engineering techniques, Unimax tools characterized in better operational properties (high thermal and abrasive wear resistance at elevated temperatures), which made it possible to forge over four times more forgings, i.e., 26,000 items, after nitriding with a PVD-Alvin coating had been applied to the tool.

INDUSTEEL D2

Abstract Industeel D2 is an air-hardening, high-carbon (1.5%), high-chromium (12%), alloy cold-work tool steel that also contains molybdenum and vanadium. It is specifically designed to provide high abrasive wear resistance and high hardenability. This grade can be used for cutting and deformation tools submitted to high abrasive wear. It can be used when Type D3 tool steel shows an excessive sensitivity to cracking or chipping. This datasheet provides information on composition, physical properties, hardness, and elasticity. Filing Code: TS-791. Producer or source: Industeel France (a subsidiary of ArcelorMittal.

Improvement of mechanical properties by means of titanium alloying to steel teeth used in the excavator

The effect of Ti addition (0.15 and 0.20 wt%) on mechanical properties and wear resistance of steel excavator bucket teeth was investigated. Teeth were produced by commercial sand casting technique. After production normalizing, hardening, and tempering heat treatment procedures were applied to the teeth. Lath martensitic microstructure was observed and small amount of carbide particles were present in the microstructures of Ti containing ones. In addition, small amount of hard and brittle TiN particles were observed in the microstructure of 0.20 wt% Ti containing teeth. The best mechanical properties were obtained for 0.15 wt% Ti containing teeth with considerably high abrasive wear resistance. However, 0.20 wt% Ti containing teeth exhibited worst abrasive wear resistance and limited ductility due to the formation of TiN particles.

Wear behavior of composite strengthened gray cast iron by austempering and laser hardening treatment

The present study mainly investigated the phase transformation and wear performance of laser hardened austempered gray cast iron specimens. Ball-on-Plate reciprocating sliding wear tests with PAO4 base oil were carried out on untreated, quench-tempered, austempered, laser hardened austempered gray cast iron specimens. Micro hardness profiles and worn surfaces were analyzed for specific wear mechanisms. It was found that four different zones were formed beneath the laser hardened surface including laser hardened zone (Ledeburite, ≈67HRC), upper heat affected zone (Martensite, ≈69HRC), lower heat affected zone (Tempered Ausferrite, ≈36HRC) and substrate (Ausferrite, ≈39HRC). In the sliding wear tests, the laser hardened austempered gray cast iron specimens showed higher wear resistance than others, which could be associated with the benefits of ausferritic structure with high fracture toughness and laser hardened regions with high hardness. By observing the worn surface, grooves and micro-sized material removal occurred within the substrate. The surface of the substrate ploughed by the asperities of the ball and hard wear debris stopped on the edge of the laser hardened regions since ledeburite and martensite had high hardness and abrasive wear resistance. However, some micro-cracks and spalls were developed within the laser hardened zone. The results obtained from this study could be used as reference in future research and applications of laser hardened austempered gray cast iron.

Laser cladding of Co-based metallic powder at cryogenic conditions

Purpose: of this paper was demonstration a novel technique of laser cladding by experimentally composed Co-based metallic powder and forced cooling of the substrate by liquid nitrogen under cryogenic conditions, at the temperature -190°C, for producing clad layers with enhanced microstructure characteristic and properties. Design/methodology/approach: Technological tests of laser cladding were conducted by means of a high power fibre laser HPFL with maximum output power 3.0 kW, and six-axis robot. The experimental Co-based powder was composed for providing high abrasive wear resistance, high resistance for impact load, and also for corrosion resistance at elevated temperature. The unique and novel technique of forced cooling of the substrate was provided by immersing the specimens in the liquid nitrogen bath. The three coaxial nozzle head was designed and custom made to provide precise deposition of the powder delivered into the laser beam irradiation region. The scope of the study included tests of conventional laser cladding at free cooling in ambient air in a wide range of processing parameters, and also trials of laser cladding under cryogenic conditions. The test clad layers produced by conventional laser cladding and by the novel technique of laser powder deposition under cryogenic conditions were investigated and compared. Findings: The obtained results indicate that the novel technique of forced cooling the substrate by liquid nitrogen bath provides lower penetration depth, as well as low dilution of the clad, and also provides higher hardness of the clads. Additionally, it is possible shaping the geometry of the individual bead, providing high reinforcement and low width. Research limitations/implications: The presented results are based just on preliminary test of the novel technique of laser cladding under cryogenic conditions. Therefore, further study and detailed analyse of the influence of the cooling rate on the quality, microstructure, and properties of the deposited coatings are required. Practical implications: The study is focused on practical application of the novel technique for manufacturing of wear resistance coatings characterised with enhanced performance compared to conventional range of application of the laser cladding. Originality/value: Novel technique of laser cladding at forced cooling under cryogenic conditions was demonstrated. The powder used for cladding trials was experimentally composed (not commercially available). The experimental stand custom made was used with custom made powder feeding rate, and also with custom made coaxial nozzle head.

Optimization of Vanadium Content for Achieving Higher Wear Resistance and Hardness in High Cr-V White Cast Irons for Ball Tube Mill Liner Application

The liner materials, being used, at present from high Cr cast iron grades in coal fired tube mills are less promising due to lower combination of abrasion wear resistance, hardness and impact toughness properties, thus giving life of only 25,000 to 35,000 hours. In this study, focus was given to develop a high Cr-V cast iron of high abrasion wear resistance with higher hardness and impact strength for ball tube mill liner application. The developed liner possesses high abrasive wear resistance and impact resistance simultaneously for having life of 40,000 to 50,000 hours. This grade was made using induction melting and sand casting method. The casting was heat treated in two stages to achieve higher abrasion wear resistance and mechanical properties. Various tests like chemical analysis, abrasion wear, hardness and impact tests were conducted on the above developed material. Abrasion wear test results show a low wear loss value (2.7 to 4.4 mg/min). Hardness and impact tests show a high combination of hardness (57 to 64 HRC) and impact strength (44 to 57 J/cm2). Prototype tube mill liners were manufactured and tested in a tube mill at 250MW site. Results obtained from site testing are also discussed in this study.

SPS of ”Titanium Carbide/Carbohydride – Copper” Composites

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Phase transformation of Nb2O5 during the formation of flame sprayed coatings and its influence on the adhesion strength, abrasive wear and slurry erosive wear

The development of research related to the characterization of niobium pentoxide (Nb2O5) has been of great interest in the scientific and commercial community due to promising performances in bio-electrochemical applications, advanced catalysts and corrosive environments. In this work, layers of 250 µm, 350 µm and 550 µm of Nb2O5 were deposited by low-speed flame spray on NiAl-bond coated AISI 1020 steel substrates. The phase transformations of Nb2O5, which occur during the formation of the layers, were studied as a function of deposited thickness and further correlated with adhesion, abrasion and slurry erosion resistance. X-ray diffraction analyzes of the coatings were performed for the study of the phases in the process. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) with dispersive energy microanalysis (EDS) were used to help microstructural analysis. The adhesive strength of the layers was evaluated by ASTM C633-13 and correlated with abrasion (ASTM G65-16) and slurry erosion wear resistance. From the microscopy analysis, a dense layer was observed with good interconnection at the interface Nb2O5-NiAl, with presence of pores typical of the thermal spray process. The XRD diffractograms of the niobium oxide coated samples show similar results regardless of the coating thickness (250, 350 and 550 µm) presenting superior compatibility with the hexagonal Nb2O5 and the monoclinic NbO2.46 (Nb22O54). The significantly higher intensities of the hexagonal Nb2O5 peaks suggest that it is the predominant phase. The thinner coatings, 250 and 350 µm, had higher adhesive strength, with a mean fracture stress of 16.12 MPa and 15.27 MPa, respectively. Nb2O5 thinner coatings showed also higher abrasive wear resistance when compared to "D2" tool steel and "H13" chrome tool steel. The thicker coatings (550 µm) had a mean adhesive strength of 13.73 MPa. From the abrasive wear tests, thicker coatings showed a greater volume loss of 41.18 mm3. The 550 µm coating presented higher slurry erosion resistance at a 30° particle impact angle, with a lower volume loss (12.93 mm3).

The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel

The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.

Tool wear and chip formation during dry high speed turning of direct aged Inconel 718 aerospace superalloy using different ceramic tools

Direct aged Inconel 718 superalloy is used in manufacturing critical cross-sections of aero-engine components. It is a hard-to-machine material, especially in dry conditions. To perform successful machining operations for this alloy, cutting tools with high hot hardness and chemical stability are required. The present study investigates the tool wear and chip formation during dry finish turning of direct aged Inconel 718 superalloy (51–53 HRC) using different ceramic tools. Pure alumina with added ZrO2 and alumina matrix reinforced with silicon carbide whiskers tools were used at cutting speeds of 150 and 250 m/min. A scanning electron microscope and energy dispersing spectroscopy were utilized to study the tool wear mechanisms. Structural and phase transformations during cutting on the tool–chip interface at the higher cutting speed were analyzed with X-ray photoelectron spectroscopy. Chip-undersides and cross-sections were studied with scanning electron microscope to investigate the chip formation mechanism. Results reveal that pure alumina with added ZrO2 can be an adequate choice for machining direct aged Inconel 718 because of its higher abrasive wear resistance and the formation of a sapphire protective tribo-layer at the tool–chip interface under severe cutting conditions. Chipping and notching of the cutting edge was found to decrease with the rise of the cutting speed for this tool material. As confirmed by X-ray photoelectron spectroscopy, alumina reinforced with silicon carbide whiskers tool was found to have a lower performance due the chemical degradation of the whiskers, especially at the higher cutting speed (250 m/min).

Effect of the simultaneous Ti and W addition on the microstructure and wear behavior of a high chromium white cast iron

The present work analyzes the effect of 0.7%Ti and 1.7%W addition to a 17% chromium white iron in as-cast condition and after destabilization heat treatment. These alloys are commonly used in applications where a high abrasive wear resistance is required. For this reason, in addition to the characterization, a complementary wear test was performed. The alloys were characterized by optical and electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The simultaneous Ti and W addition promoted the (Ti,W)C primary carbides formation which grow in the early stages of solidification. These carbides were found well distributed in the iron matrix with an average hardness value of 2450 HV. Moreover, tungsten was found partially distributed in the different phases increasing the microhardness by solid solution and refining the eutectic carbide. These microstructural modifications resulted in the increase of the bulk hardness and abrasive wear resistance of the alloyed iron. After destabilization heat treatment, the carbide precipitation and the matrix transformation produced a secondary hardening reducing the wear losses. Based in the results of the present study, the simultaneous addition of these elements to promote the (Ti,W)C carbide formation during solidification represents an effective method to increase the hardness and wear resistance of these kind of alloys via small additions.

Mechanosynthesis of TiC(NbC)–Cu composites using liquid hydrocarbons

The high-energy ball milling of Ti, Nb and Cu powders in liquid hydrocarbon and magnetic pulse compaction have been successfully used to produce Ti2CH0.6–(CuTi2,CuTi) and NbC–Cu composites with a density of 94–97% of the theoretical value, a microhardness of 4–5GPa and high abrasive wear resistance

Crack Restraining Methods and their Effects on the Microstructures and Properties of Laser Cladded WC/Fe Coatings.

Laser cladded WC/Fe coatings have the advantages of low cost and high abrasion wear resistance. However, cracks always appear in WC/Fe coatings, which limits their industrial application. In this paper, the co-effects of the re-melting process, heat treatments, and amount of Co element on the cracking susceptibility, microstructures, and mechanical properties of WC/Fe laser cladding coatings were studied. Experimental results show that re-melting process is helpful to improve the surface quality of the coating and to reduce the cracking susceptibility. The hardness of the coating decreases slightly but distributes more uniformly. Cracks in the coating can be inhibited effectively by preheating the substrate to 250 °C and maintaining the temperature during the laser cladding process, as well as applying an annealing treatment at 300 °C for 1 h. Heat treatment also results in a slight decrease in the hardness. Crack initiation cannot be restrained completely by applying the above two methods when laser cladding a big area of coating. On the basis of the above two methods, addition of Co element to the coating can further improve its toughness and decrease the crack susceptibility. Crack-free WC/Fe coating can be manufactured when 8% Co is added, and its wear resistance is much better than that of the hardened medium steel, especially when the wear time is long.

Microstructure evolution and mechanical properties of in-situ bimodal TiC-Fe coatings prepared by reactive plasma spraying

An in-situ synthesis phenomenon of bimodal TiC-Fe coatings is discovered in the reactive thermal spraying of Fe-Ti-C composite powders. The Fe-Ti-C composite powders were prepared by a hybrid spray-drying/pyrolysis technology using a mixture of ferrotitanium (TiFe), graphite and sucrose. The microstructure evolution and mechanical properties of the coatings were investigated. The results showed that the TiC-Fe coatings exhibited an apparent bimodal particle size distribution of submicron and nano TiC particles in the α-Fe matrix. The formation of the bimodal distribution structure was revealed as following bi-precipitation mechanism: the first precipitation during the flight process to form submicron TiC particles and the second precipitation in the impact process with rapid cooling to form nano TiC particles. The bimodal TiC-Fe coatings showed high microhardness in various loads due to simultaneous hardening effect from submicron and nano TiC particles. The crack analysis showed that the in-situ bimodal TiC structure hindered the crack initiation and the crack propagation and thus improved the fracture toughness. The bimodal TiC-Fe coatings exhibited high abrasive wear resistance and the wear mechanism transformed from two-body abrasive wear to three-body abrasive wear with the increase of spray distances.

Fabrication and characteristics of sintered copper-silica composites

The paper presents the results of research on the production of a sintered Cu-SiO2 composites fabricated by powder metallurgy. The starting materials for obtaining the composites were commercial powders: Cu and SiO2. SiO2 particles were introduced into a copper matrix in the amount of 2.5 %, 5 %, 7.5 % and 10 % by weight. Finished powders mixtures were subjected to single pressing with a hydraulic press at a compaction pressure of 620 MPa and then subjected to sintering process at 900 °C in an atmosphere of dissociated ammonia. The sintering time was 60 minutes. The sintered compacts were subjected to the following tests: hardness, measurement of density, electrical conductivity and abrasion resistance. The highest density was obtained for a composite containing 2.5 % SiO2 which was 7.94 g/cm3. The highest hardness was obtained for a composite containing 10 % SiO2 which amounted to 50 HB. For the composite containing 2.5 % SiO2 the highest electrical conductivity was obtained which was 47 MS/m. The highest abrasive wear resistance was obtained for a composite containing 10 % SiO2. Both density and electrical conductivity decreased along with the increase of SiO2 content in composites.

Effect of Microstructures on Working Properties of Nickel-Manganese-Copper Cast Iron

In the paper, the effects, on basic usable properties (abrasive wear and corrosion resistance), of solidification (acc. to the stable and non-stable equilibrium system) and transformations occurring in the matrix during the cooling of castings of Ni-Mn-Cu cast iron were determined. Abrasive wear resistance was mainly determined by the types and arrangements of high-carbon phases (indicated by eutectic saturation degree), and the kinds of matrices (indicated by the nickel equivalent value, calculated from chemical composition). The highest abrasive wear resistance was found for white cast iron, with the highest degree of austenite to martensite transformation occurring in its matrix. Irrespective of solidification, a decrease of the equivalent value below a limit value resulted in increased austenite transformation, and thus, to a significant rise in hardness and abrasive wear resistance for the castings. At the same time, corrosion resistance of the alloy was slightly reduced. The examinations showed that corrosion resistance of Ni-Mn-Cu cast iron is, too a much lesser degree, decided by the means of solidification of the castings, rather than transformations occurring in the matrix, as controlled by nickel equivalent value (especially elements with high electrochemical potential).

Aplicación del ajuste de Rietveld para correlacionar la evolución microestructural de fundiciones blancas con 18 y 25% en Cromo, templadas en aceite y sucesivos revenidos, con el comportamiento frente al desgaste abrasivo y esfuerzos de flexión

Mediante la aplicación del método de afinamiento estructural de Rietveld se identificaron y cuantificaron las fases presentes en fundiciones blancas hipoeutécticas con 18 y 25% en Cromo, templadas en aceite y tras sucesivos revenidos a 500 ºC. Se correlacionaron los resultados con su comportamiento frente al desgaste abrasivo y bajo esfuerzos de flexión. En ambos casos el porcentaje de austenita retenida tras el temple resultó mínima. Durante los sucesivos revenidos, se constató en la calidad con 18% en Cromo una redisolución parcial de los carburos M7C3 junto a una transformación entre carburos mixtos secundarios M7C3 y M2C. La Martensita tras temple resultó un factor clave frente a la resistencia al desgaste abrasivo, resultando los revenidos tras el temple en aceite desfavorables para esta propiedad. La calidad con 25% en Cromo fue la que presentó un mayor contenido en martensita tras el temple, y por tanto la que mejor comportamiento presentó frente a este tipo de desgaste. Esta misma calidad, tras el doble revenido, fue la que mayor resistencia y capacidad de deformación alcanzó bajo esfuerzos a flexión. La fractura resultó frágil y mayoritariamente transgranular. Sin embargo, pudo observarse la presencia de zonas con fractura dúctil asociadas a martensita doblemente revenida.