Wear Resistance Of Surface Layer Research Articles

Eutectic resolidification and ultrafast self-quenching of the microstructure in the surface layer of high-speed steel by scanning electron beam treatment

Improving the service life and efficiency of high-speed steel (HSS) tools remains a formidable challenge. Herein, scanning electron beam (SEB) was employed to modify the surface of M2 HSS. Results revealed that SEB induced eutectic resolidification and ultrafast self-quenching of microstructure in surface layer of HSS. The melted layer exhibited a microstructure comprising martensite, residual austenite, dispersed finely rod-like MC and lamellar M2C eutectic carbides along grain boundaries. Martensite and eutectic carbide grid structure significantly enhanced the hardness and wear resistance of surface layer. Compared to substrate, the microhardness of SEB sample was elevated by more than threefold, reaching 914.7HV0.2, which exceeded the hardness (828.6HV0.2) of conventional quenching treatment. Notably, the wear volume of SEB sample had been reduced to 0.54 × 10−11 m3, resulting in a wear resistance that was 3.8 times greater than that of quenched sample.

Functional properties of expanded austenite generated on AISI 316L by plasma nitrocarburizing using different active screen materials

Abstract This study investigates the functional properties of the expanded austenite layers generated on AISI 316L austenitic stainless steel resulting from active screen plasma nitrocarburizing using different active screen materials, i.e. steel or solid carbon. Treatments were conducted at 460 °C for 5 hours in a nitrogen-hydrogen feed gas, whereas for the treatments using a steel active screen, methane was added as carbon precursor. Additionally, the bias plasma conditions applied at the samples were varied between 0 kW and 1.25 kW. Samples were characterized by complementary microstructural and compositional investigations, surface roughness and hardness measurements, pin-on-disk tribological tests as well as potentiodynamic polarization tests in H2SO4 and NaCl electrolytes. The functional properties of the case are discussed based on the contents of nitrogen and carbon in the expanded austenite and on their effective diffusion depths. The results show that the usage of a carbon screen generally produces surfaces with uniform layer thickness, high hardness, improved wear resistance and a delayed tendency to pitting corrosion independent of the bias condition applied to the samples. When applying both screen materials at non-biased condition, the general corrosion resistance is slightly reduced under the conditions used, however, the layers generated using the carbon screen have a wear rate that is 3 times lower. It can be concluded that the carbon screen represents a robust treatment variant for austenitic stainless steels to produce sufficiently thick and wear-resistant surface layers in a short treatment duration, which still have the potential to maintain the corrosion resistance in different environments.

Повышение износостойкости цилиндрических поверхностей трения комбинированной электромеханической обработкой

Processing technology and technological equipment for the formation of a wear-resistant surface layer by implanting materials based on tungsten carbide (WC), are viewed. The effect of implanted WC powder on the formation of gradient wear-resistant structures in the friction surface of carbon steel formed during the implementation of combined electromechanical processing (WRCEMP) technology, has been studied. Resulting from heat and pressure impact in the zone of plastic deformation, intensive austenization of steel occurs with dissolution of WC powder and subsequent formation of highly dispersed composite structures caused by the decomposition of undercooled tangstem-supersaturated austenite. Combined comparative friction and wear tests were carried out for structural steel 45 with a graded structure of a hardened surface and rather expensive and technologically- difficult to obtain modern wear-resistant coatings and materials. The issue of WRCEMP technology practical application used for the «axis of satellite – satellite» friction pair is viewed. An assessment of the durability increase of the «axis of satellite – satellite» interface during the implementation of the considered processing methods and innovative technology was taken. Recommendations for the use of combined electromechanical processing technology at machine-building enterprises as a highly effective way to ensure and improve the performance of machine parts at the stage of their manufacture are given.

Development of technology to restore the working area of the stamp tool

Subject of research: technology for restoring the working area of a stamp tool, the structure and properties of the deposited layer of the restored stamp surface.
 Purpose of research: to develop a technology for restoring the working area of a hot deformation die insert for the formation of a gradient structure and properties of the metal over the cross section of the deposited zone.
 Methods and object of research: a technology for restoring the insertion of a worn hot-forming stamp on the beam of the front axle of a KAMAZ truck using two-layer electric arc surfacing with one type of electrode wire is presented. To obtain a gradient structure in the section of the working area of the die, heat treatment is proposed, which consists in tempering the die after the first surfacing at a temperature of 62010C, and after the second surfacing at a temperature of 52010C.
 Main results of research: it was found that after the restoration of the hot deformation die insert, the hardness of the deposited metal of the first (deep) layer was 3436 HRC, the structure was tempered troostite, the hardness of the second (outer) layer was 4246 НRC, structure tempered martensite and troostomare-tensite. This ensures high wear resistance of surface layers and crack resistance in the depth of the die metal.

Investigation of the surface layer of wheel steel by indentation method

The article considers methods of measurement of microhardness and modulus of elasticity of plasma hardened wheel steel by kinetic indentation method. It provides features of measurement of microhardness, modulus of hardness, elastic recovery, influencing on wear resistance of surface layers of steel. Measurement of these characteristics of material allows estimating and choosing optimum technology of surface modification by surface plasma hardening. It is confirmed that objectivity of determination of microhardness, modulus of elasticity, elastic recovery and flow stress depends on strict observance of imprint depth requirements depending on thickness of hardened layer. It is noted that in spite of the increased amount of factual information, obtained by indentation method, the physical substantiation of hardness micro-mechanisms remains poorly understood, which necessitates substantiation of physical representations of the nature of hardness of metallic materials. It is established that the measurement of microhardness, elastic modulus and elastic recovery by the kinetic indentation method is expedient to use for certification of the surface layer of plasma-hardened wheel steel according to the parameters of physical and mechanical characteristics.

Inverse Thermal Analysis as a Tool for Optimizing Concentrated Solar Energy Elaboration of Wear Resistant Surface Layers

Concentrated Solar Energy (CSE) processing is considered a promising renewable energy source technique for elaborating thick, wear-resistant claddings onto metallic surfaces of large dimensions that are expected to operate in heavy duty applications, such as excavator shovels, mineral crushers, etc. However, the prediction of surface processing effects on the microstructure and the properties of the main construction base metal are of crucial importance, as they are commonly required in all surface modification techniques. Thus, the present study is focused on the inverse thermal analysis and parametric modeling of heat deposition associated with CSE surface processing of metals. In this preliminary attempt, experimental findings that concern the elaboration of TiC- and chromium carbide-reinforced clads onto common steel base metals were used to quantify the evaluation of the temperature histories within the volume of workpieces undergoing solar heating, where direct temperature measurements contain uncertainties and/or are not even possible. Results of prototype inverse thermal analyses of heat transfer in processed layer-substrate systems are presented, demonstrating the general aspects of a parametric model for thermal analysis and simulation.

Increasing the wear resistance of surface layers of selected steels by TIG electric arc surface remelting process using a powder based on CaCN2

Increasing the wear resistance of surface layers of selected steels by TIG electric arc surface remelting process using a powder based on CaCN2

Exploratory Data Analysis for the Evaluation of Tribological Properties of Wear-Resistant Surface Layers Modified with Rare-Earth Metals

The role of rare Earth metals in the improvement of the properties of metals and alloys has been analysed and described in multiple studies. Their effects on changes in microstructure and mechanical properties are most pronounced. This paper focuses on the beneficial effect of rare Earth metal oxides on the wear resistance of surface layers applied to castings intended for structural elements of machinery and equipment in mining and recycling. The experiment involved modifying prepared surfaces by adding CeO2, Y2O3, and La2O3. Hardness measurements, a scratch test, and tribological tests were performed under dry and fluid friction. The maximum wear track depth and track area were measured from the surface profile. To determine correlations between the results, exploratory data analysis was employed. Heatmaps were used to illustrate strong positive and negative interactions. The addition of oxides at increasing carbon content resulted in increased hardness, lower coefficient of friction, and reduced track area and maximum track depth. Strong negative interactions between the track area and maximum track depth were found. The differences resulting from the test conditions (fluid and dry friction) were discussed. This study demonstrated the suitability of exploratory data analysis for analysing research results and confirmed the improvement of modified surface wear resistance.

Effect of Carbon Content and Boronizing Parameters on Growth Kinetics of Boride Layers Obtained on Carbon Steels.

Boronizing is a thermochemical treatment performed to produce hard and wear-resistant surface layers. In order to control the process and obtain boride layers with the desired properties, it is very important to know how the boronizing parameters and the chemical composition of the treated steel affect the boronizing. The aim of the present study is to investigate the influence of carbon content in carbon steels, boronizing temperature, and boronizing duration on the growth kinetics of boride layers. For this purpose, three carbon steels (C1y5, C45, and C70W2) were boronized in solid medium. The experimental results show that there is a linear relationship between the carbon content and the activation energy values, and between the carbon content and the frequency factors. In addition, a statistical analysis was performed to determine the contribution of each factor. The ANOVA showed that boronizing temperature has the highest effect on the boride layer thickness, followed by the boronizing duration, while the carbon content of the steel has the least effect on the boride layer thickness. Based on a regression model, an empirical equation was derived to estimate the thickness of the boride layer on carbon steels as a function of carbon content, boronizing temperature, and duration.

Matrix Composite Coatings Deposited on AISI 4715 Steel by Powder Plasma-Transferred Arc Welding. Part 3. Comparison of the Brittle Fracture Resistance of Wear-Resistant Composite Layers Surfaced Using the PPTAW Method.

This article is the last of a series of publications included in the MDPI special edition entitled “Innovative Technologies and Materials for the Production of Mechanical, Thermal and Corrosion Wear-Resistant Surface Layers and Coatings”. Powder plasma-transferred arc welding (PPTAW) was used to surface metal matrix composite (MMC) layers using a mixture of cobalt (Co3) and nickel (Ni3) alloy powders. These powders contained different proportions and types of hard reinforcing phases in the form of ceramic carbides (TiC and WC-W2C), titanium diboride (TiB2), and of tungsten-coated synthetic polycrystalline diamond (PD-W). The resistance of the composite layers to cracking under the influence of dynamic loading was determined using Charpy hammer impact tests. The results showed that the various interactions between the ceramic particles and the metal matrix significantly affected the formation process and porosity of the composite surfacing welds on the AISI 4715 low-alloy structural steel substrate. They also affected the distribution and proportion of reinforcing-phase particles in the matrix. The size, shape, and type of the ceramic reinforcement particles and the surfacing weld density significantly impacted the brittleness of the padded MMC layer. The fracture toughness increased upon decreasing the particle size of the hard reinforcing phase in the nickel alloy matrix and upon increasing the composite density. The calculated mean critical stress intensity factor KIc of the steel samples with deposited layers of cobalt alloy reinforced with TiC and PD-W particles was 4.3 MPa⋅ higher than that of the nickel alloy reinforced with TiC and WC-W2C particles.

Mechanism and patterns of wear of chrome steels with a surface-modified layer

The paper presents the results of contact wear studies of surface layers of 6Cr4Mo2VSi steel under the action of pulsating contact stresses. Differences in wear resistance of surface layers of materials are shown, in interrelation with modes of synthesis of their structure and properties. The features of the evolution of the structure of modified layers strengthened by nitrocarburizing are revealed. The modes of thermo-chemical treatment for achieving maximum resistance to the action of pulsating contact stresses are determined.

NEW MATERIALS FOR THE PRODUCTION OF REPLACEABLE PARTS OF TILLAGE AGRICULTURAL MACHINERY

The analysis of results of practical application of cast replaceable details of hinged tillage agricultural machinery at operation in a number of the agricultural enterprises of the Poltava region at processing of more than 60 thousand hectares within several years is presented. Comparative data of the resource of parts made of high-strength bainitic cast iron and steel serial analogues of domestic and foreign production are given. The advantages of the method of manufacturing by casting methods in comparison with the traditional method of manufacturing by stamping. This technology allows you to easily make adjustments to the design of the cultivator legs, thus providing a new quality of tillage and pruning of the root system of weeds, which eliminates the need for herbicides. The basis of this technology is the use of composite complex modifiers made by rolling powder mixtures of plastic and brittle components with the necessary observance of the proportions of their ratio. The use of powder rolled modifiers provides the necessary properties and structure of the cast metal required for further heat treatment. It is substantiated to obtain high wear resistance of cast products due to the appearance of TRIP-effect and constant updating of wear-resistant surface layer during operation.

Microstructure and Abrasive Wear Resistance of Metal Matrix Composite Coatings Deposited on Steel Grade AISI 4715 by Powder Plasma Transferred Arc Welding Part 2. Mechanical and Structural Properties of a Nickel-Based Alloy Surface Layer Reinforced with Particles of Tungsten Carbide and Synthetic Metal-Diamond Composite.

The article is the continuation of a cycle of works published in a Special Issue of MDPI entitled “Innovative Technologies and Materials for the Production of Mechanical, Thermal and Corrosion Wear-Resistant Surface Layers and Coatings” related to tests concerning the microstructure and mechanical properties of innovative surface layers made using the Powder Plasma Transferred Arc Welding (PPTAW) method and intended for work surfaces of drilling tools and machinery applied in the extraction industry. A layer subjected to tests was a metal matrix composite, made using powder based on a nickel alloy containing spherical fused tungsten carbide (SFTC) particles, which are fused tungsten carbide (FTC) particles and spherical particles of tungsten-coated synthetic metal–diamond composite (PD-W). The layer was deposited on the substrate of low-alloy structural steel grade AISI 4715. The results showed that the chemical composition of the metallic powder as well as the content of the hard phase constituting the matrix enabled the making of a powder filler material characterised by very good weldability and appropriate melting. It was also found that the structure of the Ni-WC-PD-W layer was complex and that proper claddings (characterised by the uniform distribution of tungsten carbide (WC)) were formed in relation to specific cladding process parameters. In addition, the structure of the composite layer revealed the partial thermal and structural decomposition of tungsten carbide, while the particles of the synthetic metal–diamond composite remained coherent. The deposited surface layer was characterised by favourable resistance to moderate dynamic impact loads with a potential energy of 200 J, yet at the same time, by over 12 times lower metal–mineral abrasive wear resistance than the previously tested surface layer made of cobalt-based composite powder, the matrix of which contained the hard phase composed of TiC particles and synthetic metal–diamond composite. The lower abrasive wear resistance could result from a different mechanism responsible for the hardening of the spherical particles of the hard phase susceptible to separation from the metal matrix, as well as from a different mechanism of tribological wear.

Tribological and corrosion performance of the plasma-sprayed conformal ceramic coating on selective laser melted CoCrMo alloy

Ceramic implants have superior performance due to the excellent wear resistance and biocompatibility. However, the poor machinability limits their applications. Plasma sprayed ceramic coating on the additively manufactured metal substrate not only provides a 3-dimensional conformal implant coating and but also forms a highly wear-resistant surface layer. In this paper, three types of ceramic coatings of Al2O3, ZrO2, and Al2O3–ZrO2 composite have been fabricated by atmosphere plasma spray on the CoCrMo alloy substrate prepared by selective laser melting (SLM). It has been found that the Al2O3–ZrO2 composite coating has better corrosion and wear resistance compared with the ceramic coating (Al2O3, ZrO2) and the CoCrMo substrate. The adhesion strength between the Al2O3–ZrO2 composite coating and the substrate reaches 238 MPa. In addition, the wear and corrosion resistance increase with wear progression for all the fabricated ceramic coatings. The highly dense microstructure, fewer microcracks, and the amorphous phases are deterministic factors responsible for the superior tribological and corrosion performance of the Al2O3–ZrO2 composite coating. The fabrication route has been proved very promising to manufacture high-performance implants with ceramic coating.

Effect of Alloyed Coating Composition on Composite Casting Surface Layer Properties

A method of casting surface alloying during casting using gasified models with the formation of a wear-resistant surface layer is considered. The increase in wear resistance is due to formation of boride and carbide components by means of self-propagating high-temperature synthesis between alloyed coating components that occurs during casting manufacture. Results of comparative tests for materials under abrasive wear are presented. Data are given for material composition, structure, and hardness.

Многофазные покрытия Cu-Ti, нанесенные плазменным вакуумно-дуговым напылением на Cu-Be сплав С17200

Introduction. Deposition of hard intermetallic coatings is an efficient technology to improve operating characteristics of Cu-Be alloys. PVD of coatings is widely used for surface engineering of constructive materials, deposition of wear and corrosion resistant surface layers. Multiphase and multicomponent coatings are considered as the most efficient hard coatings for surface engineering. In this research, Ti-Cu coatings are deposited by a vacuum-arc plasma-assisted method on hardened BrB2 bronze (alloy C17200) at a temperature of 320 – 330 oC. Processing resulted in ageing of Cu-Be alloy and surface hardening of material. The aim of the research is to analyze the microstructure, phase composition, and tribological properties of Cu-Be alloys modified with plasma-activated PVD coatings based on titanium, with the subsequent development of an effective technology for surface engineering and improvement of the mechanical properties of Cu-Be alloys. Results and discussion. Plasma-assisted PVD of Cu-Ti coatings on the surface of tempered C17200 alloy at 320 – 330 oC resulted in formation of multiphase coatings, consisting of Cu, Ti, CuTi and CuTi2 components. X-ray analysis revealed development of ageing process in Cu-Be alloy which resulted in formation of CuBe inclusions. Wear resistance of modified blocks is investigated. The main mechanism of modified blocks wearing is cracking of the coating with further formation of fine debris of base Cu-Be material. Wear debris is significantly smaller then debris of С17200 alloy without coating. Surface microhardness of blocks processed at 320 –330 oC is comparatively high (540 HV0.02 - 530 HV0.02). Wear resistance of blocks subjected to surface engineering is comparatively low probably because of small thickness of the coating (< 8 µm) and insufficient hardness of matrix material.

Повышение износостойкости поверхностного слоя деталей комбинированной электромеханической обработкой с отпуском

Повышение износостойкости поверхностного слоя деталей комбинированной электромеханической обработкой с отпуском

Concentrated solar energy for in-situ elaboration of wear-resistant composite layers. Part II: Tungsten carbide surface enrichment of common steels

The present work constitutes the second part of a study concerning the application of Concentrated Solar Energy (CSE) for the in-situ elaboration of carbide-reinforced surface layers onto common steels, employing WC as a model system. As in the first part that involved titanium and chromium carbides as reinforcing compounds, “solar hardfacing” experiments were carried out in the solar furnace SF40, at the installations of Plataforma Solar de Almería (Spain). Parametric studies performed were targeted to clarify the effects of solar irradiation time and inert or reactive processing atmosphere on the structural integrity, microstructure, carbide dispersion and hardness of the surface layers obtained. The results were used, on the one hand to identify conditions for the elaboration of wear resistant surface layers and on the other hand to elucidate the fundamental mechanisms governing the dispersion of WC particles in a liquid ferrous matrix that is, subsequently, re-solidified. In contrast to the TiC particles, WC ones are subjected to liquid metal attack transforming progressively to mixed FeW carbides, as determined by scanning electron microscopy and X-ray diffraction. Under inert atmosphere, solar processing beyond a threshold time period decreases the in-depth homogeneity of the carbides dispersion and increases the extent of the attack, deteriorating hence the composite character of the layer obtained. Reactive nitrogen atmosphere mitigates the negative effects of prolonged exposure, allowing the elaboration of thick hardfacing layers. Finally, dry sliding friction tests allowed defining the friction coefficient and specific wear rate, as well as the synergy of the wear micro-mechanisms involved. These results complemented with the respective ones for titanium and chromium carbide-based hardfacing layers, provide a first framework for the rational and optimized elaboration of wear resistant carbide-based surface layers using concentrated solar energy.

TESTING THE STRUCTURE AND PROPERTIES OF STEELS AFTER HARDFACING AND LASER TREATMENT

This paper analyses the structure, hardness, and frictional wear resistance of surface layers formed on steels after hardfacing by means of the SSA arc method with self-shielded flux cored welding wire, with a content of carbon 5% and chromium 30% as well as boron alloying with the CO2 laser. S355J2 steel after being hardfaced with one up to three layers is characterized by the martensitic structure with chromium carbides and its surface hardness is 50–55HRC. In the weld deposit zone, with a thickness of up to approx. 2 mm, there is a constant distribution of hardness with the average value of 700 HV0.1, and then the hardness decreases to approx. 160 HV0.1 in the steel substrate. After hardfacing, the carbon content in S355J2 steel (0.23% wt.) increases to a similar content as in steel C90U in the initial state (0.96% wt.). After laser alloying with boron and after rapid cooling, C90U steel obtains distinctive paths with a zone structure and thickness reaching up to approx. 380 μm. In the remelted zone, there is a eutectic structure consisting of a mixture of iron borides and martensite with a hardness of approx. 1200–1800 HV0.1, and beneath it, there is heat affected zone with a martensitic-bainite structure with a hardness of approx. 700HV0.1. Hardfacing and laser heat treatment significantly decrease the frictional wear of the tested steels.

Creation of a Wear-Resistant Tungsten-Carbide Surface Layer on Carbon Steels by Implantation and Electromechanical Machining

The formation of a wear-resistant surface layer by the implantation of materials based on tungsten carbide is considered. The influence of implanted tungsten-carbide powder on the formation of wear-resistant gradient structures at the frictional surfaces during electromechanical machining is studied. Thermomechanical processes in the plastic-deformation zone result in intense austenitization of the steel, with the solution of tungsten-carbide powder and the formation of highly disperse composite structures on disintegration of the supercooled austenite supersaturated with tungsten.