This study focuses on the properties and process parameters dictating behavioural aspects of fric... more This study focuses on the properties and process parameters dictating behavioural aspects of friction stir welded Aluminium Alloy AA6061 metal matrix composites reinforced with varying percentages of SiC and B4C. The joint properties in terms of mechanical strength, microstructural integrity and quality were examined. The weld reveals grain refinement and uniform distribution of reinforced particles in the joint region leading to improved strength compared to other joints of varying base material compositions. The tensile properties of the friction stir welded Al-MMCs improved after reinforcement with SiC and B4C. The maximum ultimate tensile stress was around 172.8 ± 1.9 MPa for composite with 10% SiC and 3% B4C reinforcement. The percentage elongation decreased as the percentage of SiC decreases and B4C increases. The hardness of the Al-MMCs improved considerably by adding reinforcement and subsequent thermal action during the FSW process, indicating an optimal increase as it elim...
In this work a model of temperature field in a steel cast during surfacing was presented. Analyti... more In this work a model of temperature field in a steel cast during surfacing was presented. Analytical solution for half-infinite body model was obtained by aggregating temperature increments caused by applying liquid metal and heat radiation of moving electrode. The assumptions were Gaussian distribution heat sources of applied metal and weld and of electric arc heat source. Computations of temperature field were carried out during surfacing of cuboidal steel cast. The results were presented as temporary and maximum temperature distribution in element's cross section and thermal cycles at selected points. The accuracy of solution was verified comparing calculated fusion line to that obtained experimentally. Slowa kluczowe: Surface Treatment, Temperature Field, Welding, Surfacing
The wear-resistant layers of the chromium cast iron structure can be made by traditional casting ... more The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.
The paper presents the analysis of temperature fields, phase transformations, strains and stresse... more The paper presents the analysis of temperature fields, phase transformations, strains and stresses in a cuboidal element made from S235 steel, surfaced with multipass GMA (Gas Metal Arc) method. The temperature field is described assuming a dualdistribution heat source model and summing up the temperature fields induced by the padded weld and by the electric arc. Dependence of stresses on strains is assumed on the basis of tensile curves of particular structures, taking into account the influence of temperature. The calculations were carried out on the example of five welds in the middle of the plate made of S235 steel. The simulation results are illustrated in graphs of thermal cycles, volume shares of structural components and stresses at the selected points of cross-section, and the temperature and strain distributions in the whole cross section.
In work have been presented models of temperature fields and kinetics of phase transformations in... more In work have been presented models of temperature fields and kinetics of phase transformations in continuous casting steel machine roll surfacing spiral welding sequence with swinging motion of welding head. The temperature field was determined by analytical solution for massive body heated by moving voluminal heat source. The progress of diffusional phase transformations was described basing on equation of kinetics JMA-K and Koistinen-Marburger’s for martensitic transfomation. Deliberations were illustrated by computational example of surfaced roll made from steel 13CrMo4. The temperature field and structural components fraction was calcualated in section of regenerated area of material decline (along the roll axis). Considering critical temperatures, heat-affected zones have been determined: A1 and A3 – austenitic transformation, and solidus - fusion line. Accepted technological parameters of rebuilding gave results that reproduce geometry of padding weld heat-affected zones confi...
Modelling of technological processes of heat treatment or welding, involving multiple heat source... more Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the infl uence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coeffi cients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite). The analysis of tempering time infl uence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up) in technological processes based on short-timed action of a heat source (eg. laser treatment) have been suggested.
The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium a... more The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium and carbon surfaces. In these studies selfshielded cored wire was used as a material for hardfacing. Pulsed arc is used in welding technologies to better control of transport molten metal in the welding arc and heat input. The correct heat input results in limited dilution surfaces that is very important in wear prevention technologies. The paper presents the results of research on the geometric parameters and hardness of deposited surfaces. The investigation was carried out with various welding parameters that were designed in heat source. The survey was conducted on the specimens that were subjected to metallographic examination hardness test.
A new method of calculating the amount of heat introduced into the welded joint is presented. Ins... more A new method of calculating the amount of heat introduced into the welded joint is presented. Instead of the previously used measure of heat input per unit length, heat input per unit volume was proposed. The proposed method and general formula are based on the basic technological parameters of the welding process (i.e. energy generated by the electric arc and welding speed) and the cross-sectional area of the fusion zone in the welded joint. A simplified method of calculating heat input per unit volume is presented by using simple formulas to calculate the surface area of the fusion zone in cross-section of the weld for the most common shapes in classic welding methods. The proposed general formula allows for a more accurate way of calculating the heat input per unit of volume depending on the the energy generated by the electric arc (e.g. for pulse current) and the surface area of the reinforcement and fusion zone using other direct measurement methods.
In the paper, the method of calculating the welding energy needed to regenerate parts of agricult... more In the paper, the method of calculating the welding energy needed to regenerate parts of agricultural machines by welding (joining) or surfacing (rebuilding, hardfacing) is presented. Problems with the lack of adequacy of the commonly used formula for linear welding energy to the actual amount of heat introduced into the welded joint are discussed. A volumetric approach based on the effective amount of heat generated by the electric arc introduced per unit volume of the weld was proposed. The simplified formulas for volumetric energy are presented. The considerations are illustrated with examples of calculations. The analyzed examples include the use of a computerized stand for geometric measurements of metallographic specimens. The proposed volumetric method of calculating the amount of heat introduced into the welded joint is a more realistic indicator of heat demand than linear energy. On the other hand, based on the volume of the weld (padding weld), it allows to determine the a...
Abstract In this study, we present a novel fixed-grid interface-tracking method using finite volu... more Abstract In this study, we present a novel fixed-grid interface-tracking method using finite volume method to simulate multidimensional rapid solidification (RS) of under-cooled pure metal. The discretized advection equation for solid fraction function is solved using the THINC/WLIC method, which is a VOF method. The governing equations for fluid flow are solved numerically using pressure-velocity coupling SIMPLE algorithm in a 2-D model with incompressible Newtonian fluid. The energy equation is modeled using an enthalpy-based formulation. The nonequilibrium solidification kinetics, interface tracking, undercooling, nucleation, heat transfer, and movement of liquid are included in the presented RS model.
Proceedings of the 2nd EAI International Conference on Management of Manufacturing Systems, 2018
In work the model of stress calculation and analysis of stress field during single-pass SAW (Subm... more In work the model of stress calculation and analysis of stress field during single-pass SAW (Submerged Arc Welding) surfacing have been presented. In the temperature field solution, influence heat of melted electrode and heat of direct impact of electric arc have been taken into consideration. The phase change kinetics according to the laws of Johnson-Mehl-Avrami-Kolmogorov and Koistinen-Marburger were determined. The temperatures of the beginning and the end of the changes were determined by the A c1 and A c3 temperatures during heating and on the basis of the timetemperature-transformation welding diagram for cooling. The stress state of thermal loaded flat has been described assuming planar section hypothesis and simple Hooke's law and using integral equations of stress equilibrium. The stress-strain curves were modeled as the curves of the mixture of individual material phases depending on temperature. The analysis of stress state has been presented for SAW surfacing S355 steel plate.
The paper presents the capabilities of welding techniques to creating properties of wear resistan... more The paper presents the capabilities of welding techniques to creating properties of wear resistant high chromium cast iron alloy. The use of the right kind of welding sequence allows you to change the structure and properties of the obtained welds. Tests were conducted for one type of additive material in the form of self shielded core wire. In order to determine the effect of the type of welding sequence on the properties of welds performed welding using string bead and weave bead. The resulting weld was tested on hardness and research structure in an optical microscope. In the following studies have been made erosive tests wear of made hardfacing. String beads gave structure rich in carbides and harder about 270 HV of the weld with weave bead. Also, wear resistance was nearly twice as better for welds made with string beads. In the experiment a decisive role in the resistance to wear plays a high hardness of the deposit and the presence of carbides in its structure. Changes in the...
The paper presents a model of temperature, phase transformation and stresses fields in a steel el... more The paper presents a model of temperature, phase transformation and stresses fields in a steel element during single-pass Gas Metal Arc Weld (GMAW) surfacing.Kinetics of phase transformations during heating is limited by temperature values at the beginning and at the end of austenitic transformation, while the progress of phase transformations during cooling is determined on the basis of TTT-welding diagram and Johnson-Mehl-Avrami and Kolomogorov law for diffusive transformations and Koistinen-Marburger for martensitic transformation. Stress state of a bar subjected to thermo-mechanical loads is described assuming the plane cross section hypothesis and using integral equations of stress equilibrium of a bar as well as simple Hook’s law. Stresses in the elastic-plastic state are determined by iteration using solutions with a variable elastic modulus of elasticity, conditioned by tensile curves. Dependence of stresses on strains is assumed on the basis of tensile curves of particular ...
The paper is focused on the modeling of the directional solidification process of pure metal. Dur... more The paper is focused on the modeling of the directional solidification process of pure metal. During the process the solidification front is sharp in the shape of the surface separating liquid from solid in three dimensional space or a curve in 2D. The position and shape of the solid-liquid interface change according to time. The local velocity of the interface depends on the values of heat fluxes on the solid and liquid sides. Sharp interface solidification belongs to the phase transition problems which occur due to temperature changes, pressure, etc. Transition from one state to another is discontinuous from the mathematical point of view. Such process can be identified during water freezing, evaporation, melting and solidification of metals and alloys, etc.The influence of natural convection on the temperature distribution and the solid-liquid interface motion during solidification of pure copper is studied. The mathematical model of the process is based on the differential equat...
Industry 4.0: Trends in Management of Intelligent Manufacturing Systems, 2019
In this chapter, the analytical method of stress estimation during shielded arc surfacing has bee... more In this chapter, the analytical method of stress estimation during shielded arc surfacing has been proposed. In the temperature calculations, the direct input of the electric arc was taken into account, as well as the heat accumulated in the droplets of liquid metal carried in this arc to the padded weld. During the welding process, temperature changes are accompanied by phase transformations of heating and cooling leading to changes in the structure and mechanical properties of the material. These changes were taken into account by modeling stress-strain curves for particular structures. The theoretical considerations of the stress state in the welded element were based on the planar section hypothesis and the constitutive relationships of the linear-elastic body. The solution for thermal loaded elements was obtained using integral equations of stress equilibrium. The tensile curves for the material constituting the mixture of phase structures with consideration the temperature inf...
The welding technologies are widely used for design of protection layer against wear and corrosio... more The welding technologies are widely used for design of protection layer against wear and corrosion. Hardfacing, which is destined for obtaining coatings with high hardness, takes special place in these technologies. One of the most effective way of hardfacing is using self shielded flux cored arc welding (FCAW-S). Chemical composition obtained in flux cored wire is much more rich in comparison to this obtained in solid wire. The filling in flux cored wires can be enriched for example with the mixture of hard particles or phases with specified ratio, which is not possible for solid wires. This is the reason why flux cored wires give various possibilities of application of this kind of filler material for improving surface in mining industry, processing of minerals, energetic etc. In the present paper the high chromium and niobium flux cored wire was used for hardfacing process with similar heat input. The work presents studies of microstructures of obtained coatings and hardness and ...
In this investigation, the extensive wear behaviour of materials was studied using SiC reinforced... more In this investigation, the extensive wear behaviour of materials was studied using SiC reinforced magnesium alloy composites fabricated through the stir casting process. The wear properties of AZ91 alloy composites with a small variation (i.e., 3%, 6%, 9% and 12%) of SiC particulates were evaluated by varying the normal load with sliding velocity and sliding distance. The worn surfaces were examined by scanning electron microscope to predict the different wear mechanisms on the pin while sliding on the hard disk in the dry sliding wear test condition. The microhardness of the SiC reinforced AZ91 composites was found to be more than the un-reinforced AZ91 alloy. Pins tested at load 19.62 N, and 2.6 m/s exhibited a series of short cracks nearly perpendicular to the sliding direction. At higher speed and load, the oxidation and delamination were observed to be fully converted into adhesion wear. Abrasion, oxidation, and delamination wear mechanisms were generally dominant in lower slid...
In recent times, demand for light weight and high strength materials fabricated from natural fibr... more In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface ...
In this study, experiments are performed to study the physical and mechanical behaviour of chemic... more In this study, experiments are performed to study the physical and mechanical behaviour of chemically-treated sugarcane bagasse fibre-reinforced epoxy composite. The effect of alkali treatment, fibre varieties, and fibre lengths on physical and mechanical properties of the composites is studied. To study the morphology of the fractured composites, scanning electron microscopy is performed over fractured composite surfaces. The study found that the variety and lengths of fibres significantly influence the physical and mechanical properties of the sugarcane bagasse-reinforced composites. From the wear study, it is found that the composite fabricated from smaller fibre lengths show low wear. The chemically-treated bagasse-reinforced composites fabricated in this study show good physical and mechanical properties and are, therefore, proposed for use in applications in place of conventional natural fibres.
This study focuses on the properties and process parameters dictating behavioural aspects of fric... more This study focuses on the properties and process parameters dictating behavioural aspects of friction stir welded Aluminium Alloy AA6061 metal matrix composites reinforced with varying percentages of SiC and B4C. The joint properties in terms of mechanical strength, microstructural integrity and quality were examined. The weld reveals grain refinement and uniform distribution of reinforced particles in the joint region leading to improved strength compared to other joints of varying base material compositions. The tensile properties of the friction stir welded Al-MMCs improved after reinforcement with SiC and B4C. The maximum ultimate tensile stress was around 172.8 ± 1.9 MPa for composite with 10% SiC and 3% B4C reinforcement. The percentage elongation decreased as the percentage of SiC decreases and B4C increases. The hardness of the Al-MMCs improved considerably by adding reinforcement and subsequent thermal action during the FSW process, indicating an optimal increase as it elim...
In this work a model of temperature field in a steel cast during surfacing was presented. Analyti... more In this work a model of temperature field in a steel cast during surfacing was presented. Analytical solution for half-infinite body model was obtained by aggregating temperature increments caused by applying liquid metal and heat radiation of moving electrode. The assumptions were Gaussian distribution heat sources of applied metal and weld and of electric arc heat source. Computations of temperature field were carried out during surfacing of cuboidal steel cast. The results were presented as temporary and maximum temperature distribution in element's cross section and thermal cycles at selected points. The accuracy of solution was verified comparing calculated fusion line to that obtained experimentally. Slowa kluczowe: Surface Treatment, Temperature Field, Welding, Surfacing
The wear-resistant layers of the chromium cast iron structure can be made by traditional casting ... more The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.
The paper presents the analysis of temperature fields, phase transformations, strains and stresse... more The paper presents the analysis of temperature fields, phase transformations, strains and stresses in a cuboidal element made from S235 steel, surfaced with multipass GMA (Gas Metal Arc) method. The temperature field is described assuming a dualdistribution heat source model and summing up the temperature fields induced by the padded weld and by the electric arc. Dependence of stresses on strains is assumed on the basis of tensile curves of particular structures, taking into account the influence of temperature. The calculations were carried out on the example of five welds in the middle of the plate made of S235 steel. The simulation results are illustrated in graphs of thermal cycles, volume shares of structural components and stresses at the selected points of cross-section, and the temperature and strain distributions in the whole cross section.
In work have been presented models of temperature fields and kinetics of phase transformations in... more In work have been presented models of temperature fields and kinetics of phase transformations in continuous casting steel machine roll surfacing spiral welding sequence with swinging motion of welding head. The temperature field was determined by analytical solution for massive body heated by moving voluminal heat source. The progress of diffusional phase transformations was described basing on equation of kinetics JMA-K and Koistinen-Marburger’s for martensitic transfomation. Deliberations were illustrated by computational example of surfaced roll made from steel 13CrMo4. The temperature field and structural components fraction was calcualated in section of regenerated area of material decline (along the roll axis). Considering critical temperatures, heat-affected zones have been determined: A1 and A3 – austenitic transformation, and solidus - fusion line. Accepted technological parameters of rebuilding gave results that reproduce geometry of padding weld heat-affected zones confi...
Modelling of technological processes of heat treatment or welding, involving multiple heat source... more Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the infl uence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coeffi cients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite). The analysis of tempering time infl uence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up) in technological processes based on short-timed action of a heat source (eg. laser treatment) have been suggested.
The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium a... more The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium and carbon surfaces. In these studies selfshielded cored wire was used as a material for hardfacing. Pulsed arc is used in welding technologies to better control of transport molten metal in the welding arc and heat input. The correct heat input results in limited dilution surfaces that is very important in wear prevention technologies. The paper presents the results of research on the geometric parameters and hardness of deposited surfaces. The investigation was carried out with various welding parameters that were designed in heat source. The survey was conducted on the specimens that were subjected to metallographic examination hardness test.
A new method of calculating the amount of heat introduced into the welded joint is presented. Ins... more A new method of calculating the amount of heat introduced into the welded joint is presented. Instead of the previously used measure of heat input per unit length, heat input per unit volume was proposed. The proposed method and general formula are based on the basic technological parameters of the welding process (i.e. energy generated by the electric arc and welding speed) and the cross-sectional area of the fusion zone in the welded joint. A simplified method of calculating heat input per unit volume is presented by using simple formulas to calculate the surface area of the fusion zone in cross-section of the weld for the most common shapes in classic welding methods. The proposed general formula allows for a more accurate way of calculating the heat input per unit of volume depending on the the energy generated by the electric arc (e.g. for pulse current) and the surface area of the reinforcement and fusion zone using other direct measurement methods.
In the paper, the method of calculating the welding energy needed to regenerate parts of agricult... more In the paper, the method of calculating the welding energy needed to regenerate parts of agricultural machines by welding (joining) or surfacing (rebuilding, hardfacing) is presented. Problems with the lack of adequacy of the commonly used formula for linear welding energy to the actual amount of heat introduced into the welded joint are discussed. A volumetric approach based on the effective amount of heat generated by the electric arc introduced per unit volume of the weld was proposed. The simplified formulas for volumetric energy are presented. The considerations are illustrated with examples of calculations. The analyzed examples include the use of a computerized stand for geometric measurements of metallographic specimens. The proposed volumetric method of calculating the amount of heat introduced into the welded joint is a more realistic indicator of heat demand than linear energy. On the other hand, based on the volume of the weld (padding weld), it allows to determine the a...
Abstract In this study, we present a novel fixed-grid interface-tracking method using finite volu... more Abstract In this study, we present a novel fixed-grid interface-tracking method using finite volume method to simulate multidimensional rapid solidification (RS) of under-cooled pure metal. The discretized advection equation for solid fraction function is solved using the THINC/WLIC method, which is a VOF method. The governing equations for fluid flow are solved numerically using pressure-velocity coupling SIMPLE algorithm in a 2-D model with incompressible Newtonian fluid. The energy equation is modeled using an enthalpy-based formulation. The nonequilibrium solidification kinetics, interface tracking, undercooling, nucleation, heat transfer, and movement of liquid are included in the presented RS model.
Proceedings of the 2nd EAI International Conference on Management of Manufacturing Systems, 2018
In work the model of stress calculation and analysis of stress field during single-pass SAW (Subm... more In work the model of stress calculation and analysis of stress field during single-pass SAW (Submerged Arc Welding) surfacing have been presented. In the temperature field solution, influence heat of melted electrode and heat of direct impact of electric arc have been taken into consideration. The phase change kinetics according to the laws of Johnson-Mehl-Avrami-Kolmogorov and Koistinen-Marburger were determined. The temperatures of the beginning and the end of the changes were determined by the A c1 and A c3 temperatures during heating and on the basis of the timetemperature-transformation welding diagram for cooling. The stress state of thermal loaded flat has been described assuming planar section hypothesis and simple Hooke's law and using integral equations of stress equilibrium. The stress-strain curves were modeled as the curves of the mixture of individual material phases depending on temperature. The analysis of stress state has been presented for SAW surfacing S355 steel plate.
The paper presents the capabilities of welding techniques to creating properties of wear resistan... more The paper presents the capabilities of welding techniques to creating properties of wear resistant high chromium cast iron alloy. The use of the right kind of welding sequence allows you to change the structure and properties of the obtained welds. Tests were conducted for one type of additive material in the form of self shielded core wire. In order to determine the effect of the type of welding sequence on the properties of welds performed welding using string bead and weave bead. The resulting weld was tested on hardness and research structure in an optical microscope. In the following studies have been made erosive tests wear of made hardfacing. String beads gave structure rich in carbides and harder about 270 HV of the weld with weave bead. Also, wear resistance was nearly twice as better for welds made with string beads. In the experiment a decisive role in the resistance to wear plays a high hardness of the deposit and the presence of carbides in its structure. Changes in the...
The paper presents a model of temperature, phase transformation and stresses fields in a steel el... more The paper presents a model of temperature, phase transformation and stresses fields in a steel element during single-pass Gas Metal Arc Weld (GMAW) surfacing.Kinetics of phase transformations during heating is limited by temperature values at the beginning and at the end of austenitic transformation, while the progress of phase transformations during cooling is determined on the basis of TTT-welding diagram and Johnson-Mehl-Avrami and Kolomogorov law for diffusive transformations and Koistinen-Marburger for martensitic transformation. Stress state of a bar subjected to thermo-mechanical loads is described assuming the plane cross section hypothesis and using integral equations of stress equilibrium of a bar as well as simple Hook’s law. Stresses in the elastic-plastic state are determined by iteration using solutions with a variable elastic modulus of elasticity, conditioned by tensile curves. Dependence of stresses on strains is assumed on the basis of tensile curves of particular ...
The paper is focused on the modeling of the directional solidification process of pure metal. Dur... more The paper is focused on the modeling of the directional solidification process of pure metal. During the process the solidification front is sharp in the shape of the surface separating liquid from solid in three dimensional space or a curve in 2D. The position and shape of the solid-liquid interface change according to time. The local velocity of the interface depends on the values of heat fluxes on the solid and liquid sides. Sharp interface solidification belongs to the phase transition problems which occur due to temperature changes, pressure, etc. Transition from one state to another is discontinuous from the mathematical point of view. Such process can be identified during water freezing, evaporation, melting and solidification of metals and alloys, etc.The influence of natural convection on the temperature distribution and the solid-liquid interface motion during solidification of pure copper is studied. The mathematical model of the process is based on the differential equat...
Industry 4.0: Trends in Management of Intelligent Manufacturing Systems, 2019
In this chapter, the analytical method of stress estimation during shielded arc surfacing has bee... more In this chapter, the analytical method of stress estimation during shielded arc surfacing has been proposed. In the temperature calculations, the direct input of the electric arc was taken into account, as well as the heat accumulated in the droplets of liquid metal carried in this arc to the padded weld. During the welding process, temperature changes are accompanied by phase transformations of heating and cooling leading to changes in the structure and mechanical properties of the material. These changes were taken into account by modeling stress-strain curves for particular structures. The theoretical considerations of the stress state in the welded element were based on the planar section hypothesis and the constitutive relationships of the linear-elastic body. The solution for thermal loaded elements was obtained using integral equations of stress equilibrium. The tensile curves for the material constituting the mixture of phase structures with consideration the temperature inf...
The welding technologies are widely used for design of protection layer against wear and corrosio... more The welding technologies are widely used for design of protection layer against wear and corrosion. Hardfacing, which is destined for obtaining coatings with high hardness, takes special place in these technologies. One of the most effective way of hardfacing is using self shielded flux cored arc welding (FCAW-S). Chemical composition obtained in flux cored wire is much more rich in comparison to this obtained in solid wire. The filling in flux cored wires can be enriched for example with the mixture of hard particles or phases with specified ratio, which is not possible for solid wires. This is the reason why flux cored wires give various possibilities of application of this kind of filler material for improving surface in mining industry, processing of minerals, energetic etc. In the present paper the high chromium and niobium flux cored wire was used for hardfacing process with similar heat input. The work presents studies of microstructures of obtained coatings and hardness and ...
In this investigation, the extensive wear behaviour of materials was studied using SiC reinforced... more In this investigation, the extensive wear behaviour of materials was studied using SiC reinforced magnesium alloy composites fabricated through the stir casting process. The wear properties of AZ91 alloy composites with a small variation (i.e., 3%, 6%, 9% and 12%) of SiC particulates were evaluated by varying the normal load with sliding velocity and sliding distance. The worn surfaces were examined by scanning electron microscope to predict the different wear mechanisms on the pin while sliding on the hard disk in the dry sliding wear test condition. The microhardness of the SiC reinforced AZ91 composites was found to be more than the un-reinforced AZ91 alloy. Pins tested at load 19.62 N, and 2.6 m/s exhibited a series of short cracks nearly perpendicular to the sliding direction. At higher speed and load, the oxidation and delamination were observed to be fully converted into adhesion wear. Abrasion, oxidation, and delamination wear mechanisms were generally dominant in lower slid...
In recent times, demand for light weight and high strength materials fabricated from natural fibr... more In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface ...
In this study, experiments are performed to study the physical and mechanical behaviour of chemic... more In this study, experiments are performed to study the physical and mechanical behaviour of chemically-treated sugarcane bagasse fibre-reinforced epoxy composite. The effect of alkali treatment, fibre varieties, and fibre lengths on physical and mechanical properties of the composites is studied. To study the morphology of the fractured composites, scanning electron microscopy is performed over fractured composite surfaces. The study found that the variety and lengths of fibres significantly influence the physical and mechanical properties of the sugarcane bagasse-reinforced composites. From the wear study, it is found that the composite fabricated from smaller fibre lengths show low wear. The chemically-treated bagasse-reinforced composites fabricated in this study show good physical and mechanical properties and are, therefore, proposed for use in applications in place of conventional natural fibres.
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Papers by Jerzy Winczek