tarik tewfic - Academia.edu (original) (raw)

Papers by tarik tewfic

Research paper thumbnail of Identifying and Prioritising Future Robot Control Research with Multi-Criteria Decision-Making

Research paper thumbnail of Automated assemly of large composite preforms for reinforcement applications in aerostructures

Research paper thumbnail of <title>Novel folding device for manufacturing aerospace composite structures</title>

Intelligent Systems in Design and Manufacturing III, 2000

Research paper thumbnail of Experimental Investigations towards Optimization of the Parameters for Wear Loss Quantities in A356/Al2O3 Nanocomposites

Metal matrix composites (MMCs) reinforced with nano-particles which called Nanocomposites (MMNCs)... more Metal matrix composites (MMCs) reinforced with nano-particles which called Nanocomposites (MMNCs), are extensively studied in the recent years. Nanocomposites present high strength, wear resistance, hardness and exceptional microstructure stability. The nano-particles can improve the base material in terms of wear resistance, damping properties and mechanical strength. In this paper the tribological behavior of A356/Al 2 O 3 nanocomposites were investigated at room temperatures under dry sliding conditions. The results showed that the wear rate of the A356 alloy was significantly improved by the addition of the Al 2 O 3 nano-particles. The wear rate of the nanocomposites was reduced to about 25% (for nanocomposites containing 5 vol.-% of nano-particles) of the wear rate of the A356 mono-lithic alloy.

Research paper thumbnail of Study the influence of a new ball burnishing technique on the surface roughness of AISI 1018 low carbon steel

International Journal of Engineering & Technology, 2014

Hard roller burnishing with a ball tool is a surface-finishing where a free-rotating tool rolls o... more Hard roller burnishing with a ball tool is a surface-finishing where a free-rotating tool rolls over the machined surface under high pressures and flattens the surface roughness peaks by cold work. In the present work, a new burnishing technique has been applied which enables both single and double ball burnishing process in site after turning without releasing the specimen. Sets of experiments are conducted to investigate the influence of burnishing force, feed, speed and number of tool passes on surface roughness of AISI 1018 Low Carbon Steel specimens. Burnishing results showed significant effectiveness of the new burnishing technique in the process. The results revealed that minimum surface roughness are obtained by applying the double ball burnishing process on AISI 1018 Low Carbon Steel specimens. Improvement in surface finish can be achieved in both single and double ball burnishing by increasing the number of burnishing tool passes. The results are presented in this paper.

Research paper thumbnail of Study the Influence of Gas Metal Arc Welding Parameters on the Weld Metal and Heat Affected Zone Microstructures of Low Carbon Steel

International Journal of Engineering and Technology

The Heat-Affected Zone (HAZ) is the region of base metal which has its microstructure altered by ... more The Heat-Affected Zone (HAZ) is the region of base metal which has its microstructure altered by welding. Microstructural changes affect the composition of the weldment and need to be controlled since the weld failures are directly related to the microstructure of the Heat affected Zone. This paper is focused on the study of the Gas Metal Arc Welding (GMAW) parameters on the Heat Affected and Weld metal Zone microstructures of industrial low carbon steel (0.20 % C). In order to achieve the aim of the paper, Scan Electron Microscope photos have been used at the Heat Affected and weld metal Zones, some phases are identified. Microstructural analyses of the experimental results of the welded joints confirmed that the welding parameters and heat input are affected the weldment structure in terms of the grain types and character of the structural phase. Keyword-GMAW, HAZ, WM, Wire feed rate, Microstructure. I. INTRODUCTION Gas Metal Arc Welding (GMAW) process is a relatively complex process, but is widely used in industry because of the speed at which joints can be made and the reliability of these joints in service. Microstructure control is crucial to weld quality and prevention of weld failures. The development of techniques to more effectively control microstructure created during welding will have a significant positive impact on product cost and quality [1]-[4]. In a pass of the welding torch material is rapidly heated to the maximum temperature and allowed to cool more slowly by conduction of heat into the bulk of the parent metal. Phase changes can occur depending on the temperature reached. The region next to the fusion zone where microstructural changes have occurred is known as the heat affected zone. Such microstructural changes may affect the mechanical properties of the weld and need to be controlled (e.g. brittle martensite formation) [5]-[7]. In the welding of steels the chemical composition of the base material is directly affected the final structures and mechanical properties of the welded joint. Carbon percentage play a lead role in the ability of welding, low carbon steels exhibited a good welding ability, since they can be generally welded without special precautions using most of the available processes [8]-[10]. Several studies have been conducted to investigate the mechanical behavior and phase transformation of the welded steel joints. Reference [11] presented the effect of heat input on the microstructure and mechanical properties of the heat affected zone of duplex steel. He studied the effect of the heat input on the microstructural changes and the impact properties. Grain growth mechanism of steel welded joint has been investigated as in [12] it has been noticed that the presence of very large grains close to the fusion line and they are oriented along the directions of the heat flow. The present wok aims to study the effect of Gas Metal Arc Welding parameters(interpass temperatures, welding voltage, wire feed Rate and welding speeds) on the Heat Affected Zone (HAZ) and Weld Metal (WM) microstructures of industrial low carbon steel (0.23 % C). II. EXPERIMENTAL WORK 2.1Material The Base Metal used in the experiment was carbon steel (St.52-3N).According to the Egyptian Iron and Steel Co[13].The chemical compositions of the base metal was 0.23 C%, 1.70Mn%,0.60Si%, 0.045P%,0.045S% and 0.011N%. And the mechanical properties was 610N/mm² Tensile Strength, 460 N/mm² Upper Yield Point, 22% elongation and the Vickers hardness is 190 HV. The wire chemical compositions %According to the ESAB Welding Handbook [14]. Was 0.10.23 C%, 1.50 Mn%,0.85Si%. And the mechanical properties was 630N/mm² Tensile Strength, 470 N/mm² r Yield stress ,25% elongation and the Vickers hardness is 200 HV.

Research paper thumbnail of Modeling and experimental analysis of wheel-work interface in the cylindrical plunge grinding process

International Journal of Engineering & Technology, 2014

This paper presents a study of grinding wheel-workpiece interference in external cylindrical plun... more This paper presents a study of grinding wheel-workpiece interference in external cylindrical plunge grinding processes. This is to study the effect of workpiece surface memory on the workpiece roundness error after grinding. The study has been carried out theoretically on a model simulating cylindrical grinding process. The model takes contact stiffness, grinding wheel and workpiece wear into consideration. The proposed model was sued to predict the normal grinding forces in cylindrical grinding as a function of the previous height and number of waves of the initial profile.The new model has been validated by conducting experiments on a cylindrical grinding machine. Results indicate that the proposed model shows a good agreement with the experimental data obtained.The results of experiments indicate that the proposed modeling method is both feasible and reliable. The results showed that the theoretical model was effective studying the output of cylindrical grinding process. Normal g...

Research paper thumbnail of Identifying and Prioritising Future Robot Control Research with Multi-Criteria Decision-Making

Research paper thumbnail of Automated assemly of large composite preforms for reinforcement applications in aerostructures

Research paper thumbnail of <title>Novel folding device for manufacturing aerospace composite structures</title>

Intelligent Systems in Design and Manufacturing III, 2000

Research paper thumbnail of Experimental Investigations towards Optimization of the Parameters for Wear Loss Quantities in A356/Al2O3 Nanocomposites

Metal matrix composites (MMCs) reinforced with nano-particles which called Nanocomposites (MMNCs)... more Metal matrix composites (MMCs) reinforced with nano-particles which called Nanocomposites (MMNCs), are extensively studied in the recent years. Nanocomposites present high strength, wear resistance, hardness and exceptional microstructure stability. The nano-particles can improve the base material in terms of wear resistance, damping properties and mechanical strength. In this paper the tribological behavior of A356/Al 2 O 3 nanocomposites were investigated at room temperatures under dry sliding conditions. The results showed that the wear rate of the A356 alloy was significantly improved by the addition of the Al 2 O 3 nano-particles. The wear rate of the nanocomposites was reduced to about 25% (for nanocomposites containing 5 vol.-% of nano-particles) of the wear rate of the A356 mono-lithic alloy.

Research paper thumbnail of Study the influence of a new ball burnishing technique on the surface roughness of AISI 1018 low carbon steel

International Journal of Engineering & Technology, 2014

Hard roller burnishing with a ball tool is a surface-finishing where a free-rotating tool rolls o... more Hard roller burnishing with a ball tool is a surface-finishing where a free-rotating tool rolls over the machined surface under high pressures and flattens the surface roughness peaks by cold work. In the present work, a new burnishing technique has been applied which enables both single and double ball burnishing process in site after turning without releasing the specimen. Sets of experiments are conducted to investigate the influence of burnishing force, feed, speed and number of tool passes on surface roughness of AISI 1018 Low Carbon Steel specimens. Burnishing results showed significant effectiveness of the new burnishing technique in the process. The results revealed that minimum surface roughness are obtained by applying the double ball burnishing process on AISI 1018 Low Carbon Steel specimens. Improvement in surface finish can be achieved in both single and double ball burnishing by increasing the number of burnishing tool passes. The results are presented in this paper.

Research paper thumbnail of Study the Influence of Gas Metal Arc Welding Parameters on the Weld Metal and Heat Affected Zone Microstructures of Low Carbon Steel

International Journal of Engineering and Technology

The Heat-Affected Zone (HAZ) is the region of base metal which has its microstructure altered by ... more The Heat-Affected Zone (HAZ) is the region of base metal which has its microstructure altered by welding. Microstructural changes affect the composition of the weldment and need to be controlled since the weld failures are directly related to the microstructure of the Heat affected Zone. This paper is focused on the study of the Gas Metal Arc Welding (GMAW) parameters on the Heat Affected and Weld metal Zone microstructures of industrial low carbon steel (0.20 % C). In order to achieve the aim of the paper, Scan Electron Microscope photos have been used at the Heat Affected and weld metal Zones, some phases are identified. Microstructural analyses of the experimental results of the welded joints confirmed that the welding parameters and heat input are affected the weldment structure in terms of the grain types and character of the structural phase. Keyword-GMAW, HAZ, WM, Wire feed rate, Microstructure. I. INTRODUCTION Gas Metal Arc Welding (GMAW) process is a relatively complex process, but is widely used in industry because of the speed at which joints can be made and the reliability of these joints in service. Microstructure control is crucial to weld quality and prevention of weld failures. The development of techniques to more effectively control microstructure created during welding will have a significant positive impact on product cost and quality [1]-[4]. In a pass of the welding torch material is rapidly heated to the maximum temperature and allowed to cool more slowly by conduction of heat into the bulk of the parent metal. Phase changes can occur depending on the temperature reached. The region next to the fusion zone where microstructural changes have occurred is known as the heat affected zone. Such microstructural changes may affect the mechanical properties of the weld and need to be controlled (e.g. brittle martensite formation) [5]-[7]. In the welding of steels the chemical composition of the base material is directly affected the final structures and mechanical properties of the welded joint. Carbon percentage play a lead role in the ability of welding, low carbon steels exhibited a good welding ability, since they can be generally welded without special precautions using most of the available processes [8]-[10]. Several studies have been conducted to investigate the mechanical behavior and phase transformation of the welded steel joints. Reference [11] presented the effect of heat input on the microstructure and mechanical properties of the heat affected zone of duplex steel. He studied the effect of the heat input on the microstructural changes and the impact properties. Grain growth mechanism of steel welded joint has been investigated as in [12] it has been noticed that the presence of very large grains close to the fusion line and they are oriented along the directions of the heat flow. The present wok aims to study the effect of Gas Metal Arc Welding parameters(interpass temperatures, welding voltage, wire feed Rate and welding speeds) on the Heat Affected Zone (HAZ) and Weld Metal (WM) microstructures of industrial low carbon steel (0.23 % C). II. EXPERIMENTAL WORK 2.1Material The Base Metal used in the experiment was carbon steel (St.52-3N).According to the Egyptian Iron and Steel Co[13].The chemical compositions of the base metal was 0.23 C%, 1.70Mn%,0.60Si%, 0.045P%,0.045S% and 0.011N%. And the mechanical properties was 610N/mm² Tensile Strength, 460 N/mm² Upper Yield Point, 22% elongation and the Vickers hardness is 190 HV. The wire chemical compositions %According to the ESAB Welding Handbook [14]. Was 0.10.23 C%, 1.50 Mn%,0.85Si%. And the mechanical properties was 630N/mm² Tensile Strength, 470 N/mm² r Yield stress ,25% elongation and the Vickers hardness is 200 HV.

Research paper thumbnail of Modeling and experimental analysis of wheel-work interface in the cylindrical plunge grinding process

International Journal of Engineering & Technology, 2014

This paper presents a study of grinding wheel-workpiece interference in external cylindrical plun... more This paper presents a study of grinding wheel-workpiece interference in external cylindrical plunge grinding processes. This is to study the effect of workpiece surface memory on the workpiece roundness error after grinding. The study has been carried out theoretically on a model simulating cylindrical grinding process. The model takes contact stiffness, grinding wheel and workpiece wear into consideration. The proposed model was sued to predict the normal grinding forces in cylindrical grinding as a function of the previous height and number of waves of the initial profile.The new model has been validated by conducting experiments on a cylindrical grinding machine. Results indicate that the proposed model shows a good agreement with the experimental data obtained.The results of experiments indicate that the proposed modeling method is both feasible and reliable. The results showed that the theoretical model was effective studying the output of cylindrical grinding process. Normal g...