This document summarizes research into flaws that can occur in friction stir welds when parameters are outside established tolerances. Three main flaw types are discussed: voids, root flaws, and joint line remnants. Voids were generated when forging pressure was insufficient or welding speed too high. Root flaws occurred with shortened pins or high speeds. Joint line remnants resulted from oxide inclusions when anodized surfaces were welded. Non-destructive testing and metallography were used to characterize flaws and understand their causes in order to prevent occurrence.
Wear Analysis of Tool in Milling YTL7D SteelIJRES Journal
In the process of milling die steel YTL7D, the properties of high hardness and high wear resistance of
the workpiece material led to that the tool Subjected to severe wear, and the life of the tool is lower. In this
research, the wear law of rake face and flank face of the ball end mill was discussed. And the tool wear
mechanism in the process of milling YTL7D steel is revealed in this paper, to provide a theoretical guidance for
the development of rational process and follow-up studies.
This document summarizes recent developments in friction stir welding of aluminum alloys. Friction stir welding is a solid-state welding technique developed for joining difficult-to-weld aluminum alloys. It has been implemented commercially in industries like shipbuilding, train manufacturing, and aviation. The document reviews the microstructures and mechanical properties of friction stir welded aluminum alloys and how weld parameters influence these properties. It also discusses developments in friction stir welding tool designs and applications of the technique beyond aluminum alloys.
Fatigue Performance in Grinding and Turning: An OverviewIJMER
This paper analysis the influence of Abrasive Flow Machining (AFM), Turning and Grinding on
fatigue performance of Fe250. Surface condition has a strong effect on fatigue life, and that most surfaces
produced by conventional manufacturing operations such as machining and forging have poor fatigue
behavior than polished surfaces commonly used for laboratory specimens. It is found that the surfaces
produced with different machining process and having the same surface roughness having different fatigue
performances. High –cycle fatigue data was obtained for Fe 250 using three types of machining process
viz, AFM, Turning and Grinding .S-N curve is plotted for the samples obtained with all the three process. It
was found that the samples produced with AFM having the highest fatigue life.
Metal sheet forming, its types & operationsUmair Raza
The document discusses various methods of sheet metal forming processes. It introduces stretching, shearing, blanking, bending, deep drawing, and redrawing. It then discusses variables in sheet forming processes and defects that can occur. The document provides classifications of sheet metal parts and describes various forming equipment and machines used. It also details different types of sheet metal forming processes like curling, bending, ironing, laser cutting, hydroforming, punching, progressive forming, rubber hydroforming, spinning, explosive forming, and stretching and deep drawing.
This document summarizes a study on the formability of various Indian stainless steel sheets formed under different stress conditions. Experimental work was conducted to determine the forming limit diagrams, microstructures, tensile properties, crystallographic textures and void characteristics of SS301, SS304, SS409M, SS430 and SSLN1 steel grades. Micrographs showed SS304 has a mixed grain structure while SS301 has coarse grains with carbides. Forming limit diagrams were plotted from strain measurements. Texture analysis was performed using X-ray diffraction. Void size, shape and spacing were analyzed from SEM images. Properties including yield strength, elongation and strain hardening exponent were calculated and correlated with formability.
A STUDY ON FRICTION STIR WELDING OF VARIOUS ALUMINIUM ALLOYSIJARIIT
The comprehensive body of knowledge that has built up with respect to the friction stir welding (FSW) of aluminum alloys since the technique was invented in 1991 is reviewed on this paper. The basic principles of FSW are described, including metal flow and thermal history, before discussing how process parameters affect the weld microstructure and the likelihood of defects. Finally, the range of mechanical properties that can be achieved is discussed. It is demonstrated that FSW of aluminum is becoming an increasingly mature technology with numerous commercial applications. Keywords - Friction stir welding, metal flow, process parameters, mechanical properties
Tool wear and inclusion behaviour during turning of a calcium treated quenc...Lepuufu
1. The document analyzes tool wear and inclusion behavior during turning of a calcium-treated steel using coated carbide tools.
2. It finds that inclusions like MnS, mixed sulphides (Mn,Ca)S, and duplex calcium aluminates deform significantly in the flow zone near the tool. MnS deforms the most while mixed sulphides deform less.
3. The behavior and deformation of inclusions in the flow zone influences tool wear and formation of protective layers on the tool surface. Certain inclusions like mixed sulphides are more likely to form protective layers due to their deformation characteristics.
Ahmed ibrahim razooqi -- study the microstructure and mechanical properties ...ahmed Ibrahim
Ahmed Ibrahim Razooqi ---
Study the microstructure and mechanical properties of dissimilar friction stir spot welding of carbon steel 1006 to aluminum alloy aa2024-t3.
Friction stir spot welding-FSSW has been suggested as effectual process to welding difficult materials such as dissimilar materials and
thin sheet of metal alloys. In this study, using dissimilar materials were welded carbon steel-1006 on upper plate and aluminum alloy
AA2024-T3 on lower plate. Macrostructure, micro-structural analysis and mechanical properties of the joints are done. The effect of
penetration depth, dwell time and spindle speed on tensile shear load are investigated with invariable of other parameter during welding
process. The maximum tensile shear load (3.31KN) was occurred when using 0.4mm of penetration depth, 10 sec of dwell time and 1400
rpm of spindle speed. Also, two type of failure shape was observed interfacial fracture of carbon steel sheet and pull -out fracture of
AA2024-T3 sheet.
Wear Analysis of Tool in Milling YTL7D SteelIJRES Journal
In the process of milling die steel YTL7D, the properties of high hardness and high wear resistance of
the workpiece material led to that the tool Subjected to severe wear, and the life of the tool is lower. In this
research, the wear law of rake face and flank face of the ball end mill was discussed. And the tool wear
mechanism in the process of milling YTL7D steel is revealed in this paper, to provide a theoretical guidance for
the development of rational process and follow-up studies.
This document summarizes recent developments in friction stir welding of aluminum alloys. Friction stir welding is a solid-state welding technique developed for joining difficult-to-weld aluminum alloys. It has been implemented commercially in industries like shipbuilding, train manufacturing, and aviation. The document reviews the microstructures and mechanical properties of friction stir welded aluminum alloys and how weld parameters influence these properties. It also discusses developments in friction stir welding tool designs and applications of the technique beyond aluminum alloys.
Fatigue Performance in Grinding and Turning: An OverviewIJMER
This paper analysis the influence of Abrasive Flow Machining (AFM), Turning and Grinding on
fatigue performance of Fe250. Surface condition has a strong effect on fatigue life, and that most surfaces
produced by conventional manufacturing operations such as machining and forging have poor fatigue
behavior than polished surfaces commonly used for laboratory specimens. It is found that the surfaces
produced with different machining process and having the same surface roughness having different fatigue
performances. High –cycle fatigue data was obtained for Fe 250 using three types of machining process
viz, AFM, Turning and Grinding .S-N curve is plotted for the samples obtained with all the three process. It
was found that the samples produced with AFM having the highest fatigue life.
Metal sheet forming, its types & operationsUmair Raza
The document discusses various methods of sheet metal forming processes. It introduces stretching, shearing, blanking, bending, deep drawing, and redrawing. It then discusses variables in sheet forming processes and defects that can occur. The document provides classifications of sheet metal parts and describes various forming equipment and machines used. It also details different types of sheet metal forming processes like curling, bending, ironing, laser cutting, hydroforming, punching, progressive forming, rubber hydroforming, spinning, explosive forming, and stretching and deep drawing.
This document summarizes a study on the formability of various Indian stainless steel sheets formed under different stress conditions. Experimental work was conducted to determine the forming limit diagrams, microstructures, tensile properties, crystallographic textures and void characteristics of SS301, SS304, SS409M, SS430 and SSLN1 steel grades. Micrographs showed SS304 has a mixed grain structure while SS301 has coarse grains with carbides. Forming limit diagrams were plotted from strain measurements. Texture analysis was performed using X-ray diffraction. Void size, shape and spacing were analyzed from SEM images. Properties including yield strength, elongation and strain hardening exponent were calculated and correlated with formability.
A STUDY ON FRICTION STIR WELDING OF VARIOUS ALUMINIUM ALLOYSIJARIIT
The comprehensive body of knowledge that has built up with respect to the friction stir welding (FSW) of aluminum alloys since the technique was invented in 1991 is reviewed on this paper. The basic principles of FSW are described, including metal flow and thermal history, before discussing how process parameters affect the weld microstructure and the likelihood of defects. Finally, the range of mechanical properties that can be achieved is discussed. It is demonstrated that FSW of aluminum is becoming an increasingly mature technology with numerous commercial applications. Keywords - Friction stir welding, metal flow, process parameters, mechanical properties
Tool wear and inclusion behaviour during turning of a calcium treated quenc...Lepuufu
1. The document analyzes tool wear and inclusion behavior during turning of a calcium-treated steel using coated carbide tools.
2. It finds that inclusions like MnS, mixed sulphides (Mn,Ca)S, and duplex calcium aluminates deform significantly in the flow zone near the tool. MnS deforms the most while mixed sulphides deform less.
3. The behavior and deformation of inclusions in the flow zone influences tool wear and formation of protective layers on the tool surface. Certain inclusions like mixed sulphides are more likely to form protective layers due to their deformation characteristics.
Ahmed ibrahim razooqi -- study the microstructure and mechanical properties ...ahmed Ibrahim
Ahmed Ibrahim Razooqi ---
Study the microstructure and mechanical properties of dissimilar friction stir spot welding of carbon steel 1006 to aluminum alloy aa2024-t3.
Friction stir spot welding-FSSW has been suggested as effectual process to welding difficult materials such as dissimilar materials and
thin sheet of metal alloys. In this study, using dissimilar materials were welded carbon steel-1006 on upper plate and aluminum alloy
AA2024-T3 on lower plate. Macrostructure, micro-structural analysis and mechanical properties of the joints are done. The effect of
penetration depth, dwell time and spindle speed on tensile shear load are investigated with invariable of other parameter during welding
process. The maximum tensile shear load (3.31KN) was occurred when using 0.4mm of penetration depth, 10 sec of dwell time and 1400
rpm of spindle speed. Also, two type of failure shape was observed interfacial fracture of carbon steel sheet and pull -out fracture of
AA2024-T3 sheet.
Effect of welding parameters and tool shape on properties of friction stir we...IJERA Editor
Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. It has many benefits when applied to welding of aluminum alloys. FSW process parameters such as welding speed, rotational speed and tool geometry play vital roles in the weld quality. The aim of this research is to investigate the effects of different welding speeds, rotational speeds and tool pin profile on the weld quality of a AA6061 aluminum alloy. A friction stir welding tool consists of rotating shoulder and pin that heats the working piece by friction and moves a softened alloy around it to form a joint. In this research work the effect of the tool shape and welding parameters (rotating speed and welding speed) on the mechanical properties of an aluminium plates will be investigated experimentally. The induced heat during the welding process played the main role in the mechanical and appearance of the joints, which is related to the welding parameters.
Friction stir welding process parameters forsabry said
1) Friction stir welding is a solid-state welding process that joins materials without melting them. In FSW, a non-consumable tool is used to generate frictional heat and plasticize the materials being joined.
2) The document focuses on evaluating the mechanical properties and predicting the process parameters of friction stir welding for joining dissimilar aluminum alloys, specifically a 6xxx alloy and 7xxx alloy.
3) Key factors that determine weld quality are welding parameters like rotational speed and welding speed, as well as tool geometry. Proper selection of parameters and tool design can improve weld quality.
Experimental Investigation of Friction Stir Welding Of Aluminum Aa6061 Alloy ...iosrjce
The combination of wrought aluminum-magnesium-silicon alloy confirming to aluminum AA6061
alloy widely accepted because of light weight fabrication structures, high strength to weight ratio and good
corrosion resistance. Friction Stir Welding(FSW) process is an emerging solid state joining process in which
the material that is being welded does not melt and recast when compared to fusion welding process that are
routinely used for joining structural aluminum alloys. In this FSW process a non consumable tool is used to
generate frictional heat in the abutting surfaces. Experiments for surface roughness, Rockwell hardness and
tensile tests are carried out and reported in this paper. The base material used for friction stir welding is
aluminum AA 6061 alloy. Surface roughness values decreases with the increase in speed of the tool and also
there exists an optimum speed to have the good surface finish. Hardness increases with decrease in speed of the
tool but increases after reaching a certain value. Tensile strength increases with the increase in speed of the
tool and also there exists an optimum values for particular feed of the tool.
This document summarizes research on the metallurgical behavior of AISI 304 steel butt welds under segregation. It discusses how solidification, microstructure development, and alloying element segregation influence properties. Rapid solidification during welding can result in fully austenitic or ferritic microstructures instead of duplex ones. Segregation of elements like chromium and molybdenum occurs due to the formation of dendrites and concentration gradients. This can lead to the precipitation of brittle intermetallic phases and cracking in the weld metal. The document analyzes the solidification modes, microstructures, segregation ratios, and mechanical effects for AISI 304 steel welds.
The document summarizes research on the friction and wear of metals under micro-abrasion and dry/wet sliding conditions. It includes an introduction describing the research objectives to characterize coefficient of friction (CoF) and wear rates of metals under different wear modes. The experimental procedure used a micro-abrasion tester to apply loads to metal samples in contact with a rotating steel ball under various conditions to produce different wear modes. Results found that pure rolling abrasion generated the highest wear rates while dry sliding abrasion produced the lowest wear rates and CoFs. The research concluded the tester was useful for evaluating CoF under different tribological pairs and conditions.
Surface condition impacts part performancweDave Davidson
1) Surface finish and the presence of burrs on aircraft and aircraft engine parts can significantly impact part performance and lifespan by increasing stresses, corrosion, and reducing sealing abilities.
2) Specialized finishing processes are used to remove burrs, round edges, and optimize surface texture in ways that reduce stresses, improve fatigue life, enhance corrosion resistance, and improve sealing of joints.
3) Paying close attention to edge and surface quality is important in aerospace applications due to the potential for catastrophic failure if surfaces are improperly finished or contain defects.
This document summarizes Mitchell Smith's undergraduate research project on friction stir welding of similar and dissimilar metal alloys. Smith conducted trial welds of aluminum alloys to understand the friction stir welding process and machine settings. Welds were made of similar aluminum alloys and dissimilar aluminum-copper alloys. Challenges included preventing separation of metal pieces during welding. Further tests are needed to characterize the welds and properties of the welded metals, including microstructural analysis, tensile tests, and impact tests. Continued research on welding nano-reinforced metals could expand applications of friction stir welding in fields like nuclear engineering.
Friction Stir Welding of Magnesium Alloys - A Reviewmsejjournal
The selection of proper material for each application is a critical part in every manufacturing industry.
In the field of aerospace and automobile the major requirement is light weight yet strong material which
can possess every aspect of design parameters. Magnesium alloy one of the major raw material used in
these industries due to its light weight, good thermal conductivity etc. Also Friction stir welding is the
joining process that is being used in these industries as it is a solid state joining process. This paper
gives a detailed review about Friction Stir welding of Mg alloys. The review period is considered from
2009 to 2015.A detailed review about Friction stir welding of Mg alloys has not been done before in this
manner. This review work may be a ready reference for subsequent researchers.
Effects and defects of the polypropylene plate for different parameters in fr...eSAT Publishing House
1. The document analyzes the effects of different parameters on friction stir welding of polypropylene plates, including tool pin profile, rotational speed, and welding speed.
2. Microstructural images and hardness tests were used to evaluate the quality of the welds under different conditions.
3. The results showed that a threaded pin profile with rotational speed of 2250 rpm and welding speed of 40-50 mm/min produced welds with the fewest defects in the polypropylene material.
Effect of tool offset and tilt angle on weld strength of butt joint friction ...Alexander Decker
This document discusses an experiment investigating the effect of tool offset and tilt angle on the weld strength of friction stir welded butt joints between AA2024 aluminum alloy and copper. Specimens were welded using a tool with 2 degree tilt and various pin offsets. Tensile testing showed specimens welded with 1 mm pin offset and 2 degree tilt had the highest strength. Microstructure analysis revealed intercalated aluminum and copper pieces in the weld nugget, as well as copper hooks providing strength. Welding with tilt improved strength by removing voids compared to zero tilt.
Influence of design parameters in weld joint performanceIAEME Publication
1) A flange connection in an oil and gas pipeline failed prematurely due to cracking. Investigation found the failure was likely caused by recently grinding the nipple wall thinner to fit the flange, which reduced strength and increased stresses.
2) Welding also caused a brittle microstructure making the material vulnerable to cracking. Sulfur levels near the crack were twice as high as the bulk material further away, indicating sulfur embrittlement contributed to failure.
3) Design factors like reducing wall thickness and welding accelerated failure by increasing stresses and embrittling the material through higher sulfur levels and microstructure changes.
This document summarizes friction stir welding (FSW), including its working principle, microstructure analysis, tool design, process parameters, advantages, challenges, and applications. FSW is a solid state welding technique that uses a rotating tool to generate frictional heat and mechanically deform aluminum alloys below their melting point. It produces high quality welds with improved mechanical properties compared to fusion welding. Main applications are in shipbuilding, aerospace, and automotive industries.
Modeling and Simulation of Base Plate of Friction Stir Welding-Advanced Weldi...ijsrd.com
Friction stir processing is an emerging technique based on the principles of friction stir welding (FSW). It is a solid-state joining method that is energy efficient, environmentally friendly, and versatile. It is considered by many to be the most significant development in metal joining in a decade. The basic concept of friction stir processing is remarkably simple. A rotating tool with pin and shoulder is inserted in the material to be joined, and traversed along the line of interest. The heating is localized, and is generated by friction between the tool and the work piece, with additional adiabatic heating from metal deformation. A processed zone is produced by movement of material from the front of the pin to the back of the pin.
The document reviews friction stir welding (FSW), a solid-state welding technique. It discusses FSW's advantages over fusion welding in avoiding issues like porosity and cracking. The document then summarizes several studies on FSW of titanium and other alloys, examining effects of parameters like rotational speed on microstructure and properties of the welds. It investigates FSW of titanium to steel and aluminum to titanium, describing interfacial structures formed under different welding conditions.
This document discusses selecting materials for punching and forming tools. It describes the different stresses that tools experience during operations like cutting, cold forming, deep drawing, bending, and rolling. It emphasizes the importance of choosing a material suitable for the intended purpose that balances properties like hardness, wear resistance, compression strength, and toughness. Cold-work tool steels are commonly used and can be non-alloyed or alloyed with carbide-forming elements like chromium, molybdenum, and vanadium to improve properties. High-speed tool steels are also used due to their high wear resistance and hardness at high temperatures.
The document summarizes an experimental analysis of weld strength in friction stir welding of different grades of aluminum alloy using different tool geometries. Specifically, it analyzes welding 6061, 7005, and 8011 aluminum alloys with a cylindrical tool and tapered threaded tool. Tensile testing found that the tapered threaded tool produced stronger welds across all aluminum grades compared to the cylindrical tool, with strengths increasing up to 30%. This is because the threaded tool generates more friction and distributes the metal more evenly in the weld zone. Visual analysis also found the threaded tool produced better surface finish quality than the cylindrical tool.
FRICTION STIR WELDING OF ALUMINIUM ALLOYS - A REVIEWIAEME Publication
This welding is a novel process used to join metallic alloys. Friction stir welding is in vogue in aerospace, automotive and other industrial establishments for connecting alloys like aluminum, magnesium and copper. Rotational speed, welding speed and the angle of attack are important in the process of FSW. They analyze the weld quality. FSW produces stronger weld joint then the original material in selected parameters. FSW is a solid-state process, where metal is not melted uses a cylindrical shouldered tool with a profiled pin rotated and gradually plunged into the weld joint between two metal parts of plate or sheet that are to be welded together.
Influence of Elastic Deformations on the Adhesion of the ZRN Coating on the C...ijtsrd
Clinching is a mechanical joining method. Is it utilized in automobile industry as an alternative method to resistance spot welding. Considering that various types of materials are joined in car body production, PVD coatings are used to increase the lifetime of the clinching tools. Hot dip galvanized steel sheets were used for joining by clinching method. The zirconium nitride ZrN PVD coating was deposited on the surfaces of clinching tool. The loss of cohesion properties of coating was observed at punch´s R0.2 radius after 300 clinched joints. FEM analysis was used to show the punch´s critical part when the tool is under load. LuboÅ¡ KaÅ¡c¡k | Renâ Kubk "Influence of Elastic Deformations on the Adhesion of the ZRN Coating on the Clinching Tool" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29856.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/29856/influence-of-elastic-deformations-on-the-adhesion-of-the-zrn-coating-on-the-clinching-tool/lubo%C5%A1-ka%C5%A1c%C3%A1k
Scrum Takımlarının Büyüklüğünün Takım Başarısına EtkisiYasemin CIRT
Bu rapor Yasemin CIRT tarafından "Scrum Takımlarının Büyüklüğünün Takım Başarısına Etkisi" konulu lisans bitirme tezi kapsamında hazırlanmıştır. Rapora dahil edilen veriler İstanbul'da bulunan 40 Scrum takımının Scrum Master'ları tarafından değerlendirilmesi ile elde edilmiştir.
Effect of welding parameters and tool shape on properties of friction stir we...IJERA Editor
Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. It has many benefits when applied to welding of aluminum alloys. FSW process parameters such as welding speed, rotational speed and tool geometry play vital roles in the weld quality. The aim of this research is to investigate the effects of different welding speeds, rotational speeds and tool pin profile on the weld quality of a AA6061 aluminum alloy. A friction stir welding tool consists of rotating shoulder and pin that heats the working piece by friction and moves a softened alloy around it to form a joint. In this research work the effect of the tool shape and welding parameters (rotating speed and welding speed) on the mechanical properties of an aluminium plates will be investigated experimentally. The induced heat during the welding process played the main role in the mechanical and appearance of the joints, which is related to the welding parameters.
Friction stir welding process parameters forsabry said
1) Friction stir welding is a solid-state welding process that joins materials without melting them. In FSW, a non-consumable tool is used to generate frictional heat and plasticize the materials being joined.
2) The document focuses on evaluating the mechanical properties and predicting the process parameters of friction stir welding for joining dissimilar aluminum alloys, specifically a 6xxx alloy and 7xxx alloy.
3) Key factors that determine weld quality are welding parameters like rotational speed and welding speed, as well as tool geometry. Proper selection of parameters and tool design can improve weld quality.
Experimental Investigation of Friction Stir Welding Of Aluminum Aa6061 Alloy ...iosrjce
The combination of wrought aluminum-magnesium-silicon alloy confirming to aluminum AA6061
alloy widely accepted because of light weight fabrication structures, high strength to weight ratio and good
corrosion resistance. Friction Stir Welding(FSW) process is an emerging solid state joining process in which
the material that is being welded does not melt and recast when compared to fusion welding process that are
routinely used for joining structural aluminum alloys. In this FSW process a non consumable tool is used to
generate frictional heat in the abutting surfaces. Experiments for surface roughness, Rockwell hardness and
tensile tests are carried out and reported in this paper. The base material used for friction stir welding is
aluminum AA 6061 alloy. Surface roughness values decreases with the increase in speed of the tool and also
there exists an optimum speed to have the good surface finish. Hardness increases with decrease in speed of the
tool but increases after reaching a certain value. Tensile strength increases with the increase in speed of the
tool and also there exists an optimum values for particular feed of the tool.
This document summarizes research on the metallurgical behavior of AISI 304 steel butt welds under segregation. It discusses how solidification, microstructure development, and alloying element segregation influence properties. Rapid solidification during welding can result in fully austenitic or ferritic microstructures instead of duplex ones. Segregation of elements like chromium and molybdenum occurs due to the formation of dendrites and concentration gradients. This can lead to the precipitation of brittle intermetallic phases and cracking in the weld metal. The document analyzes the solidification modes, microstructures, segregation ratios, and mechanical effects for AISI 304 steel welds.
The document summarizes research on the friction and wear of metals under micro-abrasion and dry/wet sliding conditions. It includes an introduction describing the research objectives to characterize coefficient of friction (CoF) and wear rates of metals under different wear modes. The experimental procedure used a micro-abrasion tester to apply loads to metal samples in contact with a rotating steel ball under various conditions to produce different wear modes. Results found that pure rolling abrasion generated the highest wear rates while dry sliding abrasion produced the lowest wear rates and CoFs. The research concluded the tester was useful for evaluating CoF under different tribological pairs and conditions.
Surface condition impacts part performancweDave Davidson
1) Surface finish and the presence of burrs on aircraft and aircraft engine parts can significantly impact part performance and lifespan by increasing stresses, corrosion, and reducing sealing abilities.
2) Specialized finishing processes are used to remove burrs, round edges, and optimize surface texture in ways that reduce stresses, improve fatigue life, enhance corrosion resistance, and improve sealing of joints.
3) Paying close attention to edge and surface quality is important in aerospace applications due to the potential for catastrophic failure if surfaces are improperly finished or contain defects.
This document summarizes Mitchell Smith's undergraduate research project on friction stir welding of similar and dissimilar metal alloys. Smith conducted trial welds of aluminum alloys to understand the friction stir welding process and machine settings. Welds were made of similar aluminum alloys and dissimilar aluminum-copper alloys. Challenges included preventing separation of metal pieces during welding. Further tests are needed to characterize the welds and properties of the welded metals, including microstructural analysis, tensile tests, and impact tests. Continued research on welding nano-reinforced metals could expand applications of friction stir welding in fields like nuclear engineering.
Friction Stir Welding of Magnesium Alloys - A Reviewmsejjournal
The selection of proper material for each application is a critical part in every manufacturing industry.
In the field of aerospace and automobile the major requirement is light weight yet strong material which
can possess every aspect of design parameters. Magnesium alloy one of the major raw material used in
these industries due to its light weight, good thermal conductivity etc. Also Friction stir welding is the
joining process that is being used in these industries as it is a solid state joining process. This paper
gives a detailed review about Friction Stir welding of Mg alloys. The review period is considered from
2009 to 2015.A detailed review about Friction stir welding of Mg alloys has not been done before in this
manner. This review work may be a ready reference for subsequent researchers.
Effects and defects of the polypropylene plate for different parameters in fr...eSAT Publishing House
1. The document analyzes the effects of different parameters on friction stir welding of polypropylene plates, including tool pin profile, rotational speed, and welding speed.
2. Microstructural images and hardness tests were used to evaluate the quality of the welds under different conditions.
3. The results showed that a threaded pin profile with rotational speed of 2250 rpm and welding speed of 40-50 mm/min produced welds with the fewest defects in the polypropylene material.
Effect of tool offset and tilt angle on weld strength of butt joint friction ...Alexander Decker
This document discusses an experiment investigating the effect of tool offset and tilt angle on the weld strength of friction stir welded butt joints between AA2024 aluminum alloy and copper. Specimens were welded using a tool with 2 degree tilt and various pin offsets. Tensile testing showed specimens welded with 1 mm pin offset and 2 degree tilt had the highest strength. Microstructure analysis revealed intercalated aluminum and copper pieces in the weld nugget, as well as copper hooks providing strength. Welding with tilt improved strength by removing voids compared to zero tilt.
Influence of design parameters in weld joint performanceIAEME Publication
1) A flange connection in an oil and gas pipeline failed prematurely due to cracking. Investigation found the failure was likely caused by recently grinding the nipple wall thinner to fit the flange, which reduced strength and increased stresses.
2) Welding also caused a brittle microstructure making the material vulnerable to cracking. Sulfur levels near the crack were twice as high as the bulk material further away, indicating sulfur embrittlement contributed to failure.
3) Design factors like reducing wall thickness and welding accelerated failure by increasing stresses and embrittling the material through higher sulfur levels and microstructure changes.
This document summarizes friction stir welding (FSW), including its working principle, microstructure analysis, tool design, process parameters, advantages, challenges, and applications. FSW is a solid state welding technique that uses a rotating tool to generate frictional heat and mechanically deform aluminum alloys below their melting point. It produces high quality welds with improved mechanical properties compared to fusion welding. Main applications are in shipbuilding, aerospace, and automotive industries.
Modeling and Simulation of Base Plate of Friction Stir Welding-Advanced Weldi...ijsrd.com
Friction stir processing is an emerging technique based on the principles of friction stir welding (FSW). It is a solid-state joining method that is energy efficient, environmentally friendly, and versatile. It is considered by many to be the most significant development in metal joining in a decade. The basic concept of friction stir processing is remarkably simple. A rotating tool with pin and shoulder is inserted in the material to be joined, and traversed along the line of interest. The heating is localized, and is generated by friction between the tool and the work piece, with additional adiabatic heating from metal deformation. A processed zone is produced by movement of material from the front of the pin to the back of the pin.
The document reviews friction stir welding (FSW), a solid-state welding technique. It discusses FSW's advantages over fusion welding in avoiding issues like porosity and cracking. The document then summarizes several studies on FSW of titanium and other alloys, examining effects of parameters like rotational speed on microstructure and properties of the welds. It investigates FSW of titanium to steel and aluminum to titanium, describing interfacial structures formed under different welding conditions.
This document discusses selecting materials for punching and forming tools. It describes the different stresses that tools experience during operations like cutting, cold forming, deep drawing, bending, and rolling. It emphasizes the importance of choosing a material suitable for the intended purpose that balances properties like hardness, wear resistance, compression strength, and toughness. Cold-work tool steels are commonly used and can be non-alloyed or alloyed with carbide-forming elements like chromium, molybdenum, and vanadium to improve properties. High-speed tool steels are also used due to their high wear resistance and hardness at high temperatures.
The document summarizes an experimental analysis of weld strength in friction stir welding of different grades of aluminum alloy using different tool geometries. Specifically, it analyzes welding 6061, 7005, and 8011 aluminum alloys with a cylindrical tool and tapered threaded tool. Tensile testing found that the tapered threaded tool produced stronger welds across all aluminum grades compared to the cylindrical tool, with strengths increasing up to 30%. This is because the threaded tool generates more friction and distributes the metal more evenly in the weld zone. Visual analysis also found the threaded tool produced better surface finish quality than the cylindrical tool.
FRICTION STIR WELDING OF ALUMINIUM ALLOYS - A REVIEWIAEME Publication
This welding is a novel process used to join metallic alloys. Friction stir welding is in vogue in aerospace, automotive and other industrial establishments for connecting alloys like aluminum, magnesium and copper. Rotational speed, welding speed and the angle of attack are important in the process of FSW. They analyze the weld quality. FSW produces stronger weld joint then the original material in selected parameters. FSW is a solid-state process, where metal is not melted uses a cylindrical shouldered tool with a profiled pin rotated and gradually plunged into the weld joint between two metal parts of plate or sheet that are to be welded together.
Influence of Elastic Deformations on the Adhesion of the ZRN Coating on the C...ijtsrd
Clinching is a mechanical joining method. Is it utilized in automobile industry as an alternative method to resistance spot welding. Considering that various types of materials are joined in car body production, PVD coatings are used to increase the lifetime of the clinching tools. Hot dip galvanized steel sheets were used for joining by clinching method. The zirconium nitride ZrN PVD coating was deposited on the surfaces of clinching tool. The loss of cohesion properties of coating was observed at punch´s R0.2 radius after 300 clinched joints. FEM analysis was used to show the punch´s critical part when the tool is under load. LuboÅ¡ KaÅ¡c¡k | Renâ Kubk "Influence of Elastic Deformations on the Adhesion of the ZRN Coating on the Clinching Tool" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29856.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/29856/influence-of-elastic-deformations-on-the-adhesion-of-the-zrn-coating-on-the-clinching-tool/lubo%C5%A1-ka%C5%A1c%C3%A1k
Scrum Takımlarının Büyüklüğünün Takım Başarısına EtkisiYasemin CIRT
Bu rapor Yasemin CIRT tarafından "Scrum Takımlarının Büyüklüğünün Takım Başarısına Etkisi" konulu lisans bitirme tezi kapsamında hazırlanmıştır. Rapora dahil edilen veriler İstanbul'da bulunan 40 Scrum takımının Scrum Master'ları tarafından değerlendirilmesi ile elde edilmiştir.
Armenag Dekmezian is a chemist with expertise in polyolefin materials science and technology. He has over 30 years of experience working for ExxonMobil Chemical Company in roles such as section manager, supervisor of a polymer characterization laboratory, and technical research associate. He now works as a forensic expert providing analysis related to polyolefins. Dekmezian has a PhD in Chemistry from UCLA and has authored over 20 publications and holds over 40 patents related to polyolefins.
This document provides a summary of Awangko Arsul Iman Bin Pengiran Sa'adenan's personal and professional details. It includes his contact information, educational background with a Bachelor's degree in Metal Fabrication Technology, career objective to work as a successful and respectable manager, skills in Microsoft Office, AutoCAD, communication, and quality control. It also lists the academic subjects taken in his field of study, extracurricular activities, interests including sports and travel, languages spoken, and references.
Time management is an important generic skill. It involves planning and organizing how to divide your time between different activities. Effective time management requires setting priorities, having a to-do list, and learning to say no to unnecessary tasks.
العدد 150 من مجلة المخطوطات الإخبارية التابعة لمعهد المخطوطات العربية مكتبات اون لاين
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Temporal bone tumors staging and radiological assesmenttamer ebaied
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Este documento proporciona información sobre el estado de coma y su evaluación y diagnóstico. Define el coma como un estado de falta de respuesta psicológica en el que el sujeto permanece con los ojos cerrados. Explica cómo evaluar la profundidad del estado de conciencia, realizar exámenes neurológicos y de laboratorio, e identificar posibles causas orgánicas e intoxicaciones que pueden llevar al coma.
Study of Pitting Corrosion Behavior of FSW weldments of AA6101- T6 Aluminium ...IJERA Editor
Friction Stir Welding (FSW) is a promising solid state joining process widely used generally for Al alloys,
especially in aerospace, marine and automobile applications. In present work, the microstructure and corrosion
behavior of friction stir welded AA6101 T6 Al alloy is studied. The friction stir welding was carried using
vertical milling machine with different tool rotational speeds and welding speeds. The microstructure at weld
nugget or stir zone (SN), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal
were observed using optical microscopy. The corrosion tests of base alloy and welded joints were carried out in
3.5% NaCl solution at temperature of 30º C. Corrosion rate and emf were determined using cyclic polarization
measurement.
Friction stir welding (FSW) was investigated as a potential joining method for aluminum metal matrix composites reinforced with boron carbide (MMC 6061-XX% B4C) due to issues with traditional fusion welding methods. Preliminary results showed that FSW produced superior mechanical properties compared to gas tungsten arc welding (GTAW), with FSW joints exhibiting similar tensile properties to the base material. However, tool wear was found to be severe, preventing long welds. Overall, the study demonstrated that FSW is a viable process for joining MMC 6061-XX% B4C, offering benefits over conventional fusion welding by reducing defects and improving mechanical properties.
This document discusses detecting defects in friction stir welding using continuous wavelet transform (CWT) on force signals. CWT is applied to the vertical force signal to generate a scalogram showing the frequency-time representation as a grayscale image. Peaks in the image indicate locations of defects where abrupt changes occurred in the force signal. Statistical analysis of the CWT coefficients helps precisely localize defects. Experiments were conducted on aluminum alloy welds under varying parameters. CWT showed better defect localization than other transforms and analysis of the CWT coefficients accurately identified locations of defects in the welds.
Research on the influence of sagging and continuous undercut on the capacityIAEME Publication
This document discusses research on the influence of sagging and undercut imperfections on the capacity of butt-welded joints. Standard probes were made from steel S235JR using prescribed welding techniques. Sagging was simulated on one side of a probe, while undercut was simulated on both sides of another probe. The probes underwent visual examination, radiographic testing, tensile testing, bending testing, and toughness testing. Results from these tests were used to analyze the stress distribution and behavior of the imperfect welded joints compared to a standard welded joint without imperfections using finite element analysis software. The purpose of the research was to better understand how such imperfections affect welded joint design to optimize safety and cost.
This document summarizes a study on minimizing surface defects in bars and wire rods that originate from continuous cast billets. It describes a methodology developed to determine the origin of defects, which includes metallographic studies using etchants on samples from rolled products and billets. Common defects like pin holes and transverse cracks are analyzed, showing their appearance in billets and during rolling. Causes of pin holes are identified as internal oxidation from casting powder decomposition, and causes of transverse cracks include tensile stresses during casting or strengthening that lead to cracks, especially in corners. Solutions recommended involve optimizing casting powder distribution and secondary cooling to avoid temperature ranges that cause cracking.
Defects in rolled sheets-A paper reviewIRJET Journal
1. The document discusses defects that can occur during the metal rolling process, including surface defects and internal structural defects.
2. Surface defects are caused by impurities or inclusions on the metal surface, while structural defects include edge cracks, alligator cracks, wavy edges, and more.
3. Many rolling defects result from uneven heating, rolling, quenching, stress during the rolling process, non-uniform material flow, and imperfections in starting materials or rolls. Remedies include trimming edges, cambered rolls, and controlling roll deflection.
This document describes procedures for conducting a deep drawing test to determine the ductility of sheet metal. The test involves clamping a sheet metal sample at its edges and forcing a conical or hemispherical punch into the sample to form a cup shape. The depth the punch can form before fracture occurs is measured to assess the sample's ductility. The test determines whether a material is suitable for deep drawing processes which shape sheet metal through tensile stretching and compressive forces without cracking.
Investigation and analysis of metallurgical and mechanical properties of aa11...Alexander Decker
1. The document investigates the mechanical and metallurgical properties of friction stir welded joints of AA1100 aluminum alloy fabricated at different tool rotational speeds and material positions.
2. Tensile tests, microhardness tests, and optical/SEM microscopy of the welds were used to evaluate the mechanical properties and microstructure of the joints.
3. The results showed that joints welded at 1200 rpm had the optimum properties, with smooth weld surfaces and good tensile strength, yield strength, and elongation. Microhardness was also highest at this welding condition.
The document discusses multi response optimization of friction stir welding (FSW) parameters for aluminum alloy AA6105 using the Taguchi method. It first provides background on welding processes including FSW. It then discusses factors that affect FSW quality like rotational speed, welding speed, and tilt angle. The document proposes using an L9 orthogonal array experiment with three control factors and mechanical properties and microstructure as response variables. The methodology involves conducting experiments, applying Taguchi analysis and ANOVA to optimize parameters for properties like tensile strength and hardness. The research aims to minimize defects and improve joint quality of AA6105. Equipment for FSW and response testing is also detailed.
Various Parameter Effects on Friction Stir Welding- A ReviewIRJET Journal
This document reviews the effects of various parameters on friction stir welding. It summarizes research that has studied how welding parameters like rotational speed, travel speed, tool geometry, and plunge depth impact the quality of friction stir welds. The document also reviews studies on double-sided friction stir welding and how parameters like shoulder diameter and plunge depth influence mechanical properties of the welded joints. Overall, the review examines how process parameters can be optimized in friction stir welding to produce welds without defects and with improved mechanical properties.
This document summarizes a study that investigated the mechanical and metallurgical properties of friction stir welded AA1100 aluminum alloy joints. Different welding parameters were tested, including tool rotation speed (800-1400 rpm) and material positioning (advancing vs. retreating side). Microhardness, tensile, and fracture surface tests were used to evaluate the mechanical properties. Optical and SEM microscopy were used to analyze the microstructural evolution. The goal was to understand how processing parameters affect properties and defect development in similar AA1100 alloy joints.
IRJET- Emphasis of Plate-Thickness and Groove Angle on Distortion for Mild St...IRJET Journal
The document summarizes research into minimizing welding distortion, which is a change in shape that occurs between welded plates before and after welding. The research investigates the effect of plate thickness (6, 7, and 8mm) and groove angle (60, 90, and 120 degrees) on angular distortion in mild steel butt joints welded using manual metal arc welding (MMAW). Mathematical models are developed using response surface methodology to predict transverse and longitudinal shrinkage distortion based on plate thickness and groove angle. Analysis of variance (ANOVA) testing shows that the models accurately predict distortion. The research aims to provide empirical data to better understand different types of welding distortion.
Mechanism of Fracture in Friction Stir Processed Aluminium AlloyDr. Amarjeet Singh
Aluminium alloys are used for important
applications in reducing the weight of the component and
structure particularly associated with transport, marine,
and aerospace fields. Grain refinement by scandium (Sc)
addition can eliminate the casting defects and increase the
resistance to hot tearing for high strength aluminium alloys.
FSP for cast aluminium alloys have been focused and it has
great advantages including solid state microstructural
evolution, altering mechanical properties by optimizing
process parameters. These parameters are tool rotational
speeds (720, and 1000 rpm), traverse speeds (80, and 70
mm/min), and axial compressive force at 15 kN, etc. The
mechanical properties had been evaluated on FSPed
aluminium alloy with different microstructural conditions.
Fracture properties of aluminium alloys are very important
for industrial applications. Tensile and fracture toughness
properties were correlated to microstructural and
fractographic features of the aluminium alloys need to
explore their essential failure mechanisms.
IRJET - Characteristics of Butt Joint Produced by Friction Stir Welding ProcessIRJET Journal
The document discusses characteristics of butt joints produced using friction stir welding (FSW) of aluminum alloys. It investigates the effects of various FSW process parameters on the mechanical properties and microstructure of the welded joints. Specifically, it examines rotational speed, transverse speed, and tool geometry. Joints of aluminum alloy AA5083 were welded and tested in tension, hardness, impact, and corrosion to analyze properties. The results showed that process parameters significantly affected the weld strength and microstructure. Defect-free joints with optimal mechanical properties could be produced using appropriate FSW conditions.
Effects of welding current and arc voltage on fcaw weld bead geometryeSAT Journals
Abstract Flux cored arc welding(FCAW) process is characterized with its high deposition rate and productivity. Control of the operating parameters in FCAW is essential to obtain high production rates and good quality welds. Bead on plate welds were carried out on mild steel plates to study the influence of welding current and arc voltage on weld bead geometry parameters. The weld bead coss-sections were metallographically investigated. The effects of these welding parameters were evaluated by measuring penetration depth, reinforcement height, bead width, wetting angle, electrod deposit area and plate fusion area. The bead cross-section area and the weld shape factor were calculated from the measured results. The effects of welding parameters on weld bead geometry have been presented by histograms. Key Words: Flux cored arc welding, arc welding parameters, weld bead geometry, weld shape factor
a survey on submerged arc welding (saw) reviewNEERAJKUMAR1898
This document provides a review of submerged arc welding (SAW). It begins with an introduction to SAW, describing it as a process where the arc is shielded by a blanket of granular and fusible flux. It then reviews prior literature on SAW, discussing studies on the effects of process parameters on weld geometry and quality, and post-weld heat treatments. The document also outlines the principles of SAW, including the continuously-fed wire electrode and use of flux to shield the arc from atmosphere and increase heat efficiency. It provides diagrams illustrating the SAW process.
In the current work, aluminum AA1050 plates has been successfully joined using friction stir
welding (FSW) technique. The effect of processing parameters such as tool rotation speed and travel speed
on the mechanical properties are investigated. Residual stress has been carried out using the destructive
cutting length method; the results found that common stresses are compressive type, which are formed due to
friction stir welding process. The results revealed that welding travel speed has a remarkable influence on the
resultant residual stress.
Study and Analysis of the Fatigue Behaviour of Friction Stir Butt Welded Dis...IRJET Journal
1) The study analyzed the tensile strength and fatigue behavior of friction stir butt welded dissimilar aluminum alloys AA6082 and AA5754.
2) Fatigue tests showed the dissimilar welds had lower tensile strength and fatigue strength than the base materials AA6082 and AA5754, but comparable strength to AA5754.
3) The fatigue performance of the AA6082 and AA5754 friction stir welded joints showed a shallower stress-life (S-N) curve with improved fatigue performance at lower stress ranges.
FEM Analysis of Stress Predication of Aluminum Wire Rod in Drawing OperationIRJET Journal
This document analyzes aluminum wire drawing operations to understand causes of wire breakage. Finite element analysis is conducted using ANSYS to simulate wire stresses, strains, die stresses, and temperatures at critical drawing stages. The analysis considers different friction conditions to find optimal parameters that minimize defects and breakage. Material properties of the aluminum alloy wire and polycrystalline dies are defined. Simulation results reveal plastic deformation patterns and maximum stresses under various lubrication conditions to suggest preventative measures and reduce breakage during drawing.
FSW PROCESS DISSIMILAR (Al) AT 3G POSITIONMin Dzulkiflee
This document summarizes a research project on friction stir welding (FSW) of dissimilar aluminum alloys. The objectives were to design an FSW weld for joining different aluminum series in a 3G position, evaluate the best welding parameters such as rotational and transverse speed, and analyze tensile strength properties. FSW was performed using different transverse speeds and a fixed rotational speed. Tensile testing showed the highest strength was achieved with a transverse speed of 86mm/min, meeting the project's objectives.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
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Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
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solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
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Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
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The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
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Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
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Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
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Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Comparative analysis between traditional aquaponics and reconstructed aquapon...
S02 p1 - leonard, lockyer
1. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
FLAWS IN FRICTION STIR WELDS
A J Leonard and S A Lockyer
TWI Ltd, Granta Park, Great Abington, Cambridge, CB1 6AL, UK
Abstract
One of the major drivers for using friction stir welding for aluminium fabrication is the low
incidence of weld flaws compared to that produced by conventional arc welding. However,
the process does have its own characteristic flaws. A number of different process variables
affect the quality of a joint produced by friction stir welding: tool design, tool rotation and
travel speeds, tool heel plunge depth and tilt angle, welding gap, thickness mismatch and
plate thickness variation. Successful, reproducible welds may be produced by operating
within process “windows”. However, problems may arise when the welding conditions
deviate from the standard operating window. In such circumstances, flaws may be
generated. In the current work, a number of flaws encountered in friction stir welds, in
particular voids, joint line remnants and root flaws were generated in an Al-Cu-Mn-Si-Mg
alloy by using welding parameters outside of the established tolerance box for producing
flaw-free welds. The welds were characterised using X-ray and ultrasonic non-destructive
testing techniques and by metallographic sectioning. The causes of such features are
described and recommendations are made to prevent their occurrence.
INTRODUCTION
Flaws are inherent in most materials joining processes. For example, a number of flaw types
are associated with fusion welding of aluminium alloys, most notably weld metal porosity
(1), Fig.1, and in certain alloys, weld metal solidification cracking and heat affected liquation
cracking (2), Fig.2. Such problems have contributed to the view that some aluminium alloys,
in particular some of the 2xxx and 7xxx series alloys, are difficult to fusion weld
successfully. Friction stir welding, being a solid state process, has overcome the problems of
porosity and hot cracking encountered in fusion welds. In addition, being a largely automated
process, it is possible to produce defect-free welds reliably when operating within an
established parameter, or “weldability” envelope (3). The precise details of any operating
envelope will depend on the material being welded and the actual quality control criteria
specified. The rapid commercial application of the process is testimony to its robustness
within defined operating parameters; to date, the authors are aware of no major problems that
2001-3-16-8-34-41-003 2001-1-31-9-38-36-003
Fig.1 Porosity in an aluminium arc weld. Fig.2 Hot cracking in an aluminium arc weld.
2. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
have been reported with regard to the occurrence of defects. However, it is inevitable that, as
the process becomes more widely used, and operating conditions are pushed to their limits to
satisfy needs for improved joint properties and productivity, flaws will be introduced.
Two previous studies have reported on flaws in friction stir welds (4,5), in which tool rotation
speed and welding speed were evaluated. The authors identified void formation and a root
flaw. These were attributed to high travel speeds coupled with slow tool rotation speeds.
Inadequate tool plunge depth was attributed to the cause of the root flaw. The objective of
the current paper is to characterise the flaws that may, typically, be introduced into friction
stir welds when operating outside of the “standard” set of optimised welding parameters. This
will assist end users of the technology with an awareness of how process variation may
introduce flaws and to enable appropriate process modifications to be made to eradicate them.
The results reported were all generated on welds made in 6mm thick plate from an Al-Cu-
Mn-Si-Mg alloy 2014A, produced using altered conditions derived from, but outside of, the
original TWI development work. Specifically, flaws were generated by the variation of
welding speed, welding force (forging pressure), tool pin height and surface oxide thickness.
Table 1 Summary of X-ray, ultrasonic and metallographic inspection of each of the welds in
alloy 2014A.
Weld
Welding
speed
mm/min Other details X-ray result
Ultrasonic
inspection result Sectioning results
W9 90 Shortened pin
used
No defects
recorded
No defects recorded Root flaw
W10 90 2mm shim
inserted
between
plates
No defects
recorded
No defects recorded No flaws found
W11 90 Total pressure
limited to
500psi
Two large voids,
65mm and 140mm
long
Two voids: No 1,
5mm deep, 45mm in
length No 2, 4.9 to
5.6mm deep 120mm
in length
Large voids on
advancing side of
the weld
W12 180
-
No defects
recorded
No defects recorded Root flaw + void
beneath surface of
weld
W13 250 - No defects
recorded
No defects recorded No flaws found
W14 300 - No defects
recorded
No defects recorded Small voids
beneath surface of
weld
W15 400 - Large void and
associated small
voids at stop end of
weld: area affected
85mm
Void 4.0m deep
11mm in length
Large void on
advancing side of
weld
W17 90 20µm
anodised
surface on
plates
Feint linear
indications full
weld length
Intermittent
reflector full weld
length, 4.5mm deep
Oxide inclusions
(joint line remnant)
3. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
Characterisation was performed using two non-destructive techniques: X-ray radiography and
ultrasonic inspection, the latter being performed manually utilising a compression wave at
5MHz with a 10mm diameter probe; metallographic sections were also prepared to illustrate
the features found by non-destructive examination. Table 1 summarises each of the welds
produced and the flaws encountered. Three main flaw types are discussed: voids, root flaws
and joint line remnants.
VOIDS
A number of the welds contained voids, which ran along the advancing side between the weld
nugget and the remainder of the thermomechanically affected zone (TMAZ). Limiting the
forging pressure generated a void along the entire length of weld W11, which was
predominantly, although not exclusively, surface-breaking (Fig.3). If welding pressure were
to vary momentarily during welding, voids may be generated that visual appraisal alone may
not detect. A similar void in terms of appearance was generated in a weld produced at a speed
of 400mm/min, over a factor of four times faster than a conventional friction stir weld in
alloy 2014A using established technology. In this particular case, void formation was, in part,
caused by the plates moving apart and the tool lifting (Fig.4).
Advancing side
2000-7-25-11-12-59-002a
Fig.3 A void on the advancing side of a weld (W11, mm scale).
67363_01
Fig.4a A surface-breaking void in a weld produced at 400mm/min (W15).
4. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
Advancing side
2000-7-25-11-45-33-002a
Fig.4b A surface-breaking void in a weld produced at 400mm/min (W15, mm
scale).
The location and shape of the voids provide useful information concerning the development
of the characteristic microstructure observed in aluminium alloy friction stir welds. In each
case, the voids were on the advancing side of the weld and showed a clear delineation
between the region of the nugget and the remainder of the TMAZ. The fine-grained nugget
exhibited clear scallops (Fig.5) which indicated that this region was formed by stirring and
forging material either side of the joint line. The almost vertical edge of the advancing side
of the void which was not at the original joint interface, indicates that material had been
swept away by the rotation of the tool, the final joint being then formed by forging the nugget
material into the created void. The tool shoulder plays an important part in forging the
material that has been plasticised by the rotating pin in the joint line. If insufficient forging
pressure is applied to the tool, the workpiece may ride up and prevent complete
consolidation. When welding at higher travel speeds, the material receives less work per unit
of weld length, i.e. fewer tool rotations per mm. Under such conditions, the plasticised
material may be cooler, and less easily forged by the shoulder, resulting in voids remaining
unconsolidated.
2000-8-4-14-16-16-003a
Fig.5 A void on the advancing side of weld W11.
Bendzsak et al (6) and Colegrove (7) have developed mathematical models for material flow
during friction stir welding. Both models predict a region of transition between a region of
5. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
rotational motion of material immediately beneath the tool shoulder and a region in which
material is extruded past the rotating tool pin. Bendzsak et al (6) described the motion of the
transition region as chaotic. Both models predict flow singularities in this region on the
advancing side of the weld. Bendzsak et al attributed these to be the source of weld defects
(voids). The current work supports the theoretical models in that voids were generated at the
locations in which they were predicted to occur.
Small voids were also observed elsewhere in the welds. In some instances, they were due to
inadequate forging. Others were present intermittently, below the top of the weld when the
welding speed was increased (Fig.6). The features corresponded to the region in which the
tool shoulder left a mark on the top surface, in the form of a series of advancing semi-circles.
It may be noted that all of the voids in the current work, with the exception of the small voids
below the weld surface, were detected by conventional X-ray radiography and ultrasonic
inspection. The small voids below the top of the weld may be removed by light machining of
the weld surface.
2000-3-30-10-31-16-003a
Fig.6 A void beneath the upper surface of a weld produced at 180mm/min (W12).
Christner and Sylva (8) investigated the effect of the presence of a joint gap on the
mechanical properties of friction stir welds in 6.4mm thick alloy 2014A-T6. As in the
current work, joint gaps were achieved by the insertion of shims at each end of the weld panel
assembly. The length of weld produced and the distance between the shims was not
presented, but it was recorded that a joint gap of 2.3mm, which represented 36% of the plate
thickness, could be tolerated without a significant reduction in joint strength. A joint gap of
3.2mm, or 50% of the thickness, resulted in incomplete joint consolidation and the presence
of a cavity along the advancing side of the weld. In the current work, a joint gap of 2mm
(33% of the plate thickness) was tolerated, over a span of ~260mm, without the presence of
any discernible flaws. This is consistent with the findings of Christner and Sylva, although in
the current work the actual joint properties were not measured.
ROOT FLAWS AND JOINT LINE REMNANTS
Two principal examples of joint line remnants were generated in the current work. Firstly, by
use of a shortened pin, a root flaw was created. During the formation of the friction stir weld,
it is vital that the oxide interface between the two butting plates is adequately disrupted in
order to form a bond. The correct depth of penetration of the tool pin is essential to ensure
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International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
that this occurs. Where a shortened pin is used, where the tool plunge depth is incorrectly set,
or where there is poor alignment of the tool relative to the joint line, a root flaw is produced;
the original plate interface is only partially disrupted and can still be identified on a cross-
section, Fig.7b. In one weld, which essentially had the correct pin height and plunge depth, a
root flaw was still produced. In this instance, either the plunge depth cannot have been
adequate, or the joint line was badly misaligned relative to the tool axis of rotation,
generating the flaw.
Advancing side
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Fig.7a A root flaw in weld W9 (arrowed, mm scale).
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Fig.7b Higher magnification photomicrograph of weld W9, showing the root flaw (arrowed).
Such root flaws do not necessarily represent an absence of any bond, indeed some regions of
weak bonding may be present. However, work to date at TWI (9) on welds in alloy 5083-
H321, which contained similar features, did show a reduction in tensile properties and a loss
in fatigue strength. Therefore, such features should not be regarded as innocuous. Currently,
NDT techniques such as radiography and dye penetrant inspection, as well as visual
examination, are not reliable for detecting root flaws, and, indeed, the root flaws were not
detected in the current work. The only definitive method that is currently available is a
destructive bend test with the root in tension (10), although efforts are being applied to the
7. 4th
International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
development of NDT techniques that are capable of detecting them. In the case of critical
applications, machining the weld root may be an effective measure to remove such features.
A second type of joint line remnant is the distribution of oxide particles through the thickness
of the weld, Fig.8. In the current work, the oxide coating, which normally covers the surface
of aluminium, was deliberately thickened by anodising. In this instance, a visible dispersed
oxide line was produced in the weld, which was also of sufficient size to be detected by both
radiography and ultrasonic inspection. Previous work at TWI (9) produced joint line remnant
flaws in welds in alloys 5083-O and 6082-T6. In the former alloy, the feature was introduced
by increasing the welding speed, resulting in less disruption of the oxide per mm advance of
the tool; in the case of the latter, an oversize tool shoulder was employed, resulting in more
surface oxide being swept into the weld. In each of these welds the tensile properties were
not affected by the features, with the exception of a small drop in ductility in the 5083 weld.
The fatigue strength did not appear to be affected by the presence of the flaws in the welds
examined and fracture mechanics calculations were conservative in comparison with the test
results. The TWI work concluded that such a flaw resulting in a loss in mechanical
properties should be viewed as a crack and therefore not tolerable. Even if there is no loss in
mechanical properties, the feature is clearly undesirable and is best minimised by careful
machining of the butting faces to reduce the quantity of oxide prior to welding and control of
welding speed. Improvements in tool design may also be of benefit in disrupting oxidised
layers.
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Fig.8a
Advancing side
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Fig.8b Joint line remnant in weld W17 (mm scale).
PRACTICAL IMPLICATIONS
Table 2 summarises the main flaw types in friction stir welds identified in this work and other
published information. It also includes details of the factors causing their formation. It
should be noted in the case of voids produced in the current work that only some of the
welding parameters were varied, namely welding pressure, travel speed and joint fit-up; other
parameters, such as tool design and rotation speed, may also influence flaw formation.
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International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
Comprehensive mathematical modelling of the welding process, as adopted by Bendzsak et al
(6) and Colegrove (7), may result in a greater understanding of how individual welding
parameters interact, permitting weld procedures to be developed without recourse to a large
matrix of test welds in order to establish a tolerance window. The Table provides an initial
resource for the identification of problems encountered in production welds, and an aid to
their eradication.
Table 2 Flaws that may be present in friction stir welds and their causes.
Flaw Type Location Causes
Void Advancing side at edge of weld
nugget.
1. Reduced forging pressure.
2. Welding speed too high.
3. Plates not clamped close
enough together. Joint gap
too wide.
Void Beneath top surface of weld Welding speed too high
Joint Line Remnant Weld nugget, extending from the
root of the weld at the point
where the original plates butted
together.
1. Inadequate removal of oxide
from plate edges.
2. Inadequate disruption and
dispersal of oxide by tool.
3. Increase in welding speed.
4. Increase in tool shoulder
diameter.
Root flaw Weld nugget, extending from the
root of the weld at the point
where the original plates butted
together.
1. Tool pin too short.
2. Incorrect tool plunge depth.
3. Poor joint to tool alignment.
Currently, no national or international inspection criteria exist for evaluating the quality of
friction stir welds. Although, an AWS standard is in preparation (10). Lloyds Register of
Shipping has issued guidance notes for weld qualification (11), which have been based
largely on the requirements for arc welds in British Standard BS EN288 part 4 (12). This
latter document specifies 100% visual examination, 100% radiographic or ultrasonic
inspection and 100% penetrant inspection, together with bend tests, tensile tests and
metallography. Lloyds have specified penetrant inspection on only the weld root for friction
stir welds. The acceptance levels for weld imperfections in BS EN288 Part 4 are described as
level B – stringent, as defined in BS EN30042 (13). In the current work, flaws were identified
by a combination of non-destructive and metallographic inspection techniques. No attempt
was made to determine the limits of detectability of flaws by these techniques. However, if
weld qualification standards are to be developed for friction stir welds, further work will be
necessary in determining these limits.
CONCLUSIONS
1. Voids may be formed when insufficient forging pressure is applied to the weld. Welding
too fast may also result in similar effects.
2. A joint gap of up to 2mm may be tolerated when welding 6mm thick 2014A plate without
the formation of weld flaws.
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International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
3. Joint line remnants in the form of inadequately dispersed oxide may be produced if
inadequate pre-weld cleaning is performed or the welding speed is too high. Evidence
suggests that joint line remnants may be tolerated in certain circumstances, but are best
avoided. Machining the plates prior to welding and control of welding speed are effective
in restricting their appearance.
4. Joint line remnants in the form of root flaws are introduced when either insufficient pin
depth or tool plunge depth is selected for the joint, or when there is poor tool to joint
alignment. These flaws have been found to be damaging to both tensile and fatigue
properties. Appropriate selection of the above parameters may eliminate these flaws.
However, for critical applications, machining of the weld root may be advisable.
5. Cross weld tensile testing and root bend tests are recommended to identify damaging joint
line remnants and root flaws.
ACKNOWLEDGEMENTS
This work was funded by Industrial Members of TWI as part of the Core Research
Programme. The authors are grateful for the assistance of colleagues at TWI who assisted
with the work.
REFERENCES
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International Symposium on Friction Stir Welding, Park City, Utah, USA, 14-16 May 2003
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