FSW and Violence

The basic principle of Friction stir welding (FSW) is heating the metal to a temperature below the re-crystallization temperature thus reducing the welding crack such as porosity band hot crack with are commonly formed in the conventional welding method due to alloy's low crystallization temperature and high heat dissipation nature. The quality of friction welding is good when compared to other fusion welding technique. The main influence parameter in FSW is rotational speed welding traversing speed and pressure applied against the joint. AA6061 and AA8011 aluminium alloy has high strength to weight ratio. They have main application in the field of marine, aerospace and automobiles. As it is difficult to perform number of experiments to find out the level combinations which yield good mechanical properties like tensile strength, impact strength and hardness number, Taguchi L9 orthogonal array is used to reduce the number of experiment. The material is bought and are cut into specific material and polished. They are then welded based on the different experiment obtained from Taguchi method. After welding is done the metals are cut as per the specific standard. The results are then analyzed by using ANOVA statistical tools. ANOVA table clearly shows the percentage of contribution of each factors can be determined. The best welding quality is found out by comparing the result obtained from tensile testing, impact testing and by micro-hardness testing. Scanning Electron Microscope (SEM) technique was used to examine the quality of surface texture.

The metal joining processes have been evolved a lot. Various techniques have been introduced to observe and evaluate the in-depth study of various welding techniques. Friction stir welding process is one of the well accepted solid state joining process. This research paper represents attempts and experiments made to do 13 mm thick plate friction stir weld with the help of simple vertical milling machine. The experimental procedure followed was bi directional multi pass FSW. The distortion of plate is common phenomena in welding but evolution of distortion while conducting solid state welding process is also interesting observation. The distorted plate leads to failure of component considering loading cycles which are concerned with the weld plate. The distortion studies have been conducted using Vernier height gauge and plate clamping consideration with reference plate and slip gauge.

Copper and its alloys possess a wide range of properties these make them valuable for many applications. There are several properties like as Good conductivity of electricity and heat is combined with strength, ductility and excellent corrosion resistance etc. Copper has made possible the continued, efficient development of the electrical industry because it has the highest conductivity of the commercial metals and it has good mechanical properties at low, ambient and elevated temperatures, is easily fabricated or cast to shape and can be joinned. The present paper analyzes the weld joint of pure copper which is made by using friction stir welding (FSW) process. The mechanism of thermo-mechanical processes of the FSW method has been studied and established a correlation between the weld zone and its microstructure. The various Parameters of the FSW welding processes influencing the zone of the base material and the mechanical properties of the resulting joint are analyzed.

The objective of this work is to develop a method for detecting the creation of discontinuities (i.e., voids, volume defects) during friction stir welding. Friction stir welding is inherently cost effective, however, the need for significant weld inspection can make the process cost prohibitive. A new approach to weld inspection is required in which an in-situ characterization of weld quality can be obtained, reducing the need for post-process inspection. To this end, friction stir welds with subsurface voids and without voids were created. The subsurface voids were generated by reducing the friction stir tool rotation frequency and increasing the tool traverse speed to create "colder" welds. Process forces were measured during welding, and the void sizes were measured post-process by computerized tomography (i.e., 3D X-ray imaging). Two parameters, based on frequency domain content and timedomain average of the force signals, were found to be correlated with void size. Criteria for subsurface void detection and size prediction were developed and shown to be in good agreement with experimental observations. With the proper choice of data acquisition system and frequency analyzer the occurrence of subsurface voids can be detected in real time.

When compared to conventional welding techniques reported in the literature, the friction stir welding process is an advanced welding technique that offers numerous advantages. In a brief, the advantages: 1. Good weld quality 2. Power consumption is decreased 3. No flux or filler material, etc. This FSW process i s considered as the research project because of its advantages and the growing popularity of the FSW process in various automobile and aerospace industries. The effects of process parameters such as tool rotational speed, weld speed, and tilt angle on the responses and tensile strength in dissimilar welding of Aluminum alloys of various grades utilizing the solid-state welding technique Friction Stir Welding are reported in this work. The weld joint was tested for ultimate tensile strength (UTS) and Brinell harness number (BHN). Taguchi method was used to obtain the optimum process parameters and then ANOVA test was carried out to find the contribution and most significant process parameter effecting the ultimate tensile strength and Brinell hardness number.

AA6061 aluminum alloy has a gathered wide acceptance in the fabrication of light weight structures requiring high strength to weight ratio and good corrosion resistance. Friction stir welding (FSW) is an emerging solid state joining process in which the material that is being weld does not melt and recast. This process uses a non consumable tool to generate frictional heat in the abutting surfaces. The present investigation is aimed to study the tensile strength, microstructures and corrosion behavior of underwater friction stir welding (UFSW) welded joints of AA6061 at variable temperature of water and compare that result with normal friction stir welding process with same parameter. 4 mm thickness has been used as the base material for preparing single pass butt welded joints.

Friction Stir Welding (FSW) is a solid state joining process primarily meant for joining metals and its alloys is also used in the joining of polymers. Researchers have carried out FSW on different thermoplastics. However, the joining of Polyether ether ketone (PEEK), a thermoplastic material with high strength and high temperature resistance used in aerospace, automotive, chemical processing industries and medical applications has not been carried out extensively using FSW. PEEK is a semi-crystalline polymer having a glass transition temperature of 143 C, melting point of 343 C and tensile strength around 100 MPa. This research paper is aimed at joining of PEEK plates by FSW process with different tool rotating speeds (500, 710, 1000 rpm) and welding feed rates (16, 20, 31.5 mm/min) as input process parameters. FSW process is carried out by modifying the milling machine with a specially made suitable fixture for holding the two work materials to be welded. PEEK material (100% virgin) of 5.5 mm thickness is used as the workpiece for the joining process. Experiments are conducted using a mild steel cylindrical tool of 20 mm tool shoulder diameter, 6 mm probe pin diameter and 5 mm probe pin length. The FSW butt joints of PEEK plates are fabricated, characterized and analysed. The study on tensile strength reveals that the strength decreases with increase in tool rotating speed and welding feed rate. The ANOVA results predict that both the tool rotating speeds and welding feed rates are significant parameters. Also hardness is higher on the advancing side of the joint than the retreating side of the joint. The SEM macrograph shows the different zones of FSW processed joints and the mechanism of FSW welded joint is investigated detailed in this paper.

The present investigation for optimization of MIG welding of EN-31 is conducted to establish the influence of MIG welding process parameters on hardness and surface roughness. From the experimental results it is concluded that welding speed is the main influencing parameter for hardness while welding current is least influencing for it. For the case of surface roughness, welding current has major dominance while other parameters were less effective.

Thermoplastic materials are now easily joined by friction stir welding. Joining of thermoplastics in friction stir welding which is based on frictional heat generated through contact between a rotating tool and the work piece. The determination of welding parameters plays an important role in weld strength. In friction stir welding of thermoplastics, traditional tools form a slit on the backside of welded specimen which leads to root defect causes poor tensile strength. Due to the high transparency of this polymer, it was to possible to analyse easily the morphological changes induced by the welding process on it.In this investigation the welding parameters studied were the tool rotation speed which varied between 800 and 1200 (rpm), transverse speed which varied between 40 and 200 (mm/min), axial force ranging from 1 to 5 (KN).An attempt was made to join the polypropylene plate of 5 mm thickness with different tool profiles (square, cylindrical and triangular threaded pin profile). The quality of the joint was evaluated by means of tensile strength and micro structural analysis.

The basic principle of Friction stir welding (FSW) is heating the metal to a temperature below the re-crystallization temperature thus reducing the welding crack such as porosity band hot crack with are commonly formed in the conventional welding method due to alloy's low crystallization temperature and high heat dissipation nature. The quality of friction welding is good when compared to other fusion welding technique. The main influence parameter in FSW is rotational speed welding traversing speed and pressure applied against the joint. AA6061 and AA8011 aluminium alloy has high strength to weight ratio. They have main application in the field of marine, aerospace and automobiles. As it is difficult to perform number of experiments to find out the level combinations which yield good mechanical properties like tensile strength, impact strength and hardness number, Taguchi L9 orthogonal array is used to reduce the number of experiment. The material is bought and are cut into specific material and polished. They are then welded based on the different experiment obtained from Taguchi method. After welding is done the metals are cut as per the specific standard. The results are then analyzed by using ANOVA statistical tools. ANOVA table clearly shows the percentage of contribution of each factors can be determined. The best welding quality is found out by comparing the result obtained from tensile testing, impact testing and by micro-hardness testing. Scanning Electron Microscope (SEM) technique was used to examine the quality of surface texture.

Gender-based violence in the workplace impacts the physical and emotional wellbeing of sex workers and may lead to other health problems, such as PTSD and depression, drug abuse, and a greater likelihood of sexually transmitted infections. This study examines the social context of workplace violence and risk avoidance in the context of legal regulations meant to reduce harms associated with the industry. Ethnographic research, including 18 months of extended field observations and interviews with 190 female sex workers, is used to illustrate how sex workers in Tijuana, Mexico, experience and manage workplace violence. Multiple subthemes emerge from this analysis, including deciding where to work, working with a third party, avoiding theft, and dealing with police. These findings support the idea that the risk of violence is part of a larger "hierarchy of risk" that can result in a "tradeoff" of harms.

The use of polymeric materials has grown widely in various sectors such as packaging, building, electronic, automotive, and aerospace industries. Particularly, Ultra-High Molecular Weight Polyethylene has wide engineering applications and is used in large quantities in automotive oil pans, gears, slides, cams, bearings, fluid reservoirs, and the sports industry. Friction Stir Welding (FSW) is a solid-state process in joining thermoplastic materials. In this investigation, FSW process must be applied to join a UHMWPE plate of 8 mm thickness with specially designed hexagonal tool pin profile. The aim of this study is to examine the effect of main friction stir welding (FSW) parameters on the quality of UHMWPE plate welds. FSW machine, using a tool with a stationary shoulder and no external heating system. The welding parameters studied were the tool rotational speed which varied between 1300 and 1500 (rpm); the traverse speed which varied between 15 and 25 (mm/min), and the axial force ranging from 8 to 10 (KN). Good quality welds are achieved without using external heating, when the tool rotational speed and axial force are above a certain threshold. For high rotational speed and axial force welds have poor material mixing at the retreating side and mild voids at the nugget, tensile strength also obtained very poor. The hardness angle distortion and bead geometry also evaluated. Taguchi design optimum parameters and ANNOVA were found.

To enhance the nature of welding in Aluminium (Al) plate mechanized welding via TIG framework had been created, in which welding pace can be controlled all through welding procedure. Welding of Al plate had been performed out in the single stage. In this stage of welding, one side weld performed over Aluminium (Al) plate by changing distinctive parameters of welding. Rate of welding effect and welding current on the tensile strength of the joint of weld had been analyzed for butt sort of joint in the weld. Micro-hardness estimation of the welded zone had been estimated at the area of the cross-section to comprehend the variation in mechanical property of the zone that is welded. Uniform welding of Aluminium plate is conceivable by the use of the system of automated welding. Quality of welding or strength based on tensile for the joint of weld relies upon the parameters of welding like current and speed of welding. The welded joint tensile strength improves with rising in current. The hardness value of the zone of weld changes with the distance from the center of weld because of variation of microstructure. At a lower speed of welding, since more power of current available the strength of weld increases.

This paper presents an experimental methodology to determine a Friction Stir Welding (FSW) means of production based on the experimental study of the tool / material mechanical interactions generated during the welding operation. These two stages have been identified as being characteristic for the qualification of a FSW equipment. This paper presents the experimental results of the parametric study done on the plunging and welding phases. Ranges of forces and torques diagrams were established according to the processing parameters, in order to qualify a means of production and to select the processing parameters allowing the operation on the available FSW equipment.

Friction Stir Welding (FSW) is a solid-state welding method which was developed by The Welding Institute and patented in 1999. The process is solid state and relies on local forging of weld region to perform weld. New welding schedules are being continuously developed for materials that are traditionally difficult to join by fusion welding methods (e.g., TIG/MIG). These experiments are performed to find out the best possible parameters to smoothly weld the aluminium 7075 alloys. By using Taguchi robust design of experiment, we selected 3 parameters namely rotation speed and transverse speed and tool shoulder diameter against the optimization function of ultimate tensile strength. The tilt angle and the plunge depth are kept constant. The variation of tensile strength is mainly due to the change in tool shoulder diameter then with welding speed and then with rotation speed. The heat generated is modelled on ANSYS software by inserting the rotation speed, coefficient of friction , material properties , radius of pin etc. The model is validated by conducting the experiment through thermocouples. The model predicted a temperature of about 410 degrees Celsius and the experimental value is 380 degrees Celsius, showing that the welding temperature is about 80% of heat generation. The Taguchi experiment consist of 4 experiments with a range of rotation speeds of 900 and 1120 respectively and a welding speed of 64mm/min and 100 mm/min respectively. The tool shoulder diameter is kept 14mm and 17mm. the welds are cut in transverse direction in order to obtain the UTS test coupon. The best possible combination is found using Taguchi Analysis. This thesis is a collection of data and response variables that correctly informs at what conditions we should weld 7075 alloy. Appropriate SN ratio is calculated and high is the best is considered as our objective function is tensile strength. Some additional tests are also performed namely hardness and microstructure and heat generation in order to identify the behaviors of aluminium alloy. Hardness and heat generated are dependent on the tool shoulder diameter then on the welding speed. This conclusion is derived from Taguchi analysis. This study is useful for the selection of parameters for the further welding operations. However, a change in plunge depth can also be taken into consideration for future scope. As tunneling defect was observed in some runs thus plunge depth has to be varied. Also, the number of experiments can be increased in order to get more refined parameters. Also, the making of base material can also be taken into consideration because of the zinc precipitate distribution. Casted AA7075 has different properties, rolled AA 7075 can have different. I.

Gender-based violence in the workplace impacts the physical and emotional wellbeing of sex workers and may lead to other health problems, such as PTSD and depression, drug abuse, and a greater likelihood of sexually transmitted infections. This study examines the social context of workplace violence and risk avoidance in the context of legal regulations meant to reduce harms associated with the industry. Ethnographic research, including 18 months of extended field observations and interviews with 190 female sex workers, is used to illustrate how sex workers in Tijuana, Mexico, experience and manage workplace violence. Multiple subthemes emerge from this analysis, including deciding where to work, working with a third party, avoiding theft, and dealing with police. These findings support the idea that the risk of violence is part of a larger "hierarchy of risk" that can result in a "tradeoff" of harms.

The use of polymeric materials has grown widely in various sectors such as packaging, building, electronic, automotive, and aerospace industries. Particularly, Ultra-High Molecular Weight Polyethylene has wide engineering applications and is used in large quantities in automotive oil pans, gears, slides, cams, bearings, fluid reservoirs, and the sports industry. Friction Stir Welding (FSW) is a solid-state process in joining thermoplastic materials. In this investigation, FSW process must be applied to join a UHMWPE plate of 10 mm thickness with specially designed triangular tool pin profile. The aim of this study is to examine the effect of main friction stir welding (FSW) parameters on the quality of UHMWPE plate welds. FSW machine, using a tool with a stationary shoulder and no external heating system. The welding parameters studied were the tool rotational speed which varied between 1300 and 1500 (rpm); the traverse speed which varied between 15 and 25 (mm/min), and the axial force ranging from 8 to 10 (KN). Good quality welds are achieved without using external heating, when the tool rotational speed and axial force are above a certain threshold. For high rotational speed and axial force welds have poor material mixing at the retreating side and mild voids at the nugget, tensile strength also obtained very poor. The hardness angle distortion and bead geometry also evaluated. Taguchi design optimum parameters and ANNOVA were found.

In this study, the method of determining the influence of laser welding parameters on the quality provisions of welded joints made with multicomponent heat-resistant alloys was developed. The regularities of the formation of the welded joint structure of multicomponent heat-resistant alloys obtained by laser welding have been studied. The causes and methodological approaches to eliminate defects in the form of hot cracks were identified.

Underwater welding is the process of connecting materials underwater in the presence of water. It is used to maintain and improve the structure in marine and offshore applications. It's utilized for underwater pipeline maintenance, submerged offshore oil drilling, and ship repairs. It can also be found in nuclear power plants and deep-sea mining. Underwater welding is divided into two categories dry welding and wet welding. Dry welding entails enclosing the weld zone in a hyperbaric tank filled with a gas mixture and welding at the prevailing pressure. Wet welding is a type of welding that uses waterproof electrodes and is done directly on the component to be welded. The major benefit of this welding is its simplicity and cost effectiveness, but we can't obtain high weld quality as easily as we can with dry welding. Dry welding, on the other hand, may provide high weld quality, but it is a time-consuming procedure that needs the welder to secure the region with the hyperbaric vessel, and it is also a costly method. Underwater welding has a number of issues, including bubble arc generation, cold cracking, microstructural deformation, and more. We attempted to bring together the most recent developments in the field of underwater welding. We've outlined several techniques that were used to improve welding characteristics as well as important issues that must be addressed. This review article may be used to figure out what measures need to be taken to enhance the underwater weld joint quality.

In this research, the friction stir welding of dissimilar commercial pure aluminium and brass (CuZn30) plates was investigated and the process parameters were optimized using T aguchi L9 orthogonal array. T he considered process parameters were the rotational speed, traverse speed and pin offset. The optimum setting was determined with reference to ultimate tensile strength of the joint. The predicted optimum value of ultimate tensile strength was confirmed by experimental run using optimum parameters. Analysis of variance revealed that traverse speed is the most significant factor in controlling the joint tensile strength and pin offset also plays a significant role. In this investigation, the optimum tensile strength is 50% of aluminium base metal. Metallographic examination revealed that intermetallic compounds were formed in the interface of the optimum joint where the tensile failure was observed to take place.

In this research, the friction stir welding of dissimilar commercial pure aluminium and brass (CuZn30) plates was investigated and the process parameters were optimized using T aguchi L9 orthogonal array. T he considered process parameters were the rotational speed, traverse speed and pin offset. The optimum setting was determined with reference to ultimate tensile strength of the joint. The predicted optimum value of ultimate tensile strength was confirmed by experimental run using optimum parameters. Analysis of variance revealed that traverse speed is the most significant factor in controlling the joint tensile strength and pin offset also plays a significant role. In this investigation, the optimum tensile strength is 50% of aluminium base metal. Metallographic examination revealed that intermetallic compounds were formed in the interface of the optimum joint where the tensile failure was observed to take place.

This paper investigates the influence of the pin geometry on mechanical properties of Aluminium 2024-T351 welded by friction stir welding (FSW). Square, triangle, and cylindrical pin geometries were studied for optimization due to the improvement ratio in tensile and bending strength. The results show that improvement ratio about 10% in mechanical properties was detected at the square pin case compared with the triangle and cylindrical pin geometries. The weld strength increases significantly by decreasing the feeding rate at all travel speeds. Calculations of the scanned zone by stirrer showed that the square pin produced the more significant mixing ratio compared to triangle pin. Development in mixing rate is about 15% by the square stirrer. Also, on the other hand, the results of the calculations of the scanned zone by stirrer pointing to that the size of mixing rate produced by the cylindrical pin is lower than the other types of tool.

The present paper tells about how to predict and optimize the Metal Inert Gas (MIG) welding of AISI 304 Stainless Steel (AISI 304 SS) work pieces, which are most widely in used in many industrial applications. The powerful tool known as Design of Experiments (DOE) was used to optimize the welding process parameters for effective welding joint of the work pieces. The following welding voltage, welding current and welding speed were considered as input parameters and similarly tensile strength, percentage of elongation, and hardness were considered as performance characteristics for DOE application. The values after experimental measurements, compared with corresponding predicted results of tensile strength, percentage of elongation, and hardness. Moreover, the Taguchi Method was also used for DOE and considered L 27 orthogonal array matrix and Signal-to-Noise Ratio, the tensile strength, percentage of elongation, and hardness of the predicted values have been creditably acquired via Fuzzy representation.

Since its inception, friction stir welding, FSW has been promising easy operation and environmental stewardship through contact friction between the tool and the weld part. The Aluminum alloy 2024-T351 was used in both working pieces. Six processes in FSW may include sticking, plunging into the welding pieces, half and full sliding, full welding along the joint line for the weld to be created, and spacing when picking away the welding tool from the weld. In determining the weld quality, their values should be within a safe range during the welding process, to derive heat from friction, modifying the parameters of the process causes variation in force in the traverse and axial directions. The ability to measure forces and understand their relationship with welding parameters is essential to a successful FSW energy strategy. The analytical models presented in this study depict each welding phase as it occurs and can be applied to predict welding forces and the heat energies.

Since its inception, friction stir welding, FSW has been promising easy operation and environmental stewardship through contact friction between the tool and the weld part. The Aluminum alloy 2024-T351 was used in both working pieces. Six processes in FSW may include sticking, plunging into the welding pieces, half and full sliding, full welding along the joint line for the weld to be created, and spacing when picking away the welding tool from the weld. In determining the weld quality, their values should be within a safe range during the welding process, to derive heat from friction, modifying the parameters of the process causes variation in force in the traverse and axial directions. The ability to measure forces and understand their relationship with welding parameters is essential to a successful FSW energy strategy. The analytical models presented in this study depict each welding phase as it occurs and can be applied to predict welding forces and the heat energies.

The design of ferritic steel welding alloys to fit the ever expected properties of newly evolved steels is not a very easy task. It is traditionally attained by experimental trial and error, changing compositions and welding conditions until a sufficient result is established. Savings in the economy and time might be achieved if the trial process could be minimised. The present work outlines the use of an artificial neural network to model the elongation of ferritic steel weld deposits from their chemical compositions, welding conditions and heat treatments. The development of the General regression neural network (GRNN) models is explained, as is the confirmation of their metallurgical principles and precision.

In this paper wire cut electro discharge process parameters are optimized by using Taguchi method. Process parameters considered for the study are pulse on time, pulse off time and current. High Carbon high Chromium (HCHCr-D3) steel is high tensile strength alloy which is mostly used in cold dies and tooling application that where high degree and dimensional accuracy is required. HCHCr-D3 alloy steel plate of rectangular shape has been used for machining operation. Performance of wire cut electro discharge machine (WEDM) with a molybdenum wire has been measured by material removal rate (MMR) and surface roughness (SR). In Taguchi method L9 orthogonal array has been selected. The analysis of variance (ANOVA) has been used to determine effect of each parameter on material removal rate (MRR) and surface roughness (SR).

Aluminium alloys are applied in various industries because of their high strength to weight ratio. Aluminium Alloy 8011 is also lightweight, corrosion resistant and has high wettability. It is being currently used in various applications such as Storage tankers, Military equipment, high pressure containers, Air conditioning foil etc. The aim of this research is to study the effect of TIG welding using butt weld joint on microstructural and mechanical properties of Aluminium Alloy 8011. Here, we have designed an experiment using Bevel angle and welding current as variables in process parameters to study the tensile strength and hardness of weld joint of Aluminium alloy 8011. Gas flow rate, Electrode work piece distance, welding speed and welding voltage were kept constant. Then properties of samples were tested using Dye Test, Hardness test, Grain size analysis and Tensile Test. The results thus produced were then analyzed using Grey Relational analysis using Taguchi array.

The aim of the study of this method in Taguchi is to analyst a lathe machine operation while turning by some given
parameter. The parameter on which we will study is speed, feed, depth of cut, MRR, cutting force, feed force, thrust force. We
will use the Taguchi method to measure this type of parameter. Orthogonal arrays of Taguchi, the analysis of variance
(ANOVA) will help to measure the effect and error Confirmation tests with the optimal levels of cutting parameters are
administered so, for instance, the effectiveness of Taguchi optimization method. It is thus shown that the Taguchi method is
extremely suitable to solve the problem

In this research work the experimental investigation of TIG welding process on ss317 alloy pipe with different process
parameter viz. Welding current, voltage, and gas flow rate with L-9 orthogonal array design of experiment. Bending and Tensile
test are performed for all 9-test sample as an output parameter. Optimization of process parameter is done via ANOVA and
Taguchi method using MINITAB 18 software.
The optimum values of input parameter for tensile strength during TIG welding are 65A current,25V voltage, and 16 lit/s Gas
flow rate and for Bending strength the optimum input process parameter are 60A current, 25V voltage, and 16 lit/s Gas flow
rate. It has been observed that welding current affects the tensile strength maximum 77.92% followed by voltage 11.18 %. GFR
has minimum affect only 7.10% and It can be also observed that voltage affect the Bending strength maximum 37.129% followed
by GFR 32.21%. Welding current has minimum affect only 18.06%. The paper ends with a comparison of optimum process
parameter of Taguchi and ANOVA method.

The present investigation for optimization of MIG welding of Mild Steel is conducted to establish the influence of MIG welding process parameters on tensile strength and surface roughness. From the experimental results it is concluded that welding voltage is the main influencing parameter for tensile strength while welding speed is least influencing for it. In case of surface roughness, welding speed has major dominance while other parameters were less effective.

A solid state metal joining process known as Friction Stir Welding (FSW), is largely used to weld alloys of aluminium.
The influence of the various parameters associated with the process such as speed of rotation of the tool, speed of welding and
angle the tool makes with the horizontal surface of the workpiece or tilt angle on the weldability of AA7050 is studied in this
paper. The study was performed on VMC (i.e. Vertical Milling Machine and Universal Testing Machine was interrogated to find
the output parameters. A convincing result was achieved wherein the above factors mentioned are strongly influencing the weld
strength. Implementation of Taguchi method to optimize the results was conducted. ANOVA analysis revealed the amount of
contribution each factor have with the improvement in the weld strength. .Signal to Noise, ratio (S/N ratio)) gave the optimal
parameters which largely influenced the weldability.
Taguchi method validated the test results and showed that the performance of the welded joint is improved.

Friction Stir Welding (FSW) is a solid state welding process which produces welds due to the compressive force contact of work pieces which are either rotating or moving relative to each other. The heat required to join different specimens is generated by heating due to friction at the interface. Application of Friction Stir Welding in aerospace industries is very broad. Rolls-Royce now uses friction welding processes for its modern Trent aero engines that drive the Airbus A380 and the Boeing 787.In this paper, Friction Stir Welding of various dissimilar metals are reviewed. The microstructure, hardness and flow characteristics are also reviewed.

This study examines the social context of workplace violence and risk avoidance in the context of legal regulations meant to reduce harms associated with the industry. Ethnographic research, including 18 months of extended field observations and interviews with 190 female sex workers, is used to illustrate how sex workers in Tijuana, Mexico, experience and manage workplace violence. Multiple subthemes emerge from this analysis, including deciding where to work, working with a third party, avoiding theft, and dealing with police. These findings support the idea that the risk of violence is part of a larger "hierarchy of risk" that can result in a "tradeoff" of harms.

Thermoplastic materials are now easily joined by friction stir welding. Joining of thermoplastics in friction stir welding which is
based on frictional heat generated through contact between a rotating tool and the work piece. The determination of welding
parameters plays an important role in weld strength. In friction stir welding of thermoplastics, traditional tools form a slit on the
backside of welded specimen which leads to root defect causes  poor tensile strength. Due to the high transparency of this
polymer, it was to possible to analyse easily the morphological changes induced by the welding process on it.In this investigation
the welding parameters studied were the tool rotation speed which varied between 800 and 1200 (rpm), transverse speed which
varied between 40 and 200 (mm/min), axial force ranging from 1 to 5 (KN).An attempt was made to join the polypropylene plate
of 5 mm thickness with different tool profiles (square, cylindrical and triangular threaded pin profile). The quality of the joint
was evaluated by means of tensile strength and micro structural analysis.

This paper describes the first part of the
development of a non-linear finite element
simulation of the friction stir welding process;
it is concerned with thermal analysis. A
transient, three dimensional, non-linear thermal
model with moving heat source was
developed. Also a steady-state, three
dimensional, non-linear fluid-thermal model
with stationary heat source was developed.
Differences of results for both models were
discussed. Results of both models were
compared with experimental work. Transient
thermal model results appear to be more
reliable as compared to the CFD approach.