Figure 6(c), shows the effect of axial force on joint efficiency of frictionstir welded AA7075- 10%wt.SiC composite joints. The lowest strength was obtained at axial load of 5 kN and 9 kN. The joint efficiency of composite joint was increased with increase in axial load up to a maximum load of 7 kN. Further increase in axial load decreased the tensile strength of the joint. During the FSW process, the rotation of tool produces a large amount of heat input which brings the metal to become very hot and plastic state. The axial force is more responsible for the plunge depth of the tool pin into the work piece . The joining of materials depends on the extrusion process by axial force and the rotation of tool pin which propeled the plasticized material. At a lower axial force (5 kN), the lowest frictional heat is generated which is not sufficient to generate a adequate plastic state. At a higher axial force (9 kN) the plunge depth of the tool into the work piece is higher which drastically decreases the strength [Ref 16]. The joint fabricated with an axial force (7 kN) produced a finer grain structure with uniform distribution of reinforcement particle in the stir zone and resulted higher joint efficiency value. Hence sufficient axial force is required to form good weld.
Avinash P et al  to investigate the mechanical and structural properties of AA7075 T6 and AA2024 T3 dissimilar aluminium alloys, with thickness ratio 1.3, since both AA2024 T3 and AA7075 T6 are not weld able by fusion weldingprocess, FSW process is used to weld both of these dissimilar alloys. Defect-free, tailor weld blanks were produced on the plates of AA7075 and AA2024 T3 having thickness of 6.5mm and 5mm respectively. The processparameters employed in this study include the tool rotation and travel speeds. The FSW tool employed in this study was made using AISI H13 tempered steel with square pin profile having pin diameter of 5mm, concavity at pin start of 1mm and pin length of 4.85mm. The welded plates have been characterized for their mechanical and metallurgical properties. The effects of tool rotational speed and the welding speed on the joint performance were discussed. Experimental result shows a sound weld has been produced at medium rotational speed (1000rpm) and lower travel speed (80mm/min), uniform weldments
The FSW window for producing sound welds in AMCs is narrower compared to unreinforced alloys due to the presence of ceramic particles . A large number of trial welds were carried out to fix the working ranges of all selected processparameters. Each trial weld was inspected for smooth bead appearance and cross sectioned to verify the presence of defects such as pin hole, tunnel and worm hole in the weld zone. The limits of each process parameter were decided upon yielding defect free welds. The upper limit of a process parameter was coded as +2 and the lower limit was coded as –2 for the convenience of recording and processing experimental data. The coded values for intermediate values were calculated using the following relationship.
Surface metal matrix composites (SMMC) exhibit a unified combination of high tribological properties at the surface and toughness of the interior bulk metal when compared with both Metal Matrix Composites (MMC) and monolithic materials . Mishra et al.  explored the potential of FSP technique in fabricating silicon carbide (SiC) reinforced surface composite layer on aluminum (Al) 5083 alloy. Since then, a variety of surface composites based on magnesium, copper, titanium and steel have been
engineering applications require materials with a wide range of properties that are difficult to meet using monolithic material structures . It has been noted that metal matrix composites (MMCs) offer such tailor-made property combinations required in a wide range of engineering applications . In particular, composites have enhanced significant tribological properties to meet the needs of the important surface engineering field. With the reinforcement of ceramics particles, the surface properties of the material are improved significantly. The large application of composites to the aerospace, automotive, defense industry, etc. has influenced new researchers in the development and design of manufacturing techniques [3,4]. Recently, in surface engineering the surface metal matrix composites are also being fabricated through various methods like plasma spraying , cold spraying , laser melting [7–10], cast sinter [11,12], etc. Also the bulk metal matrix composites are produced by using the conventional methods like stir casting , powder metallurgy , mechanical alloying , etc. These fabrication techniques have many disadvantages such as reinforcement agglomeration, formation of detrimental phases, and interfacial reactions due to processing above melting point temperature [16,17]. Thus to overcome these disadvantages the researchers look for the other novel techniques. The frictionstir-processing (FSP) technique overcomes many disadvantages due to processing below the melting point temperature of base alloys. Initially, R.S. Mishra et al. proposed FSP technique and have fabricated the Al-silicon carbide (SiC) ex-situ surface composites . Then this solid state and eco-friendly technique became more popular among researchers and led to numerous research works on surface composites fabrication using FSP.
Successful studies on dissimilar materials by Khodir and Shibayanagi  show the improvement in the joint made in the FSW of dissimilar AA2024 and AA7075 aluminum alloys by varying the welding speed and fixed location of the base metals. It was found that the mechanical properties of the welded joint are improved at a welding speed of 1.67 mm/s and when placing AA2024 on the advancing side . Ravikumar and Rao  studied the macro and micro structural characteristics of the dissimilar FSW of an AA7075-T651 and AA6061-T651 butt joint which presents better mixing of both materials and good weld strength at 900 rpm, 90 mm/min with a tapered cylindrically threaded tool . Ghosh, Kumar  researched the optimization of the A356 and AA6061 FSW parameters by varying the tool rotational speeds of 1000–1400 rpm and traversing speeds of 80–240 mm/min that are responsible for the change in total heat input and cooling rate during the FSW process. Joint improvement in the weld strength was produced at the lowest tool traversing and rotational speeds, more than 98% of the 6061 alloy .
The hardness test technique for Rockwell involves a diamond cone or hardcore steel ball penetration of the sample material. On a small initial load F0 (Figure 4A) generally 10 kgf the indenter is fed onto the sample accordingly. When stability is achieved, an indicating unit that follows the indenter's penetration and thus reacts to updates in the indenter's depth of penetration is fixed to a datum position. A further large load is applied while the preliminary low load continues with a rise of penetration. (Fig 4 B). The additional major load will be removed when the stability has been reached again, but the initial minor load will still be preserved. The elimination of the extra major load enables partial retain, thus lowering the penetration depth (Fig 4 C). For calculating the Rockwell hardness numbers, continuous rise in penetration depth arising from use and withdrawal of the added significant load is
943 | P a g e method like Gas metal Are welding. The quality of the weld in FSW is determined by the processparameters tool rotation speed, tool traverse speed and plunge speed, depth of tool penetration and axial force on the shoulder  –. Quality weld can be obtained by precise control of these above parameters. Mechanical properties in weld zone are affected by frictionstir processing due to the rotation of the tool .
However, several aluminum joints formed by FSW were studied by several researchers, Optimization of the FSW factors for aluminium alloy AA5083 used normally in the automotive, marine, construction and structural industries, has not yet been investigated with aid of response surface methodology (RSM). RSM is beneficial in improving an appropriate ballpark stature for the well-designed association between the independent input factors and the output factors that may idealize the quality of the joints (Manonmani et.al., 2005). This has been proved by several researchers (Balasubramanian et al.,2008; Palani and Murugan, 2007; Palani and Murugan, 2006; Hung et.al., 2012; Gunaraj and Murugan,1999) studied the chief problem noted in the production of pipes by the submerged arc welding operation related to the selection of the optimal interaction of input factors for attaining the desired qualities of weld. They proposed the settlement by the improvement of mathematical models through effective and strategic planning and the execution of experiments by RSM. Therefore, in this investigation, an attempt has been made to study the effect of TRS, and WS factors on the characteristics of dissimilar 6061-7075 Al alloys joint, so that the effectiveness of each factor on the tensile strength and optimal input factors of FSW operation for 6061-7075 joints could be specified.
desired is clearly on display and it is one of the goals of this manuscript to recreate this affect by varying different weldingparameters. This provided a prediction to create weldingparameters that can be seen in Table 3.1.1 that would result in the desired output instead of trial and error. This dataset varies the forge force similar to the original experiment discussed in Chapter 1. It can be seen that a Rotation per Inch (RPI) range of 14 to 21 can be used to recreate the desired bow-tie effect. With this knowledge in hand, similar process variables were developed based off of this fact. For this experiment, the RPI was chosen to be in the range of 13 to 25 to encompass a larger range as it was noted that the bow-tie effect would diminish under lower travel speeds, but this data was inferred from a smaller data range. A middle point between the two extremes was selected to see if the insensitive point could be recreated. The complete results in this experiment will be displayed with respect to Force/RPM instead of RPM/IPM since the travel speed was varied instead of the forge force.
ABSTRACT: This paper is exclusively focused on the preparation procedure of Al-SiCcomposite and testing the prepared sample composite for various mechanical properties like tensile strength, hardness, impact strength along with the micro structure evaluation of the composite at the welded portion. The sample composites prepared is of two different compositions, one made with pure aluminium and 10% SiC base and the other with 15% SiC base. Also the properties are checked on a welded and non-welded samples of each type.
Taguchi method is an powerful problem solving tool, which can improve the performance of the process, product, design and system with a significant slash in experimental cost and time. This technique that combines the experimental design theory and quality loss function concept has been applied for carrying out strong design of processes and products and solving many critical problems in manufacturing industries. Further, this method finds the most influential parameters in the entire performance. The optimum weld parameters found from the Taguchi concept are insensitive to the change in environmental condition and other noise factors. In DOE number of trials increases when the number of processparameters increase. To solve this difficulty, the Taguchi technique utilizes a special design of orthogonal array to find the overall process parameter space with a few number of experiments only. Taguchi has developed three important signals to noise ratios (S/N) (i.e. the nominal- the-better, lower-the-better and the larger-the-better) depending on the of the quality characteristics. The S/N ratio for each of process parameter is calculated based on S/N analysis. Regardless of the classification of the quality characteristics, a larger S/N ratio relates to better quality characteristics. Therefore, the largest S/N ratio indicates to the optimal level of process parameter. Statistical analysis of variance (ANOVA) can be performed to find the significant process parameter. A confirmation test is conducted to validate the predicted optimal levels found out from the analysis.
number 4 with a spindle speed of 1800Rpm,travel speed 50mm/min & plunge speed is 20mm/min.Research Gap: Above researcher is not done with maximum tensile strength (164.5MPa) is achieved in 900Rpm of rotational speed and 20mm/min of welding speed and not researched over increase the rotational speed for fixed welding speed or increasing welding speed for fixed rotation speed .
Abstract: Frictionstirwelding has proven to be the most promising solid state joining process. It can be used to get high weldability in joining of high strength aerospace aluminium alloys and other metallic alloys which used to be low with traditional fusion weldingprocess. This paper emphasises on finding the optimum process parameter for frictionstirwelding of dissimilar aluminium alloy AA6061 to AA5183 using multi criteria decision making method (MCDM). Frictionstirwelding was done at different tool rotational speed and transverse velocity and mechanical properties such as tensile strength, percentage elongation and hardness were studied for each weld specimen. Finally optimization was done using TOPSIS (Techniqueof Ordered Preference by Similarity to Ideal Solution). The result revealed that the tool rotational speed of 1200 rpm and welding speed of 80mm/min are the optimum weldingparameters.
Frictionstir spot welding (FSW) is a relatively novel welding technology, which has caught the interest of automobile, ships and aeronautic industrial sectors due to its many advantages and saving large industrial potential. This paper presents the prediction of welding strength at variable welding parameter used a frictionstir spot weld joints obtain through Artificial Neural Networks (ANN). Experiments were conducted by varying the input variable weldingparameters such as rotational speed, plunge depth, plunge rate and dwell time, which create a key role in deciding the weld quality. A full design (trials) was used through the experimental design. ANN is solving obtained by two kinds such as M coding and nftool in Mat-lab.
produces a solid bond between the workpieces to be joined. The pattern of material ow depends upon the FSW processparameters, which in turn determine the quality of the joint produced. The parameters showing dominance in aecting the performance characteristics of aluminium alloy joints fabricated using FSW are rotational and transverse speeds of the welding tool; however, other parameters like tool shoulder diameter, tilt angle, pin prole, and hardness of tool material also have considerable impact [3-5]. FSW is dierent from conventional joining methods in terms of temperature rise during the process, which is lower than the melting point of the workpiece materials in it, resulting in avoidance of many solidication defects that otherwise occur during the conventional welding techniques . FSW is considered to be one of the most epochal inventions in the past decades as it has all the potential to join light structural materials like aluminium and its alloys, which are dicult to join using fusion welding methods [7,8].
Scrolls are the most commonly observed shoulder feature. The typical scrolled shoulder tool consists of a flat surface with a spiral channel cut from the edge of the shoulder toward the centre (Image 3.1). The channels direct deformed material from the edge of the shoulder to the pin, thus eliminating the need to tilt the tool. Removing the tool tilt simplified the friction stirring machine design and allowed for the production of complicated nonlinear weld patterns. Concave shoulder tools also have a tendency to lift away from the work piece surface when the tool travel speed is increased. Replacing the concave shoulder with a scrolled shoulder reduces the tool lift and increases the welding speed. An additional advantage of the scrolled shoulder tool is elimination of the undercut produced by the concave tool and a corresponding reduction in flash. Also, because the tool is normal to the work piece, the normal forces are lower than concave shoulder tools, which must apply load in both the normal and transverse directions to keep the shoulder in sufficient contact. In addition, the material within the channels is continually sheared from the plate surface, thereby increasing the deformation and frictional heating at the surface . Scrolled shoulder tools are operated with only 0.1 to 0.25 mm (0.004 to 0.01 in.) of the tool in contact with the work piece; any additional work piece contact will produce significant amounts of flash. If the tool is too high (insufficient contact), the shoulder will ride on a cushion of material that will smear across the joint line and make a determination of weld quality difficult . Thus, use of the scrolled shoulder requires more positional care than the concave shoulder. The limitations of scrolled shoulder tools include the inability to weld two plates with different thicknesses, an inability to accommodate for work piece thickness variation in the length of the weld, and welding of complex curvatures (especially tight curvatures). Scrolled shoulder tools can weld two plates of different thicknesses, but some amount of material from the thicker plate is expelled in the form of flash.
Purpose. The study is aimed at improving the procedure for determining the optimum radius of the shoulder of a special tool for frictionstirwelding (FSW) of aluminum alloys and its change depending on the variations of base metal thickness. Methodology. The frictionstirweldingprocess was carried out on specially designed equipment. The material for the studies were 1.85 mm thick plates made of aluminum alloy AMg3 with a chemical content of alloying elements within the range of the brand composition. The temperature in the welding zone and the pressure from the tool on the edges of the welded joint were determined using a specially designed research stand. The press- ing force of the tool to the base metal during welding was measured with a dynamometer type DC-0.1 with the indi- cator head. Findings. During the research, the degree of metal heating and the quality of the welded joint formation were determined at various ratios of the rotation frequency of the working tool and the normal pressure to the join- ing edges. The research allowed determining the influence of FSW processparameters on the temperature of metal heating in the action zone of the working tool shoulder. Originality. The experimental studies allowed to determine the effect of the working tool rotation speed and the magnitude of its pressure on the welded metal during welding on the temperature in the weld zone. Increasing the tool rotation frequency allows to reduce pressure of the working tool during welding, which results in more efficient and high-quality weldingprocess. It has been established that it is possible to obtain better welded joints at a temperature of about 0.7 Tm and to determine the optimal temperature range in the welding zone. Practical value. The study resulted in determination of the conditions for achieving the permanent softening effect during frictionstirwelding and the optimum temperatures in the welding zone for the tested alloy. The main technological parameters of the working tool are calculated and their influence on the genera- tion of thermal energy in the welding zone is determined. The thermal analysis of the weldingprocess resulted in development of the procedure for determining the technological parameters of the working tool and its rotation fre- quency depending on the weld metal thickness.
Validation was conducted with the developed analysis model for a low traverse speed of 1 mm/s to a high speed of 20 mm/s, comparing the analysis data with experiment results. Figure 14 shows the validation result for tool temperatures, and Figure 15 shows for the welding forces. Both experiment and FEM data were acquired 1.0 second after the start of tool traversing. The tool-tip tempera- tures were almost the same between the experiment and analysis results. The shoulder temperatures of analyses and experiments had the same tendency with the traverse speed, though the analysis results became about 30˚C to 40˚C higher than the experiment ones. The analysis results of traverse force had good agree- ment with the experiment results. Then, the developed analysis model is able to simulate FSW process at a wide range of tool traverse speeds. This validation in- dicated that developing a FSW analysis model that calculate reasonable tool temperatures and processparameters needs accuracy of its thermal boundary conditions, especially heat transfer coefficient at the workpiece bottom.
FrictionStirWelding (FSW) is a solid state weldingprocess in which the relative motion between the tool and the work piece produces heat which makes the material of two edges being joined by plastic atomic diffusion. This method relies on the direct conversion of mechanical energy to thermal energy to form the weld without the application of heat from conventional source. The rotational speed of the tools, the axial pressure and welding speed and the (weld time) are the principal variables that are controlled in order to provide the necessary combination of heat and pressure to form the weld. These parameters are adjusted so that the interface is heated into the plastic temperature range (plastic state) where welding can take place. During the last stage of weldingprocess, atomic diffusion occurs while the interfaces are in contact, allowing metallurgical bond to form between the two materials. The functional behaviour of the weldments is substantially determined by the nature of the weld strength characterized by the tensile strength, metallurgical behavior, surface roughness, weld hardness and micro hardness. In this project an attempt is made to determine and evaluate the influence of the processparameters of FSW on the weldments. The Vickers hardness, tensile strength and radiography are considered for investigation by varying tool speed, tool feed and maintaining constant depth of penetration of weld. Experiments were conducted on AA6351 Aluminium alloy in a CNC Vertical Machining Centre. The output factors are measured in UTM, Vickers hardness tester and Radiography equipment. Results show strong relation and robust comparison between the weldment strength and processparameters. Hence FSW process variable data base is to be developed for wide variety of metals and alloys for selection of optimum processparameters for efficient weld.