Influence Of Tool Rotational Speed Research Articles

Finite Element Simulation of Friction Stir Welding of Inconel 718 to Nimonic 80A

This paper presents results of simulation of friction stir dissimilar welding of 5 mm thick, Nickel-based super-alloys, Inconel 718, and Nimonic 80A using Abaqus software. Four different trials were done to understand the influence of tool rotation speed on temperature distribution in weld zone while travel speed remains constant. The temperature in the weld zone was found to increase with the increase in tool rotation speed and travel speed. The temperature on the advancing side of the tool was higher than that of the retreating side. The tensile strength of weldment was found, by simulation, to be 25% more than that of base metal, Inconel 718. This may be due to grain refinement and dynamic recrystallization during FSW. The simulated bend test revealed an adequate level of ductility of weldments.

Investigation into Mechanical Properties and Sliding Wear Behavior of Friction Stir Processed Surface Composite Material

One of the different and pioneering solid‐state techniques, friction stir processing (FSP), is employed for the production of surface composites. In this research, the matrix selected was copper‐nickel (CuNi) with hard boron carbide particle as reinforcement. The objective of the current research work is to produce reinforced 90/10 copper‐nickel surface composites reinforced with B4C fabricated via FSP. The influence of tool rotational speed on macrostructure, microstructure, grain size analysis, microhardness, and wear studies of friction stir processed (FSPed) CuNi/B4C surface composites was assessed. For high rotational speed (1400 rpm) of stir tool, the modified surface area found is a maximum of 44.4 mm2 with uniform dispersion of hard particle reinforcement. The presence of hard particle in the surface area is revealed through the electron imaging and the spectroscopic results. Spectra mapping shows the uniform distribution of hard particle over the FSPed area, and the evidence is obtained with XRD analysis. From the experimentation, it is interesting to report that the reinforcements have decreased the surface hardness for an increased rotational speed of stir tool. The hardness recorded for minimum rotational speed is 223 HV which has gradually decreased to 178 HV for 1300 rpm. It has directly influenced the wear rate of modified FSPed, as hardness is directly proportional to wear behavior. The worn surface and fractured morphology of the CuNi/B4C surface composites were also studied using Field Emission Scanning Electron Microscope (FESEM).

An investigation on the effects of tool rotational speed and material temper on post-ISF tensile properties of Al2219 alloy

Incremental Sheet Forming (ISF) is a novel cold sheet forming process. This study aims at investigating the influence of tool rotational speed on post-ISF tensile properties of two tempers of Al2219 alloy namely Al2219-O and AA2219-T6. The rotational speeds are changed from 50 to 2000 rpm while keeping the other parameters fixed. The sheets are formed into the frustum pyramid of fixed wall angle of 45°. It is found that post-ISF tensile strength of both tempers experiences a drop with increasing tool speed. The ultimate strength (UTS) of O-temper decreases from 236 to 153 MPa and its yield strength (YS) decreases from 171 to 81 MPa. Similarly, the ultimate strength of T6 temper reduces from 306 to 170 MPa and its yield strength reduces from 239 to 110 MPa. Moreover, upon forming, the O-temper generally endures a gain while the T6 temper endures a loss in strength. These properties show strong correlation with the forming induced temperature, particles density/size and grain size. It is noticed that friction heating rate at the tool sheet interface increases with the spindle speed thereby reducing the density of second phase particles and increasing the size of particles and grains. These microstructural variations in turn cause corresponding reductions in the yield and tensile strengths of material. These results identify the role of spindle rotation in ISF and thus will serve as a guideline in process design to achieve desired post-ISF properties of the chosen alloys.

Influence of tool rotational speed on local microstructure, mechanical and corrosion behavior of dissimilar AA2024/7075 joints fabricated by friction stir welding

In this investigation, the local microstructure evolution, mechanical properties and corrosion behavior of the dissimilar friction stir welded AA2024/7075 joints were evaluated as a function of rotational speed. The results showed that the rotational speed mainly affects the local microstructure and performance of the dissimilar joints. Fine equiaxed grains are formed in the nugget zone (NZ). The average grain size decreases in the sequence of shoulder zone (SZ), center zone (CZ) and bottom zone (BZ), and increases with increasing rotational speed. Different types of shear textures are formed at different positions of the NZ, which vary with the rotational speed. The maximum tensile strength of 411.4 MPa is acquired in the joint at 950 rpm, with the welding efficiency of about 87.6 % relative to the AA2024 base material. The fracture position of all the joints is in the lowest hardness zone during tensile tests. Higher corrosion current density presents in the welded zone, which results from the formation of galvanic corrosion. The corrosion behavior of the welded zone is influenced by rotational speed and higher corrosion resistance can be acquired in the joint fabricated at 950 rpm due to the appropriate precipitates density and size.

Influence of tool rotational speed on the mechanical and microstructural properties of AISI 316 Austenitic stainless steel friction stir welded joints

Fabrication of steel joints using fusion welding technique will result in defects like hot cracking, and heavy residual stresses along with coarse microstructural features in the weldments. To overcome these problems, friction stir welding (FSW) technique was employed to fabricate steel joints. Tungsten based alloy tool is used in this investigation to withstand high dynamic frictional forces at elevated temperature generated during welding. Tool shoulder diameter of 25 mm, pin diameter of 3 mm and pin length 2.9 mm was employed to carry out the friction stir welding on SS316 steel plate of 3 mm. Sound joints produced at a constant welding speed of 40 mm min−1, axial load of 15 kN at different tool rotational speed of 600 rpm and 700 rpm. In accordance with ASTM standards, Tensile, Compression, Micro hardness and impact tests were carried out to assess the mechanical properties of weld joints and the base metal. Mechanical testing results showed that tensile and hardness of the welded material was improved in compared with base metal. However, the impact strength of the welded metal is reduced. Furthermore, the base metal and welded metal were subjected to study microstructural analysis using optical and scanning electron microscopy. EDS and XRD analysis were also carried out on welded zone to understand about the formation of new phases in weld zone and it is surroundings.

Influence of tool rotational speed on the properties of friction stir spot welded AA7075-T6/Al2O3 composite joint

The growing importance of Aluminium alloys in automobiles and aerospace applications provides the implementation of composite materials and promising joining method like Friction Stir Spot Welding (FSSW). In this research, Al2O3 nanoparticles reinforced FSSW is carried out on 7075-T6 Aluminium alloy and the influence of tool rotational speed on mechanical properties is studied. The base metal of thickness of 2 mm is spot welded using a threaded cylindrical profile tool with four different tool rotational speeds varying between 900 rpm and 1700 rpm, where volume of Al2O3 is being unchanged. The results of mechanical tests show that the sample made with a tool rotational speed of 1300 rpm has a better weld of good strength. Moreover, the result from Field Emission Scanning Electron Microscopy also evidences the uniform distribution of Al2O3 nanoparticles in the weld region which causes the improved strength. Also observed that the lower and higher tool rotational speeds from the selected range do not result homogeneous distribution of nano fillers in the weld nugget.

Investigation of the mechanical properties of friction stir welded PA6-based polymer nanocomposite and optimizing experimental conditions

The newly fabricated two-phase composite of polyamide-6/nitrile butadiene rubber reinforced with halloysite nanotubes was welded by heat-assisted friction stir welding. The welding process was carried out via a heating system placed inside the stationary shoe-shoulder under different process conditions and materials to achieve sound joints. Influence of tool rotational speed, tool traverse speed, and HNTs content as the three input parameters on mechanical properties has been investigated using response surface methodology. Analysis of variance was utilized to establish the significance of independent variables on welding overall quality characteristics. The multi-response optimized variables were found to be as follows: rotational speed = 900 (RPM), traverse speed = 14 (mm min−1), and HNT = 6.72%. Under these conditions, the maximum values attained for tensile strength, Young’s modulus and impact strength were 59.1 (MPa), 1416.3 (MPa) and 124.1 (J m−1), respectively. Optimal results have been validated through confirmation experiments. Morphological and microstructural characterization of the fractured surface of samples using scanning electron microscopes revealed that the increase of shear stress due to tool stirring action as well as the addition of halloysite nanotubes improves the interfacial interactions and produce fine rubber phase of PA6/NBR composites.

Influence of tool rotational speed on microstructural characteristics of dissimilar Mg alloys during friction stir welding

Dissimilar friction stir welding of the AZ80A Mg alloy as the advancing side and the AZ91C Mg alloy as the retreating side was carried out at a constant feed rate of 75 mm/min using a taper cylindrical pin profiled tool at different tool rotational speeds. Defect free welds were produced in the 700–900 rpm rotational speed range. During friction stir welding, extrusion of metal took place in the advancing side and this extruded material was dynamically recrystallized and redeposited on the retreating side. This experimental investigation revealed that friction stir welding leads to the formation of comparatively finer sized grains on the retreating side of the thermo-mechanically affected zone compared to grains in the thermo-mechanically affected zone on the advancing side. Moreover, the heat affected zone of AZ80A possessed fine sized grains compared to the heat affected zone of AZ91C. Additionally, increasing tool rotational speed influenced the tensile strength of the fabricated joints.

Influence of tool rotation speed on microstructural characteristics and mechanical properties of friction stir welded AA2014-T6 aluminium alloy

Friction stir welding (FSW) is a promising solid-state welding process for precipitation hardening and high strength aluminium alloys. An experimental and theoretical investigation was carried out to check the significance of tool rotation speed on microstructural characteristics and tensile properties of high-strength alloy AA2014. FSW joints were made with varying tool rotation speed from 1,100 rpm to 1,900 rpm with an equal increment of 200 rpm, while the other parameters such as welding speed, shoulder diameter and tool tilt angle were kept constant. The strength of FSW joints was correlated with microhardness, microstructure and fractographs. The joint fabricated with the tool rotation speed of 1,500 rpm, welding speed of 50 mm/min, shoulder diameter of 6 mm and tool tilt angle of 1.5° exhibited superior strength (376 MPa) than the other joints. It could be achieved by the balanced flow of material and defect-free in the stir zone.

Influence of tool rotation speed on microstructural characteristics and mechanical properties of friction stir welded AA2014-T6 aluminium alloy

Friction stir welding (FSW) is a promising solid-state welding process for precipitation hardening and high strength aluminium alloys. An experimental and theoretical investigation was carried out to check the significance of tool rotation speed on microstructural characteristics and tensile properties of high-strength alloy AA2014. FSW joints were made with varying tool rotation speed from 1,100 rpm to 1,900 rpm with an equal increment of 200 rpm, while the other parameters such as welding speed, shoulder diameter and tool tilt angle were kept constant. The strength of FSW joints was correlated with microhardness, microstructure and fractographs. The joint fabricated with the tool rotation speed of 1,500 rpm, welding speed of 50 mm/min, shoulder diameter of 6 mm and tool tilt angle of 1.5° exhibited superior strength (376 MPa) than the other joints. It could be achieved by the balanced flow of material and defect-free in the stir zone.

Influence of Tool Rotational speed and Pin Profile on Mechanical and Microstructural Characterization of Friction Stir Welded 5083 Aluminium Alloy

A study was made of weldability of 4mm-thick Aluminium alloy 5083 plates using friction stir welding. The plan of experiments was prepared based on abilities of universal milling machine. The tool rotational speeds of 900r/min, 1120r/min, 1400r/min and 1800r/min, the welding speed of at 40mm/min were taken. The tool pin geometries are taper threaded profile tool and conical taper profile tool. Samples for microstructure analyses, Vickers micro-hardness measurements, and tensile-testing samples were prepared. It was observed that the better mechanical properties were achieved at moderate tool rotational speed, and equi-axed grains obtained at conical taper tool profile as compared with taper threaded tool. Analysis is made with the Samples for microstructure analyses, Vickers micro-hardness measurements and tensile-testing samples were prepared.

Influence of Tool Rotational Speed on the Formation of Friction Stir Processing Zone in Cast Zk60/SiCp Magnesium Alloy Surface Composites

A Cast ZK60 magnesium alloy plays a tremendous role in the fabrication of lightweight structural materials. However, the low surface properties, like low friction and wear resistance, restricts the magnesium alloy during the structural application. Conventionally, the surface properties of magnesium alloys were improved using various processing methods like high-energy electron beam irradiation, plasma-transferred arc surfacing, and high-energy laser melt treatment. However, the above processes are involved in melting the magnesium material, which results in defects and detrimental metallurgical phase formation. Friction Stir Processing (FSP) can overcome this problem since the processing is done in the solid state. However, FSP often appears to be a significant applicant on the magnesium plate to attain successful fabrication of surface metal matrix composites. In this investigation, an attempt at FSP zone formation in magnesium alloy has been made in order to understand the influences of rotational speeds ranging from 700 to 1,100 r/min. From this investigation, it is found that the FSP made by using the high tool rotational speed of 900 r/min and 10 mm/min exhibited higher hardness and uniform particle distribution. This may be attributed to the grain boundary and dispersion strengthening.

Influence of Tool Rotational Speed on the Mechanical and Microstructure Properties of Friction Stir Welded Al-B4C MMCs

Friction Stir Welding (FSW) is a solid state joining technique developed to join high strength aluminum alloys and different ceramic reinforced Metal Matrix Composite (MMCs). FSW produces sound welds in MMCs without any detrimental reaction between reinforcement and matrix. In this work, AA6061-10 wt.% B4C Metal Matrix composites (MMCs) are joined using Friction Stir Welding (FSW) process. Different tool rotational speeds are developed to weld the MMCs and the effect of tool rotational speed on mechanical and metallurgical properties of the weldments has been investigated. The different tool rotational speeds, i.e. 800 rpm, 900 rpm, 1000 rpm, 1100 rpm and 1200 rpm are used to obtain defect free welds. It has been observed that, the joint welded with 1000 rpm of tool rotational speed exhibited better mechanical properties compared to the other tool rotational speeds. Weld nugget has finer grains compared to other weld zones and B4C particulates are homogeneously present in Al matrix both in weld and parent metal.

Friction stir processing of Al6061-SiC-graphite hybrid surface composites

ABSTRACTFriction stir processing (FSP) of Al6061-SiC-Graphite hybrid composites is studied in detail via force analysis, spectroscopic, microstructural and indentation studies. Effect of various tool rotational speeds was assessed, and the axial force variation was monitored. The presence of graphite as a reinforcement influences the axial force fluctuations due to its flaky nature and high thermal conductivity. Variation in microstructure at different tool rotational speed is studied using scanning electron microscope. The tool rotational speed has a significant influence on the area of FSP zone, fragmentation and depth of penetration of particles, dispersion of agglomerates and grain refinement of the matrix material. Spectroscopic characterization of the processed samples was done using Raman analysis and X-Ray diffraction studies. A noticeable change in intensity and shift in the respective Raman peak positions were observed, indicating residual stresses and various disorders in the crystal structure of the reinforced particles. Influence of tool rotational speed and existence of SiC and Graphite particles on the mechanical properties were further evaluated using nano indentation testing. The hybrid composite shows the combination of best and uniform mechanical properties at an optimum set of processing parameters.

Friction stir forming of dissimilar grade aluminum alloys: Influence of tool rotational speed on the joint evolution, mechanical performance, and failure modes

Friction stir forming (FSF) is a solid-state, eco-friendly spot welding technique primarily applied for lap joining dissimilar sheet metals. The details related to the process are scarce in literature. The present work explores the potential of the FSF process for joining dissimilar grade alloys of same metal, namely aluminum. The effect of tool rotational speed on the joint formation and mechanical performance of FSF joints between AA5052-H32 and AA 6061-T6 sheets is studied through systematic experimentation and macrostructure analysis. Hardness distribution across the joint, joint morphology, and failure modes at varying rotational speeds are also presented. The tool rotational speed shows significant effect on the mechanical performance results, zones formed within the joint, and hardness distribution across the joint. Maximum lap shear strength, about 6 kN, obtained in the present work is superior than that of joints fabricated on same material combination with other friction-based joining technologies. The lower and medium tool rotational speeds, between 500 and 1500 rpm, are the best choices for fabricating FSF joints for the materials used. Macrostructure analysis revealed that at lower tool rotational speed ( 1500 rpm), localized stir zones are distributed over the cross-section. Friction stir form samples showed an inverted “W”-shaped hardness profile over the cross-section, and the joint morphological features are independent of the tool rotational speed. Failure modes such as partial bond delamination, tear-off, and pull-out occur randomly and have no systematic correlation with the tool rotational speed.

Influence of Tool Rotational Speed and Post-Weld Heat Treatments on Friction Stir Welded Reduced Activation Ferritic-Martensitic Steel

The effects of tool rotational speed (200 and 700 rpm) on evolving microstructure during friction stir welding (FSW) of a reduced activation ferritic-martensitic steel (RAFMS) in the stir zone (SZ), thermo-mechanically affected zone (TMAZ), and heat-affected zone (HAZ) have been explored in detail. The influence of post-weld direct tempering (PWDT: 1033 K (760 °C)/ 90 minutes + air cooling) and post-weld normalizing and tempering (PWNT: 1253 K (980 °C)/30 minutes + air cooling + tempering 1033 K (760 °C)/90 minutes + air cooling) treatments on microstructure and mechanical properties has also been assessed. The base metal (BM) microstructure was tempered martensite comprising Cr-rich M23C6 on prior austenite grain and lath boundaries with intra-lath precipitation of V- and Ta-rich MC precipitates. The tool rotational speed exerted profound influence on evolving microstructure in SZ, TMAZ, and HAZ in the as-welded and post-weld heat-treated states. Very high proportion of prior austenitic grains and martensite lath boundaries in SZ and TMAZ in the as-welded state showed lack of strengthening precipitates, though very high hardness was recorded in SZ irrespective of the tool speed. Very fine-needle-like Fe3C precipitates were found at both the rotational speeds in SZ. The Fe3C was dissolved and fresh precipitation of strengthening precipitates occurred on both prior austenite grain and sub-grain boundaries in SZ during PWNT and PWDT. The post-weld direct tempering caused coarsening and coalescence of strengthening precipitates, in both matrix and grain boundary regions of TMAZ and HAZ, which led to inhomogeneous distribution of hardness across the weld joint. The PWNT heat treatment has shown fresh precipitation of M23C6 on lath and grain boundaries and very fine V-rich MC precipitates in the intragranular regions, which is very much similar to that prevailed in BM prior to FSW. Both the PWDT and PWNT treatments caused considerable reduction in the hardness of SZ. In the as-welded state, the 200 rpm joints have shown room temperature impact toughness close to that of BM, whereas 700 rpm joints exhibited very poor impact toughness. The best combination of microstructure and mechanical properties could be obtained by employing low rotational speed of 200 rpm followed by PWNT cycle. The type and size of various precipitates, grain size, and evolving dislocation substructure have been presented and comprehensively discussed.

Investigation on Micro structural and Mechanical Properties of Friction Stir Welded AZ91E Mg Alloy

Friction Stir Welding (FSW) is an eco-friendly solid state welding technique employed particularly for joining aluminium and magnesium alloys since they are difficult to join by conventional joining processes. The influence of tool rotational speed on mechanical properties of friction stir welded AZ91E magnesium alloy was investigated. The FSW processes were carried out at different rotational speeds of 900 rpm, 1000 rpm, 1100 rpm and 1200 rpm and at a constant axial load and transverse speed of 3 KN and 90 mm/min respectively. Further, the micro structural analysis and mechanical testing were performed on the welded joints. It inferred that the dynamic recrystallization have taken place in the friction stir welded zone as a result the joints fabricated at 1000 rpm rotational speed had an increase of 110% in Ultimate Tensile Strength compared to the base metal .

Influence of Tool Rotation Speed on Macrostructure, Microstructure and Mechanical behaviour of Dissimilar Friction Stir Welded AA2014-T6 and AA7075-T6 Aluminum Alloys

Material joining technologies lately investigates the prospects of utilizing dissimilar aluminum alloys in automotive and ship building ventures to diminish their manufacturing cost. Friction Stir Welding (FSW) technique is a potential answer for dissimilar metal joining than other customary joining techniques. This paper investigates the influence of tool rotational speed on joining dissimilar AA2014-T6 and AA7075-T6 aluminum alloys using FSW. The joints are made by altering the tool rotational speed within the range and by maintaining welding speed and shoulder diameter to pin diameter ratio at optimized values. An aggregate of five joints were manufactured to bring out the metallographic and mechanical behaviour of the joints. Microstructural assessment of the weld zone affirms the arrangement of recrystallized fine grain dissemination and proper material blending at the stir zone. The ultimate tensile strength and microhardness of the joints were assessed for the joints and presented. The outcomes confirmed that the joint made-up with 1300 rpm rotational speed displays a higher strength and better quality weld.

Influence of Tool Rotational Speed on the Mechanical Properties of Friction Stir Welded Al-Cu-Li Alloy

Aluminum-Lithium alloys have been found to exhibit superior mechanical properties as compared to the conventional aerospace aluminum alloys in terms of high strength, high modulus, low density, good corrosion resistance and fracture toughness at cryogenic temperatures. Even though they do not form low-melting eutectics during fusion welding, there are still problems like porosity, solidification cracking, and loss of lithium. This is why solid state friction stir welding is important in this alloy. It is known that using Al-Cu-Li alloy and friction stir welding to super lightweight external tank for space shuttle, significant weight reduction has been achieved. The objective of this paper is to investigate the effect of friction stir tool rotation speed on mechanical and microstructural properties of Al-Cu-Li alloy. The plates were joined with friction stir welding process using different tool rotation speeds (300-800 rpm) and welding speeds (120-420 mm/min), which are the two prime welding parameters in this process.

Microstructural and Mechanical Observations of Galvanized TRIP Steel after Friction Stir Spot Welding

Friction stir spot welding was done in transformation-induced plasticity steel sheets coated with zinc. The influence of tool rotational speed and dwell time on the microstructure and mechanical properties of lap-joints were investigated. After processing, different zones were formed in the joints. Microstructures in each zone depended on the welding conditions employed. Higher dwell time coupled with higher rotational speed promoted the deposition of a large amount of allotriomorphic ferrite beside the keyhole left by the pin. Coalesced bainite formation was stimulated by the deformation. Mechanical and chemical stabilization of the austenite occurred in different welding zones. Some zinc from the coating remained in the joint, in the stirring zone, representing a partial bonding between the steel sheets. The strength of the welds depended on a complex interaction between geometrical features, such as bonding ligament length and distance between the zinc and the keyhole left by the pin and the resultant microstructure in the stirring zone. The highest joint strength was observed for the “lowest tool rotational speed–highest dwell time” combination of welding parameters.