scholarly journals Parameters optimization for friction spot welding of AZ31 magnesium alloy by Taguchi method

2012 ◽  
Vol 17 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Leonardo Contri Campanelli ◽  
Uceu Fuad Hasan Suhuddin ◽  
Jorge Fernandez dos Santos ◽  
Nelson Guedes de Alcântara
Keyword(s):  
Shear Strength ◽  
Magnesium Alloy ◽  
Rotational Speed ◽  
Spot Welding ◽  
Dwell Time ◽  
Az31 Magnesium Alloy ◽  
Lap Shear Strength ◽  
Plunge Depth ◽  
Friction Spot Welding ◽  
Lap Shear

Friction spot welding (FSpW) is a solid state welding process suitable for producing spot-like joints, especially in lightweight materials, which are particularly interesting due to the weight saving potential. The plunging of an especially designed non-consumable and rotating tool creates a connection between overlapped sheets through frictional heat and plastic deformation. Minimum material loss is observed, and therefore a fully consolidated joint with flat surface (no keyhole) is obtained. In the current study, the effect of FSpW parameters, such as rotational speed, plunge depth and dwell time, on lap shear strength of AZ31 magnesium alloy joints was investigated. The optimization of input process parameters was carried out through Taguchi approach of DOE. Analysis of variance was applied to determine the individual importance of each parameter. Main effect plots were used to indicate the best levels for maximizing lap shear strength. The results show that tool plunge depth has the higher effect on the weld strength, followed by rotational speed and dwell time.

Friction Stir Spot Welding of AZ31B Magnesium Alloy

2017 ◽  
Vol 867 ◽  
pp. 105-111
Author(s):  
S. Ramesh Babu ◽  
M. Nithin ◽  
S. Pavithran ◽  
B Parameshwaran
Keyword(s):  
Shear Strength ◽  
Magnesium Alloy ◽  
Rotational Speed ◽  
Spot Welding ◽  
Dwell Time ◽  
Friction Stir Spot Welding ◽  
Resistance Welding ◽  
Hardness Distribution ◽  
Tool Rotational Speed ◽  
Friction Stir

The Electrical Resistance Welding (ERW) of Magnesium and Aluminium is more difficult than steel because the welding machines must provide high currents and exact pressures in order to provide the heat necessary to melt the magnesium for proper fusion at the interface in order to produce a sound weld. Further, resistance welding of magnesium requires a backup plate made of steel to conduct the heat to the workpiece material. To overcome this problem, Friction Stir Spot Welding (FSSW) has been developed. In this study, the hardness distribution and the tensile shear strength of FSSW welds in the AZ31B Magnesium alloy has been investigated and it has been found that tool rotational speed and dwell time plays a major role in determining the weld strength. From the experimental study, a tool rotational speed of 1100 rpm and dwell time of 20 s produced good shear strength of 2824 N and the corresponding grain size was 4.54 μm. This result is very well supported by microstructural examinations and hardness distribution studies.

Preliminary Investigation on Friction Spot Welding of AZ31 Magnesium Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 3016-3021 ◽  
Author(s):  
L.C. Campanelli ◽  
U.F.H. Suhuddin ◽  
Jorge Fernandez Dos Santos ◽  
N.G. Alcantara
Keyword(s):  
Magnesium Alloy ◽  
Spot Welding ◽  
Welding Process ◽  
High Energy ◽  
Az31 Magnesium Alloy ◽  
Frictional Heat ◽  
Welding Parameters ◽  
Friction Stir ◽  
Friction Spot Welding ◽  
Lap Shear

Friction spot welding (FSpW) is a recent solid state welding process developed and patented by GKSS Forschungszentrum (now Helmholtz-Zentrum Geesthacht), Germany. A spot-like connection is produced by means of an especially designed non-consumable tool consisting of pin, sleeve and clamping ring that creates a joint between sheets in overlap configuration through frictional heat and plastic deformation. FSpW offers many advantages over conventional spot joining techniques including high energy efficiency, surface quality and environmental compatibility. Comparing with friction stir spot welding, FSpW produces a weld without keyhole on the surface at the end of the joining process. In the present study, the possibility of joining AZ31 magnesium alloy by FSpW technique was evaluated by using different welding parameters (rotational speed, plunge depth and dwell time), aiming to produce high quality connections. Microstructural features were analyzed by light optical microscope and mechanical performance was investigated by microhardness test and lap shear test. Microstructure analysis revealed that defects free welds could be produced. A slight decrease in grain size of the stir zone was observed causing a slight increase in the microhardness of this region. The preliminary lap shear data demonstrated that the weld strength is comparable to other welding process.

scholarly journals Simultaneous Effect of Tool Rotation and Dwell Time on Quality of Dissimilar AA5052-Copper Joints Fabricated by Friction Stir Spot Welding

2021 ◽  
Author(s):  
Aydin Jadidi ◽  
Reza Bagherian Azhiri ◽  
Amir Baghdadchi ◽  
Abolfazl Salmani Bideskan
Keyword(s):  
Shear Strength ◽  
Spot Welding ◽  
Dwell Time ◽  
Quality Characteristics ◽  
Friction Stir Spot Welding ◽  
Lap Joints ◽  
Lap Shear Strength ◽  
Friction Stir ◽  
Lap Shear ◽  
Rotary Speed

Abstract In the present study, lap joints of dissimilar 5052 aluminum alloy and pure copper were fabricated by friction stir spot welding process. The work was aimed to find effect of parameters such as tool rotary speed (1000, 1400 and 2000 RPM) and dwell time (5, 10 and 15s) on microstructure and strength properties of lap joints. Also, statistical models of the quality characteristics were developed to understand which interaction has dominant effect on quality characteristics. Research findings showed that to obtain sound joints with high lap shear strength tool rotary speed of 2000 rpm and dwell time of 5s should be selected. It provides sufficient heat input and prevents the excessive material softening. On the other hand, to achieve maximum hardness, 2000 rpm tool rotary speed should be chosen to provide enough heat for formation of intermetallic compound and 10s dwell time should be used prevent enough time for microstructure refining. Moreover, from the statistical analyses, it was found that dwell time and tool speed are the significant factor for lap shear strength and hardness, respectively. In order to attain simultaneous maximum strength and hardness, tool speed of 2000 rpm and dwell time of 8 s should be used. In such condition lap shear strength of 1755 N and hardness of 77 V are achieved with desirability of 85%.

scholarly journals Ultrasonic spot welding of lightweight alloys

2021 ◽  
Author(s):  
Vikas Patel
Keyword(s):  
Shear Strength ◽  
Spot Welding ◽  
Intermetallic Layer ◽  
Zinc Coating ◽  
Micro Hardness ◽  
Simultaneous Application ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Structural Applications ◽  
Welding Processes

Automotive and aerospace sectors have a pressing need for structural components that are lighter and stronger, aiming to improve energy efficiencies and reduce anthropogenic environment. Steel has already a wide variety of structural applications in the transportation industry due to its excellent properties. To further reduce CO2 emissions, lightweight magnesium (Mg) and aluminum (Al) alloys have increasingly been used in the vehicle fabrication due to their lower density, higher specific strength and stiffness, excellent size stability and process ability. The structural application of these alloys inevitably involves welding and joining of similar Mg-to-Mg and Al-to-Al, and dissimilar Mg-to-Al, Mg-to-steel and Al-to-steel. Resistance spot welding produces coarse grains, large defects and thick brittle intermetallic compounds (IMCs) in the weld metal. Alternative solid-state welding processes are being considered such as ultrasonic spot welding (USW), which produces coalescence through the simultaneous application of localized high-frequency vibratory energy and moderate clamping forces. In this study, USW was successfully carried out on similar Mg alloy and dissimilar Mg-to-Al, Mg-to-steel and Al-to-steel alloys. The overall objective of this work is to gain a better understanding of the dominant factors determining the joint performance, with particular emphasis on the microstructural evolution, crystallographic texture, micro-hardness, lap shear strength, fatigue resistance, fatigue life prediction model and fracture analysis of similar and dissimilar USWed joints. Overall, USWed Mg-to-Mg is stronger and more consistent in terms of weldability than the dissimilar USWed Mg-to-Al, Mg-to-steel and Al-to-steel. This was attributed to the large volume of thick brittle IMCs and significantly higher welds center hardness in dissimilar metals welding, which is the main cause of joint failure. The IMCs were confirmed by XRD, EDS and micro-hardness measurement tests.. Therefore, another objective of this study is to minimize the presence of brittle IMCs and engineer an acceptable intermetallic layer to produce sound joints between Mg-to-Al, Mg-to-steel and Al-to-steel. A third material (tin foil or zinc coating) was placed in-between the work pieces. With this procedure, the lap shear strength of the welded samples was increased. The detailed microstructural characterization and mechanical properties of welded joints with an interlayer are presented.

scholarly journals Microstructure and mechanical properties of an ultrasonic spot welded aluminum alloy: the effect of welding energy

2021 ◽  
Author(s):  
He Peng ◽  
Daolun Chen ◽  
Xianquan Jiang
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
Cyclic Loading ◽  
Crack Growth ◽  
Failure Mode ◽  
Spot Welding ◽  
Energy Levels ◽  
Lap Shear Strength ◽  
Pull Out ◽  
Lap Shear

The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique–ultrasonic spot welding (USW)–at different energy levels. An ultra-fine necklace-like equiaxed grain structure is observed along the weld line due to the occurrence of dynamic crystallization, with smaller grain sizes at lower levels of welding energy. The tensile lap shear strength, failure energy, and critical stress intensity of the welded joints first increase, reach their maximum values, and then decrease with increasing welding energy. The tensile lap shear failure mode changes from interfacial fracture at lower energy levels, to nugget pull-out at intermediate optimal energy levels, and to transverse through-thickness (TTT) crack growth at higher energy levels. The fatigue life is longer for the joints welded at an energy of 1400 J than 2000 J at higher cyclic loading levels. The fatigue failure mode changes from nugget pull-out to TTT crack growth with decreasing cyclic loading for the joints welded at 1400 J, while TTT crack growth mode remains at all cyclic loading levels for the joints welded at 2000 J. Fatigue crack basically initiates from the nugget edge, and propagates with “river-flow” patterns and characteristic fatigue striations. Keywords: aluminum alloy; ultrasonic spot welding; EBSD; microstructure; tensile strength; fatigue

scholarly journals Ultrasonic spot welding of lightweight alloys

2021 ◽  
Author(s):  
Vikas Patel
Keyword(s):  
Shear Strength ◽  
Spot Welding ◽  
Intermetallic Layer ◽  
Zinc Coating ◽  
Micro Hardness ◽  
Simultaneous Application ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Structural Applications ◽  
Welding Processes

Automotive and aerospace sectors have a pressing need for structural components that are lighter and stronger, aiming to improve energy efficiencies and reduce anthropogenic environment. Steel has already a wide variety of structural applications in the transportation industry due to its excellent properties. To further reduce CO2 emissions, lightweight magnesium (Mg) and aluminum (Al) alloys have increasingly been used in the vehicle fabrication due to their lower density, higher specific strength and stiffness, excellent size stability and process ability. The structural application of these alloys inevitably involves welding and joining of similar Mg-to-Mg and Al-to-Al, and dissimilar Mg-to-Al, Mg-to-steel and Al-to-steel. Resistance spot welding produces coarse grains, large defects and thick brittle intermetallic compounds (IMCs) in the weld metal. Alternative solid-state welding processes are being considered such as ultrasonic spot welding (USW), which produces coalescence through the simultaneous application of localized high-frequency vibratory energy and moderate clamping forces. In this study, USW was successfully carried out on similar Mg alloy and dissimilar Mg-to-Al, Mg-to-steel and Al-to-steel alloys. The overall objective of this work is to gain a better understanding of the dominant factors determining the joint performance, with particular emphasis on the microstructural evolution, crystallographic texture, micro-hardness, lap shear strength, fatigue resistance, fatigue life prediction model and fracture analysis of similar and dissimilar USWed joints. Overall, USWed Mg-to-Mg is stronger and more consistent in terms of weldability than the dissimilar USWed Mg-to-Al, Mg-to-steel and Al-to-steel. This was attributed to the large volume of thick brittle IMCs and significantly higher welds center hardness in dissimilar metals welding, which is the main cause of joint failure. The IMCs were confirmed by XRD, EDS and micro-hardness measurement tests.. Therefore, another objective of this study is to minimize the presence of brittle IMCs and engineer an acceptable intermetallic layer to produce sound joints between Mg-to-Al, Mg-to-steel and Al-to-steel. A third material (tin foil or zinc coating) was placed in-between the work pieces. With this procedure, the lap shear strength of the welded samples was increased. The detailed microstructural characterization and mechanical properties of welded joints with an interlayer are presented.

Evaluating weld properties of conventional and swept friction stir spot welded 6061-T6 aluminium alloy

2019 ◽  
Vol 9 (8) ◽  
pp. 851-860 ◽  
Author(s):  
S. Suresh ◽  
K. Venkatesan ◽  
Elango Natarajan ◽  
S. Rajesh ◽  
Wei Hong Lim
Keyword(s):  
Shear Strength ◽  
Aluminium Alloy ◽  
Rotational Speed ◽  
Shear Fracture ◽  
Shear Loading ◽  
Tool Rotational Speed ◽  
Lap Shear Strength ◽  
Friction Stir ◽  
Lap Shear ◽  
Weld Properties

6061-T6 aluminium alloy is a tempered grade aluminium material that is extensively used, particularly in space and automotive applications. The conventional and swept friction stir spot welding (FSSW) joints are prepared by varying tool rotational speed at four different levels. The mechanical properties, microstructure and mode of failure in both types of FSSW are evaluated and reported. The high plastic deformation and fine grains influenced the increase in hardness of the weld joints based on the Hall-Petch equation. The highest lap shear strength of 5.31 kN is observed in swept FSSW sample prepared at 1400 rpm. Interestingly, 1600 rpm decreased the lap shear strength due to insufficient friction between base metal and tool in the higher tool rotational speed. The minimum microhardness is noticed in heat-affected zone (HAZ) of both cases. Conventional FSSW samples showed shear fracture, nugget pullout fracture and circumferential fracture under lap shear loading, whereas swept FSSW showed only the circumferential fracture.

Surface Treatment to Promote Joining of Glass Fiber Reinforced Plastic and AZ31 Magnesium Alloy for Fiber Metal Laminates via Hot Metal Pressing

2021 ◽  
Vol 883 ◽  
pp. 111-118
Author(s):  
Lucia Lizzul ◽  
Marco Sorgato ◽  
Andrea Ghiotti ◽  
Stefania Bruschi
Keyword(s):  
Shear Strength ◽  
Magnesium Alloy ◽  
Glass Fiber ◽  
Metal Composite ◽  
Fiber Reinforced ◽  
Fiber Metal Laminates ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Glass Fiber Reinforced ◽  
Fiber Metal

When fabricating fiber metal laminates, the joining between the metal sheet and the composite is affected by the chemical and mechanical properties at the interface. To this end, this study investigated the influence of different induced-surface characteristics of AZ31B magnesium alloy sheets when joint with glass fiber reinforced polyamide 6. The treatments, carried out to modify the AZ31B surfaces, were annealing, sandblasting, and their combination. The mechanical and chemical interlocking at the metal-composite interface was assessed in terms of macroscopic and microscopic defects as well as lap shear strength. The obtained results indicated that the joint effectiveness was mainly affected by the annealing treatment, which induced both a chemical and morphological modification of the surface. The formed oxide layer at the interface, combined with surface topography modification, were capable to increase the lap shear strength up to 87%.

Sign in / Sign up

Export Citation Format

Share Document