scholarly journals Mechanical, electrochemical and structural characteristics of friction stir spot welds of aluminium alloy 6063

2020 ◽  
Vol 7 ◽  
pp. 25
Author(s):  
Delphine Mulaba-Kapinga ◽  
Kasongo Didier Nyembwe ◽  
Omolayo Michael Ikumapayi ◽  
Esther Titilayo Akinlabi
Keyword(s):  
Shear Strength ◽  
Rotational Speed ◽  
Dwell Time ◽  
Structural Characteristics ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Spot Welds ◽  
Corrosion Properties ◽  
Influence Of Process Parameters ◽  
Friction Stir

The work presents the friction stir spot welding (FSSW) of AA6063. The evolving properties due to the influence of process parameters and the efficacy of metallurgical, structural, mechanical, and electrochemical integrities were studied. FSSW was conducted on 2mm thickness by varying the rotational speed of 600, 900 and 1200 rpm and the dwell time at 10 and 15 s. The evolving microstructures, hardness, corrosion, shear tensile behaviours and X-ray diffraction characteristics of the as-received material and the welds were studied. As the tool rotational speed increased at a constant dwell time, a smooth and debris free spot welds were noticed, more HAZ formations became visible and more intermetallic phases of aluminium magnesium (AlMg) were formed although with very low peaks during structural assessment. Furthermore, the hardness values increased up to a certain limit and then decreased, the corrosion properties in artificial seawater (ASW) shown significant improvement on the spot-welded samples and the tensile shear strength was also improved. It would be recommended that spot welds at 900 rpm and 10 and/or 15 s for applications where the hardness is significant imperative and at 1200 rpm with 10 and/or 15 s dwell time where higher tensile shear strength is required and lastly, 1200 rpm at 15 s where corrosion application is significant.

Effects of Process Parameters on Tensile Shear Strength of Friction Stir Spot Welded Aluminium Alloy (EN AW 5005)

2014 ◽  
Vol 59 (1) ◽  
pp. 221-224 ◽  
Author(s):  
M.K. Kulekci
Keyword(s):  
Shear Strength ◽  
Aluminium Alloy ◽  
Process Parameters ◽  
Dwell Time ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Friction Stir ◽  
Tool Pin ◽  
Tool Rotation ◽  
Spot Welded

Abstract Aluminium and its alloys have been used in automotive technology since the first model of the car. The need for aluminium material is getting increased for weight reduction, improved fuel economy and vehicle performance. The amount of the aluminium used in a car is mainly related with joining processes of aluminium alloy. This can be achieved by developing the welding techniques for aluminium alloys. The purpose of this study was to determine the effects of friction stir spot welding parameters on tensile shear strength of friction stir spot welded lap joint EN AW 5005 Aluminium alloy. The variable parameters were tool rotation (rpm), dwell time (s) and the tool pin height (mm). Tensile shear test results indicated that the weld performance was significantly affected by the tool rotation, dwell time and the tool pin height. The results of the study indicates that there are optimum process parameters which give the highest tensile shear strength.

Effects of process time and thread on tensile shear strength of Al alloy lap joint produced by friction stir spot welding

2010 ◽  
Vol 24 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Mitsuo Fujimoto ◽  
Daisuke Watanabe ◽  
Natsumi Abe ◽  
Sato S. Yutaka ◽  
Hiroyuki Kokawa
Keyword(s):  
Shear Strength ◽  
Spot Welding ◽  
Friction Stir Spot Welding ◽  
Process Time ◽  
Al Alloy ◽  
Tensile Shear Strength ◽  
Lap Joint ◽  
Tensile Shear ◽  
Friction Stir

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.

The investigation into vibration effect on microstructure and mechanical characteristics of friction stir spot vibration welded aluminum: Simulation and experiment

2020 ◽  
Vol 234 (9) ◽  
pp. 1809-1822 ◽  
Author(s):  
Behrouz Bagheri ◽  
Mahmoud Abbasi ◽  
Reza Hamzeloo
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Shear Strength ◽  
Finite Element Simulation ◽  
Stir Zone ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Friction Stir ◽  
Element Simulation ◽  
Workpiece Vibration

In this study, an innovative technique is employed to modify the microstructure and increase the mechanical characteristics of the Al5083 joint made by friction stir spot welding (FSSW). In this technique entitled FSSVW (friction stir spot vibration welding), the workpiece is vibrated during FSSW. Noted processes were modeled and finite element simulation results were also analyzed. The results showed that workpiece vibration during FSSW led to grain refinement, larger weld region, and improvement of the mechanical properties, namely tensile shear strength and hardness, of the joint. Stir zone grain size decreased by about 25% and tensile shear strength value increased by about 20% by applying workpiece vibration during FSSW. The results also indicated that the tensile shear strength and hardness enhanced, as vibration frequency increased. It was concluded that the presence of vibration increased the material deformation in the stir zone and led to enhanced deformation of the material. This intensified the dynamic recrystallization and resulted in grain refinement. It was also found that tensile residual stresses developed in the stir zone of FSS and FSSV welded specimens and tensile residual stress values for FSSV welded specimens were higher than those for FSS welded specimens for about 10%. It was concluded that the effect of grain size on hardness is higher than the effect of residual stress. Higher ductility is predicted for FSSV welded specimen with higher vibration frequency and also for specimen welded with less dwell time; finite element simulation was also applied to analyze the effects of workpiece vibration during FSSW on strain distribution as well as hardness and residual stress distribution within the joint during FSSW and FSSVW processes. Finite element simulation results had good compatibility with experimental results. It was concluded that the strain values and flow velocity relating to the FSSVW process are higher than those relating to the FSSW process.

scholarly journals An approach to improving the mechanical properties of friction stir spot welded joints on the basis of hook formation mechanism

2020 ◽  
Vol 01 ◽  
Author(s):  
Shuaishuai Du ◽  
Huijie Liu ◽  
Yanying Hu ◽  
Tengfei Yang
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Formation Mechanism ◽  
Material Flow ◽  
Low Pressure ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Friction Stir ◽  
Pressure Zone ◽  
Hook Geometry

Background: Partial metallurgical bond (namely 'hook') is formed between the overlapped metal sheets during friction stir spot welding (FSSW). The geometry of hook is found to significantly affect the mechanical performance of FSSWed joints, while that how to adjust hook geometry to a better state remains to be studied. Methods: The conventional FSSW joints under different plunge depths and dwelling time were obtained. The cross-sectional morphology of each spot weld was investigated to clarify the material flow behavior and deduce the formation mechanism of hook. The tensile shear strength and fracture features were examined to reveal the effect of hook geometry on the mechanical properties. Results: The weld geometry affects the tensile shear strength of FSSWed joints by determining their fracture modes. The formation mechanism of hook is deduced by a material flow model. In the tool-plunging stage, the faying interface is broken by upward-flowing materials, hook is therefore initiated and driven up gradually. During the tool-dwelling stage, hook continues to migrate to the low-pressure zone, surrounding the stir zone. Conclusion: The uncertainty of crack-propagating endpoint along hook makes it difficult to ensure the mechanical properties of welds. If the hook endpoint has not yet reached the low-pressure zone at the end of welding process, welds with ideal hook geometry can be obtained. Target friction stir spot welds were produced by the use of a tool possessing smaller pin diameter.

Friction Stir Lap Joining of Blanks under Different Conditions

2015 ◽  
Vol 651-653 ◽  
pp. 1433-1438 ◽  
Author(s):  
Carlo Bruni ◽  
Alessio D'Orazio ◽  
Mohamad El Mehtedi
Keyword(s):  
Numerical Simulation ◽  
Shear Strength ◽  
Numerical Simulations ◽  
Welded Joints ◽  
Rotational Velocity ◽  
Tool Geometry ◽  
Tensile Shear Strength ◽  
Trial And Error ◽  
Tensile Shear ◽  
Friction Stir

The present investigation aims at studying the effect of the tool geometry and of rotational velocity of the tool, at different welding velocities, on the tensile shear strength of the friction stir welded joints realised with blanks of different thicknesses. The proposed trial and error methodology was based on experiments, numerical simulations and microstructure observations.It was observed that, at the lowest rotational velocity, the slender tool determines tensile shear strength values lower than those obtained with the thick tool in particular at the highest welding velocity investigated. The numerical simulation evidenced a wider stirred zone for the thick tool when compared with that realised with the slender tool at the lowest rotational velocity. Microstructure observations evidenced that the increase in the welding velocity determines reduced stirred zones and an homogenisation of material particularly relevant for the slender tool.

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