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
Author(s):  
Morteza Asadollahi ◽  
Neda Jabbari ◽  
Soheil Nakhodchi ◽  
Hossein Salimi ◽  
Hamed Haddad Khodaparast

The tensile-shear strength of AA 5052 single and multi-friction stir spot welding joints were analyzed using experimental, numerical, and analytical approaches. Benchmark specimens were designed and manufactured in a similar manner with respect to industrial practice. Under the fixed welding process condition, the failure mechanism of friction stir spot welded specimens under tensile-shear loading was first determined by using macro- and micro-structural analysis. It is shown that increasing the tool shoulder diameter and the number of friction stir spot weldings may nonproportionally increase the strength of the joints. In the linearly arranged multi-friction stir spot welding joints, the strength of these joints was discussed using analytical approach. It is demonstrated that in certain cases, increasing the nugget diameter is preferred than increasing the number of nuggets. This is only applicable to a certain friction stir spot welding failure mechanism. A finite element model prediction tool was developed to predict the tensile-shear strength of friction stir spot welded joints using the material properties obtained from the measurement of experimental hardness.


2012 ◽  
Vol 579 ◽  
pp. 109-117 ◽  
Author(s):  
Yuan Ching Lin ◽  
Ju Jen Liu ◽  
Ben Yuan Lin

The effects of tool geometry on the microstructure and tensile shear strength of friction stir spot-welded A6061-T6 Al alloy sheets were investigated in the present study. Friction stir spot welding (FSSW) was carried out at a tool speed of 2500 rpm, plunging rate of 1 mm/s, and dwell time of 3 s. Four types of tools with the same shoulder shape and size, but different pin profiles (threaded cylindrical, smooth cylindrical, threaded triangular, and smooth triangular) were used to carry out FSSW. The mechanical and metallurgical properties of the FSSW specimens were characterized to evaluate the performance of the different tools. Experimental results show that the pin profile significantly alters the hook geometry, which in turn affects the tensile shear strength of the friction stir spot welds. The welds made using the conventional thread cylindrical tool have the largest elongation and yield the highest tensile strength (4.78 kN). The welds made using the smooth cylindrical tool have the lowest tensile strength. The welds made using the threaded triangular and smooth triangular tools both have a tensile-shear load of about 4 KN; however, the welds made using the threaded triangular tool have a better elongation than those made using the smooth triangular tool.


2018 ◽  
Vol 786 ◽  
pp. 104-118
Author(s):  
M.H. Fahmy ◽  
Hamed Abdel-Aleem ◽  
M.R. Elkousy ◽  
N. M. Abdel-Elraheem

This investigation is performed to compare the resistance spot welding (RSW) of aluminum alloy (2024-T3) with friction stir spot welding (FSSW) techniques. In this work, parameters of both resistance spot welding (RSW) and friction stir spot welding (FSSW) techniques were optimized and the optimum welding variables for both techniques were obtained. For FSSW, the tensile shear strength increased with increasing probe length, tool rotational speed and tool holding time. Tensile shear force value of RSW is about 66% of that of FSSW. This is explained by the coarse dendritic structure in resistance spot welding compared to the plastically deformed stir zone and heat affected zone in FSSW. The ratio of nugget shear strength of RSW and FSSW to base metal is about 71% and 149% respectively. The maximum hardness was obtained in stir zone at the surface of the tool. Very fine grain size of about 4 microns was obtained in stir zone followed by elongated and rotated grains in TMAZ where dynamic recrystallization did not occur.


Author(s):  
Jicheng Gao ◽  
Jiachen Dong ◽  
Sunyi Zhang ◽  
Liang Yu ◽  
Huiming Jin ◽  
...  

In this research, thermoplastic polyimide (TPI) were welding via friction stir spot welding (FSSW) in order to evaluate the feasibility of the technology. The welding tool with a tri-flute pin was used for keeping the welding effectiveness. The effect of the rotation speed and dwell time on the microstructure and shear strength was studied. The results shows that the number of gap defects between the shoulder affect zone and the pin affect zone decreased with the increase of the rotation speed. The boundary of the shoulder affect zone and the pin affect zone was no clear when increasing the dwell time from 10 s to 20 s. Long dwell time could increase the mixing time and reduce the materials viscosity, which made the structure was denser. The maximal shear strength was obtained 85.5% of the base materials. The differential scanning calorimetry (DSC) results indicated that the melting behaviour of different regions was no obvious difference. It indicated that FSSW had a feasible and potential technology to join the high temperature resistant engineering plastics.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Thongchai Arunchai ◽  
Kawin Sonthipermpoon ◽  
Phisut Apichayakul ◽  
Kreangsak Tamee

Resistance Spot Welding (RSW) is processed by using aluminum alloy used in the automotive industry. The difficulty of RSW parameter setting leads to inconsistent quality between welds. The important RSW parameters are the welding current, electrode force, and welding time. An additional RSW parameter, that is, the electrical resistance of the aluminum alloy, which varies depending on the thickness of the material, is considered to be a necessary parameter. The parameters applied to the RSW process, with aluminum alloy, are sensitive to exact measurement. Parameter prediction by the use of an artificial neural network (ANN) as a tool in finding the parameter optimization was investigated. The ANN was designed and tested for predictive weld quality by using the input and output data in parameters and tensile shear strength of the aluminum alloy, respectively. The results of the tensile shear strength testing and the estimated parameter optimization are applied to the RSW process. The achieved results of the tensile shear strength output were mean squared error (MSE) and accuracy equal to 0.054 and 95%, respectively. This indicates that that the application of the ANN in welding machine control is highly successful in setting the welding parameters.


2013 ◽  
Vol 795 ◽  
pp. 492-495 ◽  
Author(s):  
Mohd Noor Mazlee ◽  
Alvin Tan Yin Zhen ◽  
Shamsul Baharin Jamaludin ◽  
Nur Farhana Hayazi ◽  
Shaiful Rizam Shamsudin

Tensile shear strength and ageing treatment of dissimilar 6063 aluminum alloy-316L stainless steel joint fabricated by spot welding were investigated. The results showed that tensile shear strength increased with the increasing of welding current. The enhancement of tensile shear strength of the joints was due to the enlargement of the nugget diameter. It was also found that the tensile shear strength values for heat treated joint almost similar to that of non-heat treated joint.


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