Study of friction stir spot welding for thermotolerant engineering thermoplastic polyimide joints

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.

2017 ◽  
Vol 867 ◽  
pp. 105-111
Author(s):  
S. Ramesh Babu ◽  
M. Nithin ◽  
S. Pavithran ◽  
B Parameshwaran

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.


Author(s):  
N Farmanbar ◽  
SM Mousavizade ◽  
M Elsa ◽  
HR Ezatpour

In the present work, AA5052 sheets with thickness of 1 mm were successfully welded by protrusion friction stir spot welding as a low cost single-step method with a simple design that produces the no-keyhole joints with special mechanical properties at short dwell time and low tool rotation speed. By using suitable process parameters, the process is able to produce welds with superior mechanical performance in items of peak load and energy absorption compared to other techniques. The plunging depth and dwell time in this method were set as 0.2 mm and 6 s, respectively. The tool rotation speed was changed as 500, 800, 1250, and 1600 r/min to determine the optimum condition based on the microstructural and mechanical properties. Welds strength produced by the protrusion friction stir spot welding was directly related to the joint thickness, and the effective thickness of the upper sheet was maximum at 500 r/min. Protrusion friction stir spot welding joints presented circumferential failure mode after tensile shear testing. Regarding the sheets thickness used in this study, the joints produced by the current work presented high load bearing ability at dwell time of 6 s and tool rotation speed of 500 r/min compared to other techniques.


2021 ◽  
Author(s):  
Aydin Jadidi ◽  
Reza Bagherian Azhiri ◽  
Amir Baghdadchi ◽  
Abolfazl Salmani Bideskan

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%.


2020 ◽  
Vol 899 ◽  
pp. 117-125
Author(s):  
Armansyah ◽  
Juri Saedon ◽  
Hwi Chie Ho ◽  
Shahriman Adenan

In an initiative to reveal the property of welded joint, investigation and assessment of the welding parameters in friction stir spot welding (FSSW) was carried out. In this study, the AA5052-H112 sheets with 2mm thickness was welded using cylindrical tool pin profile under different combinations of main process parameters i.e. spindle speed, tool depth, and dwell time. The fatigue test under cyclical load condition was performed to investigate the dynamic behavior of the welded joint. Failure mode analysis on the fracture of the weld joint after fatigue test was took also consideration. Finally, results from the test were evaluated using analysis of variance (ANOVA) to deter-mine statistically significant factors and associated percentage contribution together with the generation of main effects plots. From ANOVA results, dwell time had the highest influence on fatigue load with a PCR of 52.8%, followed by the spindle speed 37.1%, and then tool depth 6%.


2014 ◽  
Vol 493 ◽  
pp. 739-742 ◽  
Author(s):  
Ario Sunar Baskoro ◽  
Suwarsono ◽  
Gandjar Kiswanto ◽  
Winarto

Technology of Friction Stir Welding (FSW) is a relatively new technique for joining metal. In some cases on Aluminum joining, FSW gives better results compared with the arc welding processes, including the quality of welds and less distortion. The purpose of this study is to analyze the parameters effect of high speed tool rotation onmicro Friction Stir Spot Welding(μFSSW) to theshear strengthof welds. In this case, Aluminum material A1100, with thickness of 0.4 mm was used. Tool material of HSS material was shaped with micro grinding process. The spindle speed was fixed at 30000 rpm. Tool shoulder diameter was 3 mm, and a length of pin was 0.7 mm. The parameter variations used in this study were the variable of pin diameter (1.5 mm, 2.0 mm, and 2.5 mm), a variable ofplunge speed(2 mm/min, 4 mm/min, 6 mm/min), and the variable ofdwell time(2 seconds, 4 seconds, 6 seconds). Where the variation of these parameters will affect to the mechanical properties of welds (as response) was theshear strength.Response Surface Methods(RSM) was used to analyze μFSSW parameters with theshear strengthof welds. From the result of experiment and analysis, it is shown that the important welding parameters in high speed μFSSW process are pin diameter and plunge speed.


2010 ◽  
Vol 24 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Mitsuo Fujimoto ◽  
Daisuke Watanabe ◽  
Natsumi Abe ◽  
Sato S. Yutaka ◽  
Hiroyuki Kokawa

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