Effects of pin thread on the in-process material flow behavior during friction stir welding: A computational fluid dynamics study

Chen, Gaoqiang; Li, Han; Wang, Guoqing; Guo, Zhixiong; Zhang, Shuai; Dai, Qi; Wang, Xibo; Zhang, Gong; Shi, Qingyu

doi:10.1016/j.ijmachtools.2017.09.002

Cited by 164 publications

(39 citation statements)

References 29 publications

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“…The frictional boundary condition proposed in [32,33] was applied in the presented study. The frictional stress at the interface may be represented as: [34]…”

Section: Numerical Simulationmentioning

confidence: 99%

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Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

et al. 2019

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The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

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“…The frictional boundary condition proposed in [32,33] was applied in the presented study. The frictional stress at the interface may be represented as: [34]…”

Section: Numerical Simulationmentioning

confidence: 99%

“…Flow stress of the workpiece was considered to be dependent on temperature and strain rate. It can be obtained by: [33]…”

Section: Numerical Simulationmentioning

confidence: 99%

Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

et al. 2019

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“…Ref. [32] used a moving mesh technique for finding the pin thread impact on the flow of the material. In the paper, the material which is located in the pin thread channels is considered as an extra fluid volume moving mesh and as a transient phenomenon, moving mesh approaches for the CFD-based FSW analysis were considered.…”

Section: Cfd Methodsmentioning

confidence: 99%

“…Furthermore, the stress calculations are only dependent on the velocity gradient, therefore in a large extent, the computational costs for the CFD models are less than CSM models [43]. Presented CFD-based FSW analysis permits the improvement of the spatial resolution, hence much complicated geometrical features can be simulated by CFD based models [32]. Whereas, the mean stress also called the forecast pressure has more ambiguity in the CFD based analyses, due to the negligence of elasticity [9].…”

Section: Computational Approachesmentioning

confidence: 99%

Progress in Thermomechanical Analysis of Friction Stir Welding

Meyghani

2020

Chin. J. Mech. Eng.

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This article reviews the status of thermomechanical analysis of the friction stir welding (FSW) process for establishing guidelines for further investigation, filling the available research gaps, and expanding FSW applications. Firstly, the advantages and applications of FSW process are introduced, and the significance and key issues for thermomechanical analysis in FSW are pointed out. Then, solid mechanic and fluid dynamic methods in modeling FSW process are described, and the key issues in modeling FSW are discussed. Different available mesh modeling techniques including the applications, benefits and shortcomings are explained. After that, at different subsections, the thermomechanical analysis in FSW of aluminum alloys and steels are examined and summarized in depth. Finally, the conclusions and summary are presented in order to investigate the lack of knowledge and the possibilities for future study of each method and each material.

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“…Some studies have reported either shoulder profile [11][12][13] or pin design [14][15][16][17][18][19][20] effect on the mechanical properties of FSWed joints. Flat shoulder profile with conical pin is the simplest design and has been used successfully for joining aluminum alloys [21,22]. Also, adding a step to a conical pin [23] and half screwed pin (in comparison to full screwed) [24] was shown to increase the joint mechanical properties and to eliminate the cavity defect.…”

Section: Introductionmentioning

confidence: 99%

Effect of tool geometry and welding speed on mechanical properties of dissimilar AA2198–AA2024 FSWed joint

Khalilabad

Zedan

Texier

et al. 2018

Journal of Manufacturing Processes

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Keywords:Friction stir welding FSW tool design Al-Li alloys Welding speed 2024 aluminum alloy Tensile properties DIC A B S T R A C T Different tool geometries were used to investigate the joining of aluminum alloys (AA2198 to AA2024) by friction stir welding (FSW). Three shoulder profiles (flat, raised spiral, and raised fan) and five different pin profiles (cone, half threaded cylindrical, straight cylindrical, tapered cylindrical and square) were selected. Preliminary investigations were conducted by moving the tool into a seamless sheet made of the AA2024-T3 in order to select the tools that produce defect-free joints. Preliminary investigations showed the raised fan shoulder profile helps the material flow from the edge of shoulder to the pin creating a smooth surface finish with no flash in comparison with flat and raised spiral shoulder profiles. Pins with a minimum diameter equal to half the plate thickness produced lack of penetration (LOP) defects, while increasing minimum pin diameter to the plate thickness eliminates the LOP defects. Half threaded cylindrical pin produced tunneling defect, whereas defect free joint made by straight cylindrical, tapered cylindrical and cubic pin profiles. So they were selected for joining AA2024 to AA2198. Fracture locations of different joint variants were observed the vicinity of the thermomechanical affected zone (TMAZ) of AA2198-T3 alloy, and in the nugget on the AA2198-T3 side which have the minimum hardness and highest strain localization as confirmed by hardness maps and digital image coronation (DIC). Higher measured temperature than dissolution temperature of AA2198 main strengthening precipitates could be the reason of low hardness and fracture in TMAZ and center of nugget. Furthermore a raised fan shoulder with a tapered cylindrical pin produced highest elongation and yield strength and it was selected as the best candidate for optimization of the welding parameters. It was found that higher rotational and traverse speeds enhance the formation of tunneling and kissing bond defects, suggesting that longer pins have to be used for higher traverse speeds. Welding speed 750 rpm with 450 mm min −1 could create joint with highest yield strength.

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Effects of pin thread on the in-process material flow behavior during friction stir welding: A computational fluid dynamics study

Cited by 164 publications

References 29 publications

Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Progress in Thermomechanical Analysis of Friction Stir Welding

Effect of tool geometry and welding speed on mechanical properties of dissimilar AA2198–AA2024 FSWed joint

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