Studies of the characterization of weld joint created by using friction stir welding with stellite stir tool

Abstract A variety of tool shoulder designs comprising three families i.e. blade, spiral and circular shaped scrolls, were produced to improve the material flow and restrictions to avoid the tunnel void. The bobbin tools were manufactured by 3D printing additive manufacturing technology using solid filament. The butt weld joint was produced by each tool using plasticine as the workpiece material. The apparent surface features and bi-colour cross-sections provided a physical flow comparison among the shoulder designs. For the bobbin friction stir welding (BFSW), the tool shoulder with a three-spiral design produced the most stability with the best combination of the flow patterns on surface and cross-sections. The circular family tools showed a suitable intermixing on the surface pattern, while the blade scrolls showed better flow features within the cross-sections. The flow-driven effect of the shoulder features of the bobbin-tool design (inscribed grooves) was replicated by the 3D-printed tools and the analogue modelling of the weld samples. Similar flow patterns were achieved by dissimilar aluminium-copper weld, validating the accuracy of the analogue plasticine for the flow visualization of the bobbin friction stir welding.

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Characterization of Electrically Hybridized Friction Stir Welding of Mild Steel and Optimization of Process Parameters

Springer Proceedings in Materials - Next Generation Materials and Processing Technologies ◽

10.1007/978-981-16-0182-8_38 ◽

2021 ◽

pp. 505-517

Author(s):

Dilip Kumar Singh ◽

Kaushik Sengupta ◽

Arpan Kumar Mondal ◽

Debtanu Patra ◽

Arindam Dhar

Keyword(s):

Friction Stir Welding ◽

Mild Steel ◽

Process Parameters ◽

Friction Stir ◽

Optimization Of Process Parameters

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Mechanical and Corrosion Behavior of Pure Aluminium Added Friction Stir Weld Joint of Aluminium Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.821.327 ◽

2019 ◽

Vol 821 ◽

pp. 327-333

Author(s):

Sunil Sinhmar ◽

Dheerendra Kumar Dwivedi

Keyword(s):

Friction Stir Welding ◽

Aluminium Alloy ◽

Corrosion Behavior ◽

Weld Joint ◽

Second Phase ◽

Pure Aluminium ◽

Nugget Zone ◽

Friction Stir ◽

Aluminium Addition ◽

Aluminium Strip

Friction stir welding (FSW) of AA2014 aluminium alloy was performed by sandwiching pure aluminium (Al) in the form of strip between the abutting surfaces. Mechanical and corrosion behavior of weld joint with and without pure aluminium addition was compared. Friction stir welding was carried out at rotational speed of 931 rpm and traverse speed of 41 mm/min. Pure aluminium strip of 1 mm thickness was used for incorporating Al in weld nugget zone. Microstructure analysis was carried out using optical microscope and FESEM with energy dispersive spectroscopy (EDS). Microhardness and tensile testing were performed on the weld joints. Corrosion behavior was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) test. FESEM analysis was performed before and after corrosion test. Traces of pure aluminium strip were observed in the microstructure. The incorporated strip was found not to be uniformly distributed in the nugget zone. Pure aluminium addition reduced the extent of formation of the second phase particle in the nugget zone as compared to the normal FSW joint i.e. without Al addition. This metallurgical homogeneity resulted in better corrosion resistance of the Al added weld joint than the normal FSW joint.

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A Comparative Investigation on Conventional and Stationary Shoulder Friction Stir Welding of Al-7075 Butt-Lap Structure

Metals ◽

10.3390/met9121264 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1264 ◽

Cited By ~ 1

Author(s):

Yu Chen ◽

Huaying Li ◽

Xiaoyu Wang ◽

Hua Ding ◽

Fenghe Zhang

Keyword(s):

Friction Stir Welding ◽

Material Flow ◽

Comparative Investigation ◽

Flow Mode ◽

Nugget Zone ◽

Friction Stir ◽

Stationary Shoulder ◽

Average Grain Size ◽

Al 7075

Both conventional friction stir welding (C-FSW) and stationary shoulder friction stir welding (S-FSW) were employed to join the Al-7075 butt-lap structure, then the microstructural evolution and mechanical characterization of all FSW joints were systematically studied. The C-FSW joint exhibited a rough surface with flashes and arc corrugations, while the surface of the S-FSW joint became smooth. Moreover, for the S-FSW joint, the shoulder-affected zone got eliminated and the material flow mode during FSW was changed owning to the application of stationary shoulder. Furthermore, in comparison to C-FSW, the lower welding heat input of S-FSW decreased the average grain size in the nugget zone and inhibited the coarsening of strengthening precipitates in the heat-affected zone, elevating the overall hardness for the S-FSW joint. In addition, the tensile strength of the S-FSW joint became higher compared to the C-FSW joint, and all the FSW joints failed inside the nugget zone attributing to the existence of hook defect. The sharp-angled hook defect deteriorated the plasticity of the C-FSW joint further, which was only 70% that of the S-FSW joint.

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TEM Characterization of a 7042 Aluminum FSW Joint

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.186.331 ◽

2012 ◽

Vol 186 ◽

pp. 331-334

Author(s):

Mateusz Kopyściański ◽

Stanislaw Dymek ◽

Carter Hamilton

Keyword(s):

Plastic Deformation ◽

Aluminum Alloy ◽

Friction Stir Welding ◽

Dislocation Density ◽

Severe Plastic Deformation ◽

Base Material ◽

Friction Stir ◽

Tem Characterization ◽

Equiaxed Grains

This research characterizes the changes in microstructure that occur in friction stir welded extrusions of a novel 7042 aluminum alloy. Due to the presence of scandium the base material preserved the deformation microstructure with elongated grains and fairly high dislocation density. The temperature increase with simultaneous severe plastic deformation occurring during friction stir welding induced significant changes in the microstructure within the weld and its vicinity. The weld center (stir zone) was composed of fine equiaxed grains with residual dislocations and a modest density of small precipitates compared to the neighbouring thermomechanically and heat affected zones where the density of small precipitates was much higher.

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