Torque, power requirement and stir zone geometry in friction stir welding through modeling and experiments

Friction stir welding (FSW) of high strength materials is challenging due to high tool cost and low tool life. To address this issue, the present investigation deals with an alternative of plasma-assisted friction stir welding (PFSW) of DH36 steel with WC-10%Co tool. Plasma preheating current (13 A, 15 A, and 17 A) was varied by keeping other FSW parameters as constant. During the FSW and PFSW process, force measurement and thermal history aided in a deep understanding of the process, tool degradation mechanisms, accompanied by the mechanical and microstructural characterization of the welded joints. The stir zone hardness was increased from 140 HV0.5 to about 267 HV0.5. The yield and tensile strength of weld increased from 385 MPa and 514 MPa to about 391 MPa and 539 MPa, respectively. Weld joint elongation (%) was increased from ~10% of weld 1 to ~13.89% of weld 4. During PFSW, the process temperature was increased, the cooling rate was lowered, and the weld bead was widened. The results also revealed that the plasma-assisted weld resulted in polygonal ([Formula: see text]) and allotriomorphic ferrite as the major constituents in the stir zone. Pearlite dissolution and spheroidization were observed in the ICHAZ and SCHAZ, respectively. Additionally, the plasma preheating reduced the tungsten tool’s wear by 58% compared to FSW.

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Stir zone material flow patterns during friction stir welding of heavy gauge AA5056 workpieces and stability of its mechanical properties

Metal Working and Material Science ◽

10.17212/1994-6309-2021-23.4-140-154 ◽

2021 ◽

Vol 23 (4) ◽

pp. 140-154

Author(s):

Tatiana Kalashnikova ◽

◽

Vladimir Beloborodov ◽

Kseniya Osipovich ◽

Andrey Vorontsov ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Friction Stir Welding ◽

Elevated Temperatures ◽

Thin Sheet ◽

Stir Zone ◽

Clear Correlation ◽

Material Structure ◽

Friction Stir ◽

Significant Difference

Introduction. Friction stir welding and processing are almost identical processes of severe plastic deformation at elevated temperatures. These technologies differ mainly in the purpose of its use: the formation of a hardened surface layer or producing a welded joint. However, it is known that both during welding and during processing of heavy gauge workpieces temperature gradients occur. As a result, the conditions of adhesive interaction, material plastic flow, and the formation of the stir zone change as compared to thin-sheet workpieces with fundamentally different heat dissipation rates. In this connection, the purpose of the work is to determine the regularities of the structure formation and stability of the mechanical properties in different directions in the material of 35-mm-thick aluminum-magnesium alloy samples produced by friction stir welding/processing. Research Methodology. The technique and modes of friction stir welding and processing of AA5056 alloy workpieces with a thickness of 35 mm are described. Data on the equipment used for mechanical tests and structural research are given. Results and discussion. The data obtained show the excess mechanical properties of the processing zone material over the base metal ones in all studied directions. Material structure heterogeneities after friction stir welding/processing of heavy gauge workpieces have no determining effect on the stir zone properties. At the same time, there is no clear correlation between the tensile strength values and the load application direction, nor is there any significant difference in mechanical properties depending on the location of the samples inside the stir zone. The average ultimate tensile strength values in the vertical, transverse, and longitudinal directions are 302, 295 and 303 MPa, respectively, with the yield strength values of 155, 153 and 152 MPa, and the relative elongation of 27.2, 27.5, 28.7 %.

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Research on the Friction Stir Welding of Sc-Modified AA2519 Extrusion

Metals ◽

10.3390/met9101024 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1024 ◽

Cited By ~ 5

Author(s):

Robert Kosturek ◽

Lucjan Śnieżek ◽

Janusz Torzewski ◽

Marcin Wachowski

Keyword(s):

Mechanical Properties ◽

Friction Stir Welding ◽

Base Material ◽

Stir Zone ◽

Welding Parameters ◽

Friction Stir ◽

Treated Condition ◽

Heat Treated ◽

Heat Treated Condition ◽

Fsw Parameters

The aim of this research was to investigate the effect of friction stir welding (FSW) parameters on microstructure and mechanical properties of Sc-modified AA2519 extrusion joints. The workpiece was welded by FSW in non-heat-treated condition with seven different sets of welding parameters. For each obtained joint macrostructure and microstructure observations were performed. Mechanical properties of joints were investigated using tensile test together with localization of fracture location. Joint efficiencies were established by comparing measured joints tensile strength to the value for base material. The obtained results show that investigated FSW joints of Sc-modified AA2519 in the non-heat-treated condition have joint efficiency within the range 87–95%. In the joints obtained with the lowest ratio of the tool rotation speed to the tool traverse speed, the occurrence of imperfections (voids) localized in the stir zone was reported. Three selected samples were subjected to further investigations consisting microhardness distribution and scanning electron microscopy fractography analysis. As the result of dynamic recrystallization, the microhardness of the base material value of 86 HV0.1 increased to about 110–125 HV0.1 in the stir zone depending on the used welding parameters. Due to lack of the strengthening phase and low strain hardening of used alloy the lack of a significantly softened zone was reported by both microhardness analysis and investigation of the fractured samples.

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Friction-Stir Welding of Zr-Modified AA5083 Sheets in Different Conditions

Materials Science Forum ◽

10.4028/www.scientific.net/msf.877.365 ◽

2016 ◽

Vol 877 ◽

pp. 365-370

Author(s):

Sergey Malopheyev ◽

Sergey Mironov ◽

Rustam Kaibyshev

Keyword(s):

Friction Stir Welding ◽

Post Weld Heat Treatment ◽

Stir Zone ◽

Friction Stir ◽

Ultrafine Grained ◽

Aa5083 Aluminum Alloy ◽

Cold Rolled ◽

Material Conditions ◽

Hot Rolled ◽

Zone Microstructure

The effect of friction-stir welding (FSW) on microstructure and mechanical properties of Zr-modified AA5083 aluminum alloy was studied. FSW was observed to lead to the formation of fully recrystallized ultrafine-grained microstructures and preservation of nanoscale dispersoids in stir zone. The joint efficiency of the friction-stir welds for ultimate tensile strength was found to be 94% and 74% in the hot-rolled and cold-rolled preprocessed material conditions. The stir zone microstructure was predicted to be stable against abnormal grain growth during post-weld heat treatment.

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Estimation of Material Flow in Stir Zone during Friction Stir Welding by Distribution Measurement of Si Particles

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.47.224 ◽

2006 ◽

Vol 47 (1) ◽

pp. 224-232 ◽

Cited By ~ 33

Author(s):

Hidetoshi Fujii ◽

Young Gon Kim ◽

Takuya Tsumura ◽

Toru Komazaki ◽

Kazuhiro Nakata

Keyword(s):

Friction Stir Welding ◽

Material Flow ◽

Stir Zone ◽

Distribution Measurement ◽

Friction Stir

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Friction Stir Welding of Aluminum Metal Matrix Composite Containers for Electric Components

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.611-612.1445 ◽

2014 ◽

Vol 611-612 ◽

pp. 1445-1451 ◽

Cited By ~ 4

Author(s):

Jukka Pakkanen ◽

Andreas Huetter ◽

Cecilia Poletti ◽

Norbert Enzinger ◽

Christof Sommitsch ◽

...

Keyword(s):

Thermal Expansion ◽

Friction Stir Welding ◽

Metal Matrix Composite ◽

Matrix Composite ◽

Metal Matrix ◽

Base Material ◽

Stir Zone ◽

Friction Stir ◽

Joint Geometry ◽

Gas Tightness

For aerospace applications, light-weight boxes to protect and carry electronic equipment need to be sealed. The main requirements on the components are low thermal expansion and gas tightness. The common material for such an application is a metal matrix composite (MMC). The MMC suggested here consists of A356 aluminum alloy matrix with 15 vol.% SiC particle reinforcement. A safe limit for the electronic component inside the boxes during sealing is determined to be 180°C. Due to the boundary conditions gas tightness and low heat input, Friction Stir Welding (FSW) might be an alternative to the employed joining techniques. For the FSW process the T-Joint is the most appropriate joint geometry in respect to the box design. The geometry of the lid has to ensure the backing system for the stir zone inside the box. A successful welding of the box was done after a joint geometry optimization. The examination of the welded box concerns material characterization with microscopic methods, measuring thermal expansion in base material and stir zone and temperature measurement while FSW.

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Investigation of Microstructure and Mechanical Properties of Friction Stir Lap Jointed Ni Base Superalloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.724.481 ◽

2012 ◽

Vol 724 ◽

pp. 481-485

Author(s):

Kuk Hyun Song ◽

Kazuhiro Nakata

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Friction Stir Welding ◽

Base Material ◽

Lap Joints ◽

Stir Zone ◽

Inconel 600 ◽

Friction Stir ◽

Microstructure And Mechanical Properties ◽

Average Grain Size

This study evaluated the microstructure and mechanical properties of friction stir welded lap joints. Inconel 600 and SS 400 as experimental materials were selected, and friction stir welding was carried out at tool rotation speed of 200 rpm and welding speed of 100 mm/min. Applying the friction stir welding was notably effective to reduce the grain size of the stir zone, as a result, the average grain size of Inconel 600 was reduced from 20 μm in the base material to 8.5 μm in the stir zone. Joint interface between Inconel 600 and SS 400 showed a sound weld without voids and cracks. Also, the hook, along the Inconel 600 alloy from SS 400, was formed at advancing side, which directly affected an increase in peel strength. In this study, we systematically discussed the evolution on microstructure and mechanical properties of friction stir lap jointed Inconel 600 and SS 400.

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Effect of welding parameters on mechanical properties and microstructure of friction stir welded brass joints

Matériaux & Techniques ◽

10.1051/mattech/2018060 ◽

2018 ◽

Vol 106 (6) ◽

pp. 606 ◽

Cited By ~ 1

Author(s):

İnan Geçmen ◽

Zarif Çatalgöl ◽

Mustafa Kemal Bilici

Keyword(s):

Mechanical Properties ◽

Friction Stir Welding ◽

Rotation Speed ◽

Stir Zone ◽

Weld Strength ◽

Welding Parameters ◽

Feed Speed ◽

Friction Stir ◽

Tool Rotation Speed ◽

Tool Rotation

Friction stir welding is a method developed for the welding of high-alloy aluminum materials which are difficult to combine with conventional welding methods. Friction stir welding of MS 63 (brass) plates used different tools (tapered cylindrical, tapered threaded cylindrical), tool rotational speeds (1040, 1500, 2080 rpm) and traverse speeds (30,45,75,113 mm.min−1). Tensile, bending, radiography and microstructure tests were carried out to determine the mechanical properties of brass plates joined by friction stir welding technique. Microstructure characterization studies were based on optical microscope and SEM analysis techniques. In addition, after joining operations, radiographs were taken to see the internal structure failure. Brass sheets were successfully joined to the forehead in the macrostructure study. In the evaluation of the microstructure, it was determined that there were four regions of base metal, thermomechanically affected zone (TMEB), heat-affected zone (HAZ) and stir zone. In both welding tools, the weld strength increased with increasing tool rotation speed. The particles in the stir zone are reduced by increasing of the tool rotation speed. Given the strength and % elongation values, the highest weld strength was achieved with tapered pin tool with a tool rotation speed of 1040 rpm and a tool feed speed of 113 min−1.

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Effect of Shoulder Diameter on the Resulting Interfacial Regions of Friction Stir Welds between Aluminium and Copper

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.299-300.1146 ◽

2011 ◽

Vol 299-300 ◽

pp. 1146-1150

Author(s):

Esther Titilayo Akinlabi ◽

Stephen Akinlabi

Keyword(s):

Friction Stir Welding ◽

Feed Rate ◽

Rotational Speed ◽

Force Feedback ◽

Welding Process ◽

Microstructural Characterization ◽

Stir Zone ◽

Vertical Force ◽

Friction Stir ◽

Shoulder Diameter

This paper reports the effect of shoulder diameter on the resulting interfacial regions of joints between aluminium and copper produced by the friction stir welding process. The welds were produced using three shoulder diameter tools, viz; 15, 18 and 25 mm. This paper focuses on welds produced at a constant rotational speed of 600 rpm and feed rate of 50 mm/min varying the shoulder diameters. Analysis of the force feedback revealed that the advancing force, the downward vertical force and the torque increases as the shoulder diameter increases. Microstructural characterization was conducted on the joint interfaces and it was observed that the widths of the interfacial regions comprising of the Stir Zone and the Thermo – Mechanically Affected Zone (TMAZ) increases as the shoulder size increases.

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