AA5052 sheets welded by protrusion friction stir spot welding: High mechanical performance with considering sheets thickness at low dwelling time and tool rotation speed
Abstract: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 ti… Show more
“…The presence of keyhole is a barrier to achieve high strength welds in FSSW process. 138 To avoid this keyhole defect refill FSSW method proposed by Helmholtz. 139 were it is used to fill the key hole left behind the tool with special tool.…”
In this century, innovation and technology are required to fabricate the hybrid joint of metal and polymers. Due to their lightweight and anti-corrosion properties, the mixed components are increasingly used to produce lightweight hybrid structures such as aerospace and automobiles. It is essential to develop welding techniques for joining dissimilar materials and instead use them in engineering structures. The bonding mechanism of the weld joint has varied depending upon the welding process. In the present review, the bonding mechanism of various hybrid joints like Friction stir welding (FSW), Friction stir spot joining, Friction riveting, laser welding, ultrasonic welding and induction welding is discussed in detail. The defects observed in the different welding process is discussed in details. The mechanical properties and microstructure analysis of different hybrid joints are reviewed in detail for a different combination of hybrid joints.
“…The presence of keyhole is a barrier to achieve high strength welds in FSSW process. 138 To avoid this keyhole defect refill FSSW method proposed by Helmholtz. 139 were it is used to fill the key hole left behind the tool with special tool.…”
In this century, innovation and technology are required to fabricate the hybrid joint of metal and polymers. Due to their lightweight and anti-corrosion properties, the mixed components are increasingly used to produce lightweight hybrid structures such as aerospace and automobiles. It is essential to develop welding techniques for joining dissimilar materials and instead use them in engineering structures. The bonding mechanism of the weld joint has varied depending upon the welding process. In the present review, the bonding mechanism of various hybrid joints like Friction stir welding (FSW), Friction stir spot joining, Friction riveting, laser welding, ultrasonic welding and induction welding is discussed in detail. The defects observed in the different welding process is discussed in details. The mechanical properties and microstructure analysis of different hybrid joints are reviewed in detail for a different combination of hybrid joints.
“…Such kind of fracture modes was observed in joints welded with lower levels of tool SD or PD as they influenced the material flow in PFSSW. 44,45 Figure 12.Shear fracture.…”
Friction stir spot welding, a solid-state metal joining process has been utilised to join dissimilar aluminium alloys using pinless tools. The optimal welding conditions were predicted using the Multi-start algorithm with 25 starting points and were validated by confirmation tests. The Multi-start algorithm predicted the maximum tensile shear force of 6.28 kN at the tool rotational speed of 841.83 r/min, plunge depth of 0.618 mm, shoulder diameter of 24.99 mm, plunging speed of 0.04 mm/s and dwell time of 8 s. The scanning electron microscopy analysis revealed the formation of flatter hooks in the weld zone. The electron backscatter diffraction scans revealed a decrease in grain size at the lower sheet (Al 5754) due to the action of 30 kN axial force during pinless friction stir spot welding. Two different modes of fracture were observed: (i) nugget pull-out with necking; (ii) shearing. The fracture modes were observed to be dependent on the process parameters like shoulder diameter and plunge depth.
“…Many new tools are coming up to join the steel material. Aato et al [1] used a tool without a tip to join steel in a lap position 0.5 mm thickness with a 3.6 mm diameter tool, and the joint showed failure at 1.8 kN by rotating the tool at 18000 rpm. There was no significant plastic flow near the welding surface which indicated It was due to the heat of the friction and Friction force pressure via a mechanism Close to distributed welding.…”
AA6062 and ST1020 materials are used to perform friction stir spot welding (FSSW). In this experiment, the mechanical and microstructural characteristics of the welded joint were determined using a square-head tip tool. To enhance the life of the welded joint, three essential process parameters, namely tool speed, dwell time, and plunge depth were employed with four levels. The L16 orthogonal array was adapted for experimental work to develop a process parameter table. A tensile test was performed for a larger better value to predict the strength of the welded joint, and the value is 5.65 kN. The outcome shows that dwell time is a more prominent parameter than tool speed and plunge depth. The optimal combination of welding parameters is a dwell time of 24 s, a tool rotational speed of 1200 rpm, and a plunge depth of 0.8 mm; dwell time contributes 39.66%, followed by a plunge depth 35.7%, and at last, tool speed 6.171%. Furthermore, to determine the optimum level of parameters. The microstructure of this joint was observed with respect to heat dissipation and changes in grain size. Microstructure studies were carried out to see the area under stir zone for workpieces with high and low tensile strength. This work was validated using the response surface method (RSM). The RSM results are very close to the experimental results.
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