TWI Digital Library

An economic analysis was undertaken to compare the costs of onshore and offshore pipeline construction scenarios for welds made using friction stir welding (FSW) and conventional mechanised MIG/MAG welding. Pipe diameters of 1067 and 305 mm were sel…

Models to predict the precipitate and grain size evolution in AA7449 aluminium alloy friction stir welds are presented and compared with experimental data. Bead on plate welds on 3.2 mm thickness sheets of composition Al, 8.4%Zn, 2.1%Mg, 1.8%Cu were…

With regard to the occurrence of residual oxide defects associated with friction stir welding (FSW) of aluminium alloys, an investigation is presented into a possible alternative mechanism for oxide formation within the weld nugget involving enhance…

Friction stir welding (FSW) was employed to fabricate a single overlap joint between sheet specimens (thickness 1.5 mm) of an AA 6181-T4 aluminium alloy and ZStE-340 high-strength steel, and weld phase composition, microstructure and mechanical prop…

The deformation behaviour and microstructural evolution of friction stir processed Zn, 22%Al rolled sheet (thickness 3 mm) were compared with those of the corresponding superplastic alloy. Friction stir processing was performed at a rotational speed…

Following a description of the swept FSW spot welding process, experimental work on welding conditions is presented. A design of experiments (DOE) approach was employed to examine the effect of process parameters on unguided lap shear tensile streng…

With regard to the occurrence of coarse alpha-Al dendrites, eutectic phase, shrinkage porosity and other defects in cast aluminium alloys, an investigation was undertaken into the influence of different combinations of friction stir processing (FSP)…

With regard to the development of friction stir shaping as a modified friction stir welding (FSW) process to maximise material flow within the weld zone and redistribute it into new shapes or features outside of or on top of the weld zone, an invest…

In order to study the relationship between material flow and the development of highly variant process forces during friction stir welding (FSW), a high sampling rate triaxial force measurement device and a high speed camera were employed to monitor…

6061-T6 aluminium alloy (Al, 0.96%Mg, 0.59%Si) sheets (thickness 1 mm) were joined by friction stir spot welding (FSSW) under low rotational speed conditions and the microstructure and mechanical properties of the welded joints were investigated. FS…

Lap joints were fabricated in AA 7075-T6 aluminium alloy sheets (thickness 2 mm) using an ESAB "Rosio" friction stir welding (FSW) robot and the effect tool of side-tilt angle on welded joint tensile strength was investigated. A "CounterStir" FSW to…

An investigation is presented into the development of the stationary shoulder self-reacting pin tool (SSSRPT) as a friction stir welding variant and the application of the tool to fabrication of butt joints in sheets (thickness 4 mm) of A6N01 alloys…

The results of a programme to establish self reacting friction stir welding for thin gauge (less than 3 mm) aluminium alloy applications are reported divided into the five major phases: tool development; joint evaluation; strength optimisation; prot…

Modelling tools were developed to describe the relationships between process parameters, microstructural evolution and mechanical properties of the weld in friction stir welding (FSW). Experiments were conducted using aluminium alloy 6056. Initial t…

Work from two projects is described: "Qualistir" for the on-line quality control of friction stir welding in aluminium (by ultrasonic phased array examination of butt welded Al 7075); and a TWI feasibility study on inspection of Al 5083 butt and lap…

Computational fluid dynamics (CFD) methods were used to model the metal flow in the friction stir welding (FSW) process in order to optimise the pin profile to minimise the traversing force; welding experiments were carried out to validate the findi…

The influences of the thermal and mechanical stresses experienced during friction stir welding on the structure of coarse-grained aluminium alloy 2519-T87 were investigated. Plate of 25 mm thickness was welded at a speed of 1.5 mm/s, using a tool sp…

Friction stir welding (FSW) was investigated in aluminium alloys used in aircraft structures. Extruded shapes in alloys 2024 (Al, 4.96%Cu), 7475 (Al, 5.96%Zn, 2.57%Mg, 1.62%Cu) and 7050 (Al, 6.29%Zn, 2.36%Mg, 2.00%Cu) were welded; welds were evaluat…

A procedure has been developed for repairing welds made by friction stir welding (FSW) in cases where the tool breaks during welding. It involves the following stages: excavating the broken FSW tool, milling out a slot across the hole, machining an …

The quality of friction stir welds of butt joints (including the use of inserts to simulate compensation for poor fit up) between aluminium alloys 5083-H12 (Al, 4.6%Mg, 0.6%Mn, 0.3%Si) and 6082-T6 (Al, 0.7%Mg, 0.9%Si, 0.5%Mn), was evaluated. The wel…