In the case of annealed materials, tensile tests usually fail in the unaffected material well away from the weld and heat affected zone. The weld properties of fully hardened cold worked or heat treated aluminium alloys can be improved by controlling the thermal cycle, in particular by reducing the annealing and overageing effects in the thermomechanically affected zone, where the lowest hardness and strength are found after welding.
For optimum properties it would seem that, for the latter, a heat treatment after welding is the best choice, although it is recognised that this will not be a practical solution for many applications. Mechanical properties of friction stir welded Al specimens Material 0. Friction stir welded aluminium panels in the shipbuilding industry The first commercial application of FSW concerned the manufacture of hollow aluminium panels for deep freezing of fish on fishing boats Figure 8.
These panels are made from friction stir welded aluminium extrusions at Sapa [19]. The minimal distortion and high reproducibility make FSW both technically and economically a very attractive method to produce these stiff panels.
Sapa FSW aluminium panel for pressing of fish blocks before quick freezing. The panel is welded from both sides [19]. Large aluminium ship panel made from H aluminium alloy extrusions, made by Sumitomo Light Metal [20]. Friction stir welded aluminium tanks and boosters for spacecraft An increasing number of fuel tanks for spacecraft are now being produced from difficult-to-weld aluminium alloys.
Friction stir welding procedures for welding end domes into cylindrical high-quality tanks have been developed for cryogenic oxygen storage vessels. It has been proposed to shrink fit an aluminium backing ring into the tank before the last circumferential weld is made. The joint is then simultaneously made between three members: the end dome, the cylindrical shell and the backing ring. The latter may remain in the tank after welding.
Potential for using friction stir welded aluminium panels in the aircraft production The FSW process offers tremendous potential for low-cost fastenerless joining of lightweight aluminium airframe structures. EADS sees a high potential for joining aluminium alloys by FSW for skin-to-skin fuselage connections of their future Airbus production.
They presented data recently that demonstrates that the mechanical and technological properties of these welds seem to approach almost the properties of the parent material [25].
Friction stir welded hollow aluminium panels in the rolling stock industry Hollow profiles and T-stiffener extrusions are used and are currently being friction stir welded in the railway industry for the manufacture of commuter and high-speed trains.
They installed an Esab SuperStir TM machine, which has two welding heads to weld hollow extrusions from both sides simultaneously Figure The machine has a carousel-type loading and unloading station and is automatically loaded by an articulated arm robot. The FSW machine is at the same site as the extrusion press, and therefore the surface quality and tolerances of the extrusions are extremely good prior to welding. The automotive components have very tight tolerances, which would be difficult to achieve with conventional fusion welding processes.
Now they are produced by FSW with less than 60sec cycle time, and Sapa reported that their customer was very pleased with the weld quality. Sapa developed a quality management system based on computerised statistical control of all major dimensions of the welded workpieces, and this leads to virtually no parts being rejected or re-machined.
The station for measuring the dimensions of the welded component is located directly behind the FSW cell and loaded and supervised by the operator of the FSW cell. The measured actual data is fed back into the welding machine for parameter adjustment. Sapa's Esab-SuperStir TM machine with two welding heads for welding hollow aluminium extrusions simultaneously from both sides. Hydro Aluminium's light alloy car wheel, where the rim was friction stir welded to the hub [32].
These machines are representing the state of the art of commercially available FSW equipment and will be used in the EuroStir TM Project [36] which is part funded by the Eureka programme and focuses on 'European Industrialisation of Friction Stir Welding'. The first contract was signed between Esab and TWI. The equipment has a gantry type design with a welding area of 8 x 5m and two heads of different sizes. The first head will be used for welding thin sheets with high rotation speeds.
The second head can be used for thick sheets while applying high downward forces. The machine will be capable of welding aluminium alloys with more than 15mm thickness over the full working envelope. Up to 25mm thick aluminium plates can be welded in the centre line of the machine. It is expected that the first machine will be delivered to TWI in April and will then be used initially for test welding and laboratory operations.
At a later stage the machine will be used for welding full size industrial prototypes. The machine is large enough to weld for example a complete side panel of a double-decker bus. It can react up to 10t force. Conclusions Friction stir welding is being exploited in the shipbuilding, automotive and rolling stock industry sectors to produce aluminium panels from and series extrusions.
The aerospace industry applies the process successfully for the manufacture of spacecraft made from high-strength aluminium alloys. The experiments with Whorl TM and Triflute TM tools have to date produced promising results and proved that the FSW process can be applied for joining up to 75mm thick aluminium plates.
FSW can also be used for copper, lead, magnesium, zinc and titanium alloys, as well as for steel and stainless steel. Shibaura Institute of Technology, Japan.
Thomas W M: 'Friction stir welding of ferrous materials; a feasibility study'. Lohwasser D: 'Application of friction stir welding for aircraft industry'. Velocci A L Jr: 'Eclipse presses ahead amid wide scepticism'.
Dawes C J: 'Friction stir welding aluminium ships'. Midling O T: 'Friction stir welding - a valuable processing route'. Aluminium '97 Conf, Sept , Essen, Germany. This triggered ardent investigations and researches on the friction joining.
A machine tool research group brought back useful information from the USSR. Designed, manufactured and started marketing specialized manufacturing equipment.
It was renamed later as the Society for the Study of Friction Joining and further to the Friction Joining Association, which continues activities to this day. New factory built in Obu City.
All equipment from Shinkawa and Atsuta factories moved there. In cooperation with Toyota Motor Corporation, Izumi developed and started marketing the innovative Center Broach mechanical broaching machine. The No. Accelerating innovation. Why Choose Friction Welding. The significant difference between inertia friction welding and direct drive welding is that inertia friction welding requires much higher rotational speeds to achieve a welding bond.
Inertia friction welding is commonly found in friction welding that involves thermoplastics, but not always. It is very commonly used with lightweight metals in the aerospace industry as well.
Regardless of their differences, both types of friction welding operate on the same basic principle—using the heat generated by frictional resistance at high speeds to fuse metals. There are many benefits of friction welding that make it a popular form of welding in automated factory assemblies.
Here are some of the pros associated with friction welding:. As you can see, there are multiple benefits to using friction welding in the manufacturing process, most of which result in a more durable weld overall. For certain kinds of joints, friction welding offers several advantages. Along with the benefits that friction welding offers, there are also some disadvantages associated with this type of welding, too.
Here are some of the drawbacks of friction welding:. Overall, friction welding is very effective, but only useful in a few scenarios.
However, friction welding is used across many industries for metalworking and assembly. These are some of the things that are welded with friction welding:. Friction welding is especially prevalent in aerospace and marine manufacturing , where it is used to create safe, solid joints without sacrificing aerodynamics or increasing the weight of the assembly through the addition of fillers.
Friction welding is also used in nuclear engineering applications. In these industries, frictional welding is often used as a way to ensure quick, strong bonds between dissimilar metals. Inertia friction welding is friction welding that is accomplished via a series of flywheels that use a motor and a spindle shaft to bring the welding joint up to high levels of rotational speed and heat before disengaging.
This process heats and plasticizes the surfaces of the two joined pieces through the force of inertia friction, causing a full-strength bond to be formed once the pieces are allowed to stop and cool.
Rotary friction welding is the oldest type of friction welding and was invented in the s. Friction welding was pioneered by Japanese engineers in the mids for use in automotive brake manufacturing by Toyota , but soon after, it spread like wildfire across the global metalworking community. Some of the advantages of using friction welding are:.
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