Friction stir welding - AbsoluteAstronomy.com

Friction-stir welding (FSW) is a solid-state joining process (meaning the metal is not melted during the process) and is used for applications where the original metal characteristics must remain unchanged as far as possible. This process is primarily used on aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

, and most often on large pieces which cannot be easily heat treated post weld to recover temper characteristics.

It was invented and experimentally proven at The Welding Institute

The Welding Institute

The Welding Institute or TWI is a research and technology organisation with a specialty in welding. The Welding Institute is based in Cambridgeshire, England, since 1946, and has several offices around the world....

UK in December 1991. TWI holds a number of patents on the process, the first being the most descriptive.

Principle of operation

As experimentally proven by Wayne Thomas and his team at The Welding Institute, a constantly rotated cylindrical-shouldered tool with a profiled nib is traversely fed at a constant rate into a butt joint between two clamped pieces of butted material.
The nib is slightly shorter than the weld depth required, with the tool shoulder riding atop the work surface.

Friction

Friction

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...

al heat is generated between the wear-resistant welding

Welding

Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

components and the work pieces. This heat, along with that generated by the mechanical mixing process and the adiabatic heat within the material, cause the stirred materials to soften without melting

Melting point

The melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...

. As the pin is moved forward a special profile on its leading face forces plasticised material to the rear where clamping force assists in a forged consolidation the weld.

This process of the tool traversing along the weld line in a plasticised tubular shaft of metal results in severe solid state deformation involving dynamic recrystallization of the base material.

Microstructural features

The solid-state nature of the FSW process, combined with its unusual tool and asymmetric nature, results in a highly characteristic microstructure

Microstructure

Microstructure is defined as the structure of a prepared surface or thin foil of material as revealed by a microscope above 25× magnification...

. The microstructure can be broken up into the following zones:

The stir zone (also nugget, dynamically recrystallised zone) is a region of heavily deformed material that roughly corresponds to the location of the pin during welding. The grains within the stir zone are roughly equiaxed and often an order of magnitude smaller than the grains in the parent material. A unique feature of the stir zone is the common occurrence of several concentric rings which has been referred to as an "onion-ring" structure. The precise origin of these rings has not been firmly established, although variations in particle number density, grain size and texture have all been suggested.
The flow arm zone is on the upper surface of the weld and consists of material that is dragged by the shoulder from the retreating side of the weld, around the rear of the tool, and deposited on the advancing side.
The thermo-mechanically affected zone (TMAZ) occurs on either side of the stir zone. In this region the strain and temperature are lower and the effect of welding on the microstructure is correspondingly smaller. Unlike the stir zone the microstructure is recognizably that of the parent material, albeit significantly deformed and rotated. Although the term TMAZ technically refers to the entire deformed region it is often used to describe any region not already covered by the terms stir zone and flow arm.
The heat-affected zone
Heat-affected zone
The heat-affected zone is the area of base material, either a metal or a thermoplastic, which has had its microstructure and properties altered by welding or heat intensive cutting operations. The heat from the welding process and subsequent re-cooling causes this change in the area surrounding...

(HAZ) is common to all welding processes. As indicated by the name, this region is subjected to a thermal cycle but is not deformed during welding. The temperatures are lower than those in the TMAZ but may still have a significant effect if the microstructure is thermally unstable. In fact, in age-hardened aluminium alloys this region commonly exhibits the poorest mechanical properties.

Advantages and limitations

The solid-state nature of FSW immediately leads to several advantages over fusion welding methods since any problems associated with cooling from the liquid phase are immediately avoided. Issues such as porosity

Porosity

Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%...

, solute

Solution

In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

redistribution, solidification cracking and liquation cracking are not an issue during FSW. In general, FSW has been found to produce a low concentration of defects and is very tolerant to variations in parameters and materials.

Nevertheless, FSW is associated with a number of unique defects. Insufficient weld temperatures, due to low rotational speeds or high traverse speeds, for example, mean that the weld material is unable to accommodate the extensive deformation during welding. This may result in long, tunnel-like defects running along the weld which may occur on the surface or subsurface. Low temperatures may also limit the forging action of the tool and so reduce the continuity of the bond between the material from each side of the weld. The light contact between the material has given rise to the name "kissing-bond". This defect is particularly worrying since it is very difficult to detect using nondestructive methods such as X-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

or ultrasonic testing. If the pin is not long enough or the tool rises out of the plate then the interface at the bottom of the weld may not be disrupted and forged by the tool, resulting in a lack-of-penetration defect. This is essentially a notch in the material which can be a potent source of fatigue cracks.

A number of potential advantages of FSW over conventional fusion-welding processes have been identified:

Good mechanical properties in the as welded condition
Improved safety due to the absence of toxic fumes or the spatter of molten material.
No consumables — A threaded pin made of conventional tool steel
Tool steel
Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures...

, e.g., hardened H13, can weld over 1000m of aluminium, and no filler or gas shield is required for aluminium.
Easily automated on simple milling machines — lower setup costs and less training.
Can operate in all positions (horizontal, vertical, etc.), as there is no weld pool.
Generally good weld appearance and minimal thickness under/over-matching, thus reducing the need for expensive machining after welding.
Low environmental impact.

However, some disadvantages of the process have been identified:

Exit hole left when tool is withdrawn.
Large down forces required with heavy-duty clamping necessary to hold the plates together.
Less flexible than manual and arc processes (difficulties with thickness variations and non-linear welds).
Often slower traverse rate than some fusion welding techniques, although this may be offset if fewer welding passes are required.

Tool rotation and traverse speeds

There are two tool speeds to be considered in friction-stir welding; how fast the tool rotates and how quickly it traverses the interface. These two parameters have considerable importance and must be chosen with care to ensure a successful and efficient welding cycle. The relationship between the welding speeds and the heat input during welding is complex but, in general, it can be said that increasing the rotation speed or decreasing the traverse speed will result in a hotter weld. In order to produce a successful weld it is necessary that the material surrounding the tool is hot enough to enable the extensive plastic flow required and minimise the forces acting on the tool. If the material is too cold then voids or other flaws may be present in the stir zone and in extreme cases the tool may break.

Excessively high heat input, on the other hand may be detrimental to the final properties of the weld. Theoretically, this could even result in defects due to the liquation of low-melting-point phases (similar to liquation cracking in fusion welds). These competing demands lead onto the concept of a "processing window": the range of processing parameters viz. tool rotation and traverse speed, that will produce a good quality weld. Within this window the resulting weld will have a sufficiently high heat input to ensure adequate material plasticity but not so high that the weld properties are excessively deteriorated.

Tool tilt and plunge depth

The plunge depth is defined as the depth of the lowest point of the shoulder below the surface of the welded plate and has been found to be a critical parameter for ensuring weld quality. Plunging the shoulder below the plate surface increases the pressure below the tool and helps ensure adequate forging of the material at the rear of the tool. Tilting the tool by 2-4 degrees, such that the rear of the tool is lower than the front, has been found to assist this forging process. The plunge depth needs to be correctly set, both to ensure the necessary downward pressure is achieved and to ensure that the tool fully penetrates the weld. Given the high loads required the welding machine may deflect and so reduce the plunge depth compared to the nominal setting, which may result in flaws in the weld. On the other hand an excessive plunge depth may result in the pin rubbing on the backing plate surface or a significant undermatch of the weld thickness compared to the base material. Variable load welders have been developed to automatically compensate for changes in the tool displacement while TWI have demonstrated a roller system that maintains the tool position above the weld plate.

Tool design

The design of the tool is a critical factor as a good tool can improve both the quality of the weld and the maximum possible welding speed.

It is desirable that the tool material is sufficiently strong, tough and hard wearing, at the welding temperature. Further it should have a good oxidation resistance and a low thermal conductivity to minimise heat loss and thermal damage to the machinery further up the drive train. Hot-worked tool steel such as AISI H13 has proven perfectly acceptable for welding aluminium alloys within thickness ranges of 0.5 – 50 mm but more advanced tool materials are necessary for more demanding applications such as highly abrasive metal matrix composites or higher melting point materials such as steel or titanium.
Improvements in tool design have been shown to cause substantial improvements in productivity and quality. TWI has developed tools specifically designed to increase the depth of penetration and so increase the plate thickness that can be successfully welded. An example is the "whorl" design that uses a tapered pin with re-entrant features or a variable pitch thread in order to improve the downwards flow of material. Additional designs include the Triflute and Trivex series. The Triflute design has a complex system of three tapering, threaded re-entrant flutes that appear to increase material movement around the tool. The Trivex tools use a simpler, non-cylindrical, pin and have been found to reduce the forces acting on the tool during welding.

The majority of tools have a concave shoulder profile which acts as an escape volume for the material displaced by the pin, prevents material from extruding out of the sides of the shoulder and maintains downwards pressure and hence good forging of the material behind the tool. The Triflute tool uses an alternative system with a series of concentric grooves machined into the surface which are intended to produce additional movement of material in the upper layers of the weld.
Widespread commercial applications of friction stir welding process for steels and other hard alloys such as titanium alloys will require the development of cost effective and durable tools. Material selection, design and cost are important considerations in the search for commercially useful tools for the welding of hard materials. Work is continuing to better understand the effects of tool material's composition. structure, properties and geometry on their performance, durability and cost.

Welding forces

During welding a number of forces will act on the tool:

A downwards force is necessary to maintain the position of the tool at or below the material surface. Some friction-stir welding machines operate under load control but in many cases the vertical position of the tool is preset and so the load will vary during welding.
The traverse force acts parallel to the tool motion and is positive in the traverse direction. Since this force arises as a result of the resistance of the material to the motion of the tool it might be expected that this force will decrease as the temperature of the material around the tool is increased.
The lateral force may act perpendicular to the tool traverse direction and is defined here as positive towards the advancing side of the weld.
Torque is required to rotate the tool, the amount of which will depend on the down force and friction coefficient (sliding friction) and/or the flow strength of the material in the surrounding region (sticking friction).

In order to prevent tool fracture and to minimize excessive wear and tear on the tool and associated machinery, the welding cycle should be modified so that the forces acting on the tool are as low as possible, and abrupt changes are avoided. In order to find the best combination of welding parameters it is likely that a compromise must be reached, since the conditions that favour low forces (e.g. high heat input, low travel speeds) may be undesirable from the point of view of productivity and weld properties.

Flow of material

Early work on the mode of material flow around the tool used inserts of a different alloy, which had a different contrast to the normal material when viewed through a microscope, in an effort to determine where material was moved as the tool passed.

The data was interpreted as representing a form of in-situ extrusion

Extrusion

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...

where the tool, backing plate and cold base material form the "extrusion chamber" through which the hot, plasticised material is forced. In this model the rotation of the tool draws little or no material around the front of the pin instead the material parts in front of the pin and passes down either side. After the material has passed the pin the side pressure exerted by the "die" forces the material back together and consolidation of the join occurs as the rear of the tool shoulder passes overhead and the large down force forges the material.

More recently, an alternative theory has been advanced that advocates considerable material movement in certain locations. This theory holds that some material does rotate around the pin, for at least one rotation, and it is this material movement that produces the "onion-ring" structure in the stir zone. The researchers used a combination of thin Cu strip inserts and a "frozen pin" technique, where the tool is rapidly stopped in place. They suggested that material motion occurs by two processes:

Material on the advancing front side of a weld enters into a zone that rotates and advances with the pin. This material was very highly deformed and sloughs off behind the pin to form arc-shaped features when viewed from above (i.e. down the tool axis). It was noted that the copper entered the rotational zone around the pin, where it was broken up into fragments. These fragments were only found in the arc shaped features of material behind the tool.
The lighter material came from the retreating front side of the pin and was dragged around to the rear of the tool and filled in the gaps between the arcs of advancing side material. This material did not rotate around the pin and the lower level of deformation resulted in a larger grain size.

The primary advantage of this explanation is that it provides a plausible explanation for the production of the onion-ring structure.

The marker technique for friction stir welding provides data on the initial and final positions of the marker in the welded material. The flow of material is then reconstructed from these positions. Detailed material flow field during friction stir welding can also be calculated from theoretical considerations based on fundamental scientific principles. Material flow calculations are routinely used in numerous engineering applications. Calculation of material flow fields in friction stir welding can be undertaken both using comprehensive numerical simulations or simple but insightful analytical equations. The comprehensive models for the calculation of material flow fields also provide important information such as geometry of the stir zone and the torque on the tool. The numerical simulations have shown the ability to correctly predict the results from marker experiments and the stir zone geometry observed in friction stir welding experiments.

Generation and flow of heat

For any welding process it is, in general, desirable to increase the travel speed and minimise the heat input as this will increase productivity and possibly reduce the impact of welding on the mechanical properties of the weld. At the same time it is necessary to ensure that the temperature around the tool is sufficiently high to permit adequate material flow and prevent flaws or tool fracture.

When the traverse speed is increased, for a given heat input, there is less time for heat to conduct ahead of the tool and the thermal gradients are larger. At some point the speed will be so high that the material ahead of the tool will be too cold, and the flow stress too high, to permit adequate material movement, resulting in flaws or tool fracture. If the "hot zone" is too large then there is scope to increase the traverse speed and hence productivity.

The welding cycle can be split into several stages during which the heat flow and thermal profile will be different :

Dwell. The material is preheated by a stationary, rotating tool in order to achieve a sufficient temperature ahead of the tool to allow the traverse. This period may also include the plunge of the tool into the workpiece.
Transient heating. When the tool begins to move there will be a transient period where the heat production and temperature around the tool will alter in a complex manner until an essentially steady-state is reached.
Pseudo steady-state. Although fluctuations in heat generation will occur the thermal field around the tool remains effectively constant, at least on the macroscopic scale.
Post steady-state. Near the end of the weld heat may "reflect" from the end of the plate leading to additional heating around the tool.

Heat generation during friction-stir welding arises from two main sources: friction at the surface of the tool and the deformation of the material around the tool. The heat generation is often assumed to occur predominantly under the shoulder, due to its greater surface area, and to be equal to the power required to overcome the contact forces between the tool and the workpiece. The contact condition under the shoulder can be described by sliding friction, using a friction coefficient μ and interfacial pressure P, or sticking friction, based on the interfacial shear strength &tor; at an appropriate temperature and strain rate. Mathematical approximations for the total heat generated by the tool shoulder Q_total have been developed using both sliding and sticking friction models :

(Sliding)

(Sticking)

where ω is the angular velocity of the tool, R_shoulder is the radius of the tool shoulder and R_pin that of the pin. Several other equations have been proposed to account for factors such as the pin but the general approach remains the same.

A major difficulty in applying these equations is determining suitable values for the friction coefficient or the interfacial shear stress. The conditions under the tool are both extreme and very difficult to measure. To date, these parameters have been used as "fitting parameters" where the model works back from measured thermal data to obtain a reasonable simulated thermal field. While this approach is useful for creating process models to predict, for example, residual stresses it is less useful for providing insights into the process itself.

Applications

The FSW process is currently patented by TWI in most industrialised countries and licensed for over 183 users. Friction stir welding and its variants friction stir spot welding and friction stir processing

Friction stir processing

Friction stir processing is a method of changing the properties of a metal through intense, localized plastic deformation. This deformation is produced by forcibly inserting a non-consumable tool into the workpiece, and revolving the tool in a stirring motion as it is pushed laterally through the...

are used for the following industrial applications:
Shipbuilding and Offshore

Two Scandinavian aluminium extrusion companies were in 1996 the first, who applied FSW commercially to the manufacture of fish freezer panels at Sapa

Sapa Group

Sapa AB is a Swedish manufacturer of extruded aluminium profiles. The company is a wholly owned subsidiary of the Orkla Group, and based in Stockholm...

, as well as deck panels and helicopter landing platforms at Marine Aluminium Aanensen, which subsequently merged with Hydro Aluminium Maritime to become Hydro Marine Aluminium

Norsk Hydro

Norsk Hydro ASA is a Norwegian aluminium and renewable energy company, headquartered in Oslo. Hydro is the fourth largest integrated aluminium company worldwide. It has operations in some 40 countries around the world and is active on all continents. The Norwegian state holds a 43.8 percent...

. Some of these freezer panels are now also produced by Riftec and Bayards. In 1997 two-dimensional friction stir welds in the hydrodynamically flared bow section of the hull of the ocean viewer vessel The Boss were produced at Research Foundation Institute with the first portable FSW machine. The Super Liner Ogasawara at Mitsui Engineering and Shipbuilding

Mitsui

is one of the largest corporate conglomerates in Japan and one of the largest publicly traded companies in the world.-History:Founded by Mitsui Takatoshi , who was the fourth son of a shopkeeper in Matsusaka, in what is now today's Mie prefecture...

is the largest friction stir welded ship so far. The Sea Fighter
Sea Fighter
Sea Fighter is an experimental littoral combat ship under development by the United States Navy. Its hull is of a small-waterplane-area twin-hull design, provides exceptional stability, even on rough seas. The ship can operate in both blue and littoral waters...

of Nichols Bros and the Freedom class

Freedom class littoral combat ship

The Freedom class is a class of littoral combat ships built for the United States Navy.The Freedom class was proposed by Lockheed Martin as a contender for USN plans to build a fleet of small, multipurpose warships to operate in the littoral zone...

Littoral Combat Ship

Littoral combat ship

A Littoral Combat Ship is a type of relatively small surface vessel intended for operations in the littoral zone . It is "envisioned to be a networked, agile, stealthy surface combatant capable of defeating anti-access and asymmetric threats in the littorals." Two ship classes are the first...

s contain prefabricated panels by the FSW fabricators Advanced Technology and Friction Stir Link, Inc. respectively. The Houbei class missile boat

Houbei class missile boat

The Houbei class missile boat is a class in the People's Liberation Army Navy. The first boat was launched in April 2004 by the Qiuxin Shipbuilding Factory at Shanghai. The boats incorporate stealth features and wave-piercing catamaran hulls...

has friction stir welded rocket launch containers of China Friction Stir Centre. The HMNZS Rotoiti
HMNZS Rotoiti (P3569)
HMNZS Rotoiti is a Protector-class inshore patrol boat of the Royal New Zealand Navy. These boats perform border and fishery protection patrols.She was fitted out in Whangarei and on 20 November 2007 started contractor sea trials...

in New Zealand has FSW panels made by Donovans in a converted milling machine. Various companies apply FSW to armor plating for amphibious assault ship

Amphibious assault ship

An amphibious assault ship is a type of amphibious warfare ship employed to land and support ground forces on enemy territory by an amphibious assault...

s
Aerospace

Boeing applies FSW to the Delta II

Delta II

Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...

and Delta IV expendable launch vehicles, and the first of these with a friction stir welded Interstage module has been launched in 1999. The process is also used for the Space Shuttle external tank

Space Shuttle external tank

A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...

, for Ares I

Ares I

Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...

and for the Orion Crew Vehicle

Orion (spacecraft)

Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....

test article at NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

as well as Falcon 1

Falcon 1

The Falcon 1 is a partially reusable launch system designed and manufactured by SpaceX, a space transportation company in Hawthorne, California. The two-stage-to-orbit rocket uses LOX/RP-1 for both stages, the first powered by a single Merlin engine and the second powered by a single Kestrel engine...

and Falcon 9

Falcon 9

Falcon 9 is a rocket-powered spaceflight launch system designed and manufactured by SpaceX. Both stages of its two-stage-to-orbit vehicle use liquid oxygen and rocket-grade kerosene propellants...

rockets at SpaceX

SpaceX

Space Exploration Technologies Corporation, or more popularly and informally known as SpaceX, is an American space transport company that operates out of Hawthorne, California...

. The toe nails for ramp of Boeing C-17 Globemaster III cargo aircraft by Advanced Joining Technologies and the cargo barrier beams for the Boeing 747 Large Cargo Freighter

Boeing 747 Large Cargo Freighter

The Boeing 747 Large Cargo Freighter or Dreamlifter is a wide-body cargo aircraft. Cargo is placed in the aircraft by the world's longest cargo loader...

were the first commercially produced aircraft parts. FAA approved wings and fuselage panels of the Eclipse 500

Eclipse 500

The Eclipse 500 is a small six-seat business jet aircraft manufactured by Eclipse Aviation.Eclipse 500 became the first of a new class of Very Light Jet when it was delivered in late 2006...

aircraft were made at Eclipse Aviation

Eclipse Aviation

Eclipse Aviation Corporation was the Albuquerque, New Mexico-based manufacturer of the Eclipse 500 very light jet and also at one time proposed developing the Eclipse 400 single-engined jet....

, and this company delivered 259 friction stir welded business jets, before they were forced into Chapter 7 liquidation. Floor panels for Airbus A400M

Airbus A400M

The Airbus A400M, also known as the Atlas, is a multi-national four-engine turboprop military transport aircraft. It was designed by Airbus Military as a tactical airlifter with strategic capabilities. The aircraft's maiden flight, originally planned for 2008, took place on 11 December 2009 in...

military aircraft are now made by Pfalz Flugzeugwerke

Pfalz Flugzeugwerke

Pfalz Flugzeugwerke was a World War I German aircraft manufacturer, located at the Speyer airfield in the Palatinate . They are best known for their series of fighters, notably the Pfalz D.III and Pfalz D.XII...

and Embraer used FSW for the Legacy 450 and 500 Jets
Automotive

Aluminium engine cradles and suspension struts for stretched Lincoln Town Car

Lincoln Town Car

The Lincoln Town Car is a full-size luxury sedan that was sold by the upscale Lincoln division of Ford Motor Company; it was produced from 1981 to the 2011 model years...

were the first automotive parts that were friction stir at Tower Automotive

Tower Automotive

Tower International LLC is a global designer and producer of structural components and assemblies used by virtually every major automotive vehicle manufacturer...

, who use the process also for the engine tunnel of the Ford GT

Ford GT

The Ford GT is a mid-engine two-seater sports car. Ford Motor Company produced the Ford GT for the 2005 to 2006 model years. The designers drew inspiration from Ford's GT40 race cars of the 1960s.- Development :...

. A spin-off of this company is called Friction Stir Link, Inc. and successfully exploits the FSW process, e.g. for the flatbed trailer "Revolution" of Fontaine Trailers. In Japan FSW is applied to suspension struts at Showa Denko

Showa Denko

is a leading Japanese chemical engineering firm.Formed in 1939 by the merger of Nihon Electrical Industries and Showa Fertilizers, Showa Denko K.K. manufactures chemical products and industrial materials. SDK's products serve a wide array of fields ranging from heavy industry to the electronic...

and for joining of aluminium sheets to galvanized steel brackets for the boot lid of the Mazda MX-5

Mazda MX-5

The MX-5, also known as Miata in North America and Eunos Roadster in Japan, is a lightweight two-seater roadster, of front-engine, rear-wheel drive layout, built by Mazda in Hiroshima, Japan. The model was introduced in 1989 at the Chicago Auto Show...

. Friction stir spot welding is successfully used for the bonnet and rear doors of the Mazda RX-8

Mazda RX-8

The Mazda RX-8 is a sports car manufactured by Mazda Motor Corporation. It first appeared in 2001 at the North American International Auto Show. It is the successor to the RX-7 and, like its predecessors in the RX range, it is powered by a Wankel engine. The RX-8 began North American sales in the...

and the boot lid of the Toyota Prius

Toyota Prius

The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

. Wheels are friction stir welded at Simmons Wheels, UT Alloy Works and Fundo Rear seats for the Volvo V70

Volvo V70

The Volvo V70 is a mid-size five-door estate car / station wagon manufactured by Volvo Cars since 2000. It is closely related to the S70, S60 and S80 saloons, as well as the four-wheel drive Cross Country and XC70....

are friction stir welded at Sapa, HVAC

HVAC

HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...

pistons at Halla Climate Control and exhaust gas recirculation coolers at Pierburg. Tailor welded blanks are friction stir welded for the Audi R8

Audi R8

Audi R8 can refer to*Audi R8 *Audi R8 *Audi R8R, a Le Mans prototype built by Audi for the 1999 24 Hours of Le Mans*Audi R8C, a Le Mans prototype built by Audi for the 1999 24 Hours of Le Mans...

at Riftec. The B-column of the Audi R8 Spider is friction stir welded from two extrusions at Hammerer Aluminium Industries in Austria.
Railway Rolling Stock

Since 1997 roof panels were made from aluminium extrusions at Hydro Marine Aluminium with a bespoke 25m long FSW machine, e.g. for DSB class SA-SD

S-Train

The S-train network is a combined urban rapid transit and suburban rail network of Metropolitan Copenhagen, Denmark. It connects the city center with the inner suburbs of Copenhagen, and has close to half of the stations within the urban city. The first line was opened in 1934...

trains of Alstom LHB

Alstom

Alstom is a large multinational conglomerate which holds interests in the power generation and transport markets. According to the company website, in the years 2010-2011 Alstom had annual sales of over €20.9 billion, and employed more than 85,000 people in 70 countries. Alstom's headquarters are...

Curved side and roof panels for the Victoria Line

Victoria Line

The Victoria line is a deep-level London Underground line running from the south to the north-east of London. It is coloured light blue on the Tube map...

trains of London Underground

London Underground

The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

, side panels for Bombardier's

Bombardier Transportation

Bombardier Transportation is the rail equipment division of the Canadian firm, Bombardier Inc. Bombardier Transportation is one of the world's largest companies in the rail-equipment manufacturing and servicing industry. Its headquarters are in Berlin, Germany....

Electrostar

Electrostar is the name given to a series of related electric multiple-unit passenger trains manufactured by Bombardier Transportation at their Litchurch Lane Works in Derby, England...

trains at Sapa Group and side panels for Alstom's British Rail Class 390

British Rail Class 390

The Class 390 Pendolino is a type of train used in Great Britain. They are electric multiple units using Fiat's tilting train pendolino technology and built by Alstom. Fifty-three 9-car units were originally built for Virgin Trains from 2001 to 2004 for operation on the West Coast Main Line , with...

Pendolino

Pendolino is an Italian family of tilting trains used in Italy, Spain, Portugal, Slovenia, Finland, Russian Federation, the Czech Republic, the United Kingdom, Slovakia, Switzerland, China and shortly in Romania and Poland...

trains are made at Sapa Group Japanese commuter and express A-trains

Hitachi A-train

The A-train is a family of multiple units designed and built by Hitachi Ltd. initially for use on the railway system in Japan. The A-train family comprises trains for both commuter services and limited express services. Hitachi has given the family a modular design which enables both production and...

and British Rail Class 395

British Rail Class 395

British Rail Class 395 is a dual-voltage electric multiple unit used by train operating company Southeastern for its services along High Speed 1 and onwards to the Kent coast. The trains were built in Japan by Hitachi and shipped to the United Kingdom to operate new high speed domestic services...

trains are friction stir welded by Hitachi

Hitachi

Hitachi is a multinational corporation specializing in high-technology.Hitachi may also refer to:*Hitachi, Ibaraki, Japan*Hitachi province, former province of Japan*Prince Hitachi and Princess Hitachi, members of the Japanese imperial family...

, while Kawasaki

Kawasaki Heavy Industries

is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....

applies friction stir spot welding to roof panels and Sumitomo Light Metal

Sumitomo Group

is one of the largest keiretsu, founded by Masatomo Sumitomo.-History:The Sumitomo group traces its roots to a bookshop in Kyoto founded circa 1615 by a former buddhist priest,...

produces Shinkansen

Shinkansen

The , also known as THE BULLET TRAIN, is a network of high-speed railway lines in Japan operated by four Japan Railways Group companies. Starting with the Tōkaidō Shinkansen in 1964, the network has expanded to currently consist of of lines with maximum speeds of , of Mini-shinkansen with a...

floor panels. Innovative FSW floor panels are made by Hammerer Aluminium Industries in Austria for the Stadler DOSTO

Stadler DOSTO

The Stadler DOSTO or KISS is a bilevel electric multiple unit commuter train developed by Stadler Rail of Switzerland. It is operated by the Swiss Federal Railways under the classification RABe 511.-Name:...

double decker rail cars, to obtain an internal height of 2 m on both floors.

Heat sinks for cooling high-power electronics of locomotives are made at Sykatek, EBG, Austerlitz Electronics, EuroComposite, Sapa and Rapid Technic, and are the most common application of FSW due to the excellent heat transfer. The FSW process is also used for IGBT coolers at Sapa Group.
Fabrication

Façade panels and athode sheets are friction stir welded at AMAG

Austria Metall AG

AMAG is situated in the village of Ranshofen which is in Braunau am Inn and was founded in 1938.It is the biggest company in the Austrian Aluminium industry sector and is part of Constantia Packaging AG.- Companies:...

and Hammerer Aluminium Industries including friction stir lap welds of copper to aluminium. Bizerba#s

Bizerba

Bizerba GmbH & Co. KG is a German food processing equipment enterprise.It was founded in 1866 by the Bizer brothers in Balingen. Its name is a composite of the city's name and Bizer...

meat slicers, Ökolüfter HVAC units and Siemens X-ray vacuum vessels are friction stir welded at Riftec. Vacuum valves and vessels are made by FSW at Japanese and Swiss companies. FSW is also used for the encapsulation of nuclear waste at SKB in 50mm thick copper canisters. Pressure vessels from ø1m semispherical forgings of 38.1mm thick aluminium alloy 2219 at Advanced Joining Technologies and Lawrence Livermore Nat Lab. Friction stir processing is applied to ship propellers at Friction Stir Link, Inc. and to hunting knives by DiamondBlade.

External links

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