Aluminium Welding

Facts about:

Aluminium fabrication

Member of the Linde Gas Group

CONTENTS

Introduction .......................................................................................................................... 3

Main users .............................................................................................................................. 4

Transport ............................................................................................................................... 5Motor vehicles .......................................................................................................................... 5

The all-aluminium car and the space frame concept ....................................................... 7The ULSAB concept: Steel vs. Aluminium............................................................................. 8

Marine ........................................................................................................................................ 6Trains.......................................................................................................................................... 8

Selection of joining process ........................................................................................... 10Tailored blanking ..................................................................................................................... 11Welding ...................................................................................................................................... 12

Weldability .................................................................................................................................... 12Resistance Spot Welding (RSW) ............................................................................................ 13MIG and TIG welding ................................................................................................................ 13Laser welding ................................................................................................................................ 15Friction stir welding ..................................................................................................................... 15

Adhesive bonding .................................................................................................................... 16Mechanical joining .................................................................................................................... 17

Clinching ........................................................................................................................................ 17Riveting........................................................................................................................................... 17

Cutting ..................................................................................................................................... 18Mechanical cutting ................................................................................................................... 18Water jet cutting ..................................................................................................................... 18Thermal cutting ........................................................................................................................ 18

Summary ................................................................................................................................ 19

References .............................................................................................................................. 20

© AGA AB 1996

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Aluminium and aluminium alloys are structural materials with manygood and useful properties:

• Low weight. The density of aluminium is only 1/3 of steel and thetensile strength ranges from 70 to 600 MPa.

• Low corrosion tendency. With a proper design aluminium doesnot corrode, due to the formation of an oxidised surface layer.

• High heat and electrical conductivity. Per unit weight, aluminiumconducts both heat and electricity better than copper.

• Good processing properties. Aluminium can easily be extruded toform profiles of desired shapes, thereby satisfying demands onde-sign flexibility.

• Good low temperature properties. Tensile strength increases atlower temperatures and, unlike many types of steel, aluminiumdoes not become brittle. This explains why containers fortransporting liquid nitrogen (temp –196°C) are made of alu-minium.

These are the most obvious advantages of aluminium as an engineeringmaterial. A factor that must be considered, however, is the low Young´s-elasticity modulus. It can in combination with high strength in somecases result in problems with rigidity. The low fatigue properties thataluminium exhibits must also be considered.

Introduction

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Aluminium is a rapidly growing material in spite of problems with thefluctuation in price, which in turn are a result of the variable supply.Growth is taking place primarily in the transport sector i.e. cars , buses,trains and marine vessels. The world production of primary aluminiumincreased over 400% from 1960 to 1990 and the average growth peryear is at present 4%. The total production in Western Europe was 3.5million tonnes in 1992, the same as the stainless steel production. Theconsumption amounted to 6.7 million tonnes. This figure is higherbecause it also includes recycled aluminium.1

Main users

0%Transport Mechanical

industryElectricalindustry

Householdand office

Packaging Others

5%

10%

15%

20%

25%

Main areas of application for aluminium

Figure 1. Areas of application.

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The main sector for growth is found in motor vehicles includingautomobiles and commercial vehicles (trucks and buses). The esti-mated consumption in transport (in ktonnes) is shown in the tablebelow.

Aluminium represents 3-5% of the total weight in an average automo-bile today. This figure has been constant during the last 20 year period,but today, the effort to improve fuel economy has promoted increaseduse of aluminium.2 If for example 200 kg of steel could be replaced by100 kg of aluminium, the break-even point where an aluminium carwould be economical lies at 36 000 km of travelling. The European fuelprice and the price of aluminium in relation to the price of steel aretaken into consideration, as is the required energy for the productionof primary aluminium. The expected fuel consumption is reduced by0.5 litres of gasoline per 100 km.

Transport

Motor vehicles

Figure 2. Estimatedconsumption intransport.

01990

Automobiles

Marine

Commercial Vehicles

Aerospace

Railways1000

2000

3000

4000

5000

1995 2000

ktonnes

6

Figure 4. Manufacturingprocess/market sharerelationship.

ALL ALUMINIUMBODY

DOOR

TRUNKLID

FENDER

HOOD

1990

50 kg/car

200 kg/car

1995 2000

Figure 3. Expected maximumaluminium weight in a car, 1990,1995and 2000.

The recycling possibilities are also impressive. At present 95% of thealuminium in old cars can be collected after dismantling and shredding.Almost all sorted aluminium is recovered after remelting, and twothirds of the aluminium foundry products go to the transport sector.Even though aluminium only accounts for a couple of percent of theweight of a car, it gives more than 50% of the value of the recoveredmaterial.3

A fair prognosis is that the amount, by weight, of aluminium in anaverage automobile will amount to 10% by the year 2000 and 15-20%by 2010. An example of this is that an average Volvo body structureconsists of 3% aluminium by weight and will, if the present develop-ment programs are followed, have 15% aluminium by weight.2

Manufacturing Market Share %Process

1990 2000

Extrusion 6 10Casting 78 72Forging 3 3.5Rolling 12 14Total 100 100

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The all-aluminium car and the space frame conceptAudi AG in Germany and Alcoa began discussions in 1982 to addressways of reducing autobody weight to improve the car frame´s stiffness-to-weight ratio, fuel consumption and emissions. Audi have, togetherwith Alcoa, developed a complete aluminium body for the Audi A8.

The space frame concept that the car is based on is a significant changefrom traditional manufacturing methods and materials used for theprimary structure of automobile bodies. Instead of spot welding 300stamped steel components together to form the structure of the car, only100 aluminium extrusions and interconnecting aluminium die castnodes are joined to form the space frame structure. This results in abody weight reduction of 35%, potential for increased stiffness,reduced tooling and high recycling value. 4

Alcoa opened a plant in April 1995 in order to supply the Audi A8 withaluminium, and they are planning to invest in a second plant with acapacity of 100 000 cars a year.

Volvo and Mitsubishi have co-operated in an all-aluminium car projectcalled the Access. Ford and Alcan are also planning a new aluminiumcar and 40 test vehicles have been built. Aluminium is also the choicefor electric automobiles. GM, Chrysler and Ford are presently lookingat manufacturing aluminium based electric cars.5

Figure 5. The Space Frame Concept.

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The ULSAB concept: Steel vs. AluminiumWhen it comes to producing a light-weight automobile, 32 steelproducers from 15 countries have co-operated in order to present acounter-move to aluminium light-weight automobiles. The design hasbeen developed by Porche´s engineering service unit, based in Troy,Michigan. They introduced the UltraLight Steel Auto Body (ULSAB).Besides the body weight reduction by up to 35% the cost is reduced by14% together with an improved torsional rigidity by as much as132%.6 This is achieved by using high strength steels and usingtechniques such as hydroforming, tailored blanking and laser weldingcombined with careful stress analysis and holistic design models.Holistic design incorporates viewing the body as a whole, rather thanas a collection of isolated modules or components.7

Aluminium plate and extrusions are used extensively in the superstruc-tures of ships where the designers wish to increase the above waterlinesize of the vessel without creating stability problems. Aluminium hasbeen used in shipbuilding since 1900 due to the good strength/weightrelationship and long life. These factors have enabled various types ofsurface skimming vessels, such as multihulled catamarans, in order toobtain more from the available power.

There are fewer than 10 shipyards working with large fast aluminiumferries and there is expected to be a global need for 170 ferries of the fastgoing type before the end of 2000, with the emphasis on ferries for morethan 100 cars. Stena AB have ordered four fast going catamarans fromFinnyards in Rauma, Finland, to serve the route between England andIreland. This is to be the largest single object ever built in aluminium,with a weight of 3000 tonnes consisting of 1000 tonnes of aluminiumextrusions and 1000 tonnes of sheet aluminium. The shipyardKarlskronavarvet in Karlskrona, Sweden is building 10 coastguardvessels for the Swedish coastguard in aluminium, using 10-12 tonnes ofaluminium per ship.8

The off-shore industry utilises aluminium in applications such ashelicopter platforms, walkways and catwalks, ducts and louvres.Aluminium accommodation modules have been installed on the Snorreand the Statfjord ‘C’ platforms in the Norwegian sector of the NorthSea. An overall weight saving of 40% compared to an equivalent steelstructure has been achieved in the case of the Snorre accommodationmodule. The module was built using 20 different profiles and needed780 tonnes of aluminium, making it one of the largest aluminiumstructures when it was built. Many more applications are possible suchas fire walls, structural applications and external cladding of alu-minium on other metals.9

Railway vehicles are characterised by a long life-span, presently 30-40

Marine

9

years. A goal is therefore to minimise the maintenance costs and ensurethat the vehicle is able to withstand the long term dynamic load.10

Extruded aluminium profiles designed in a space frame concept aresuitable for railway vehicles, and there are many examples of recentcars being delivered with this design.

The low weight aluminium offers lower acceleration and retardationforces and lower track forces which in turn leads to less maintenance.Aluminium structures are therefore suitable for commuter trains. OyTranstech Ltd is the largest manufacturer of rolling stock in Finland.Transtech manufacture high speed train bodies of aluminium for theFinnish State Railways. Another example of an aluminium trainconcept is the Danish IC-3, of which over 100 trains have already beendelivered in 1995.11

Trains

10

There are a number of joining techniques available for use in aluminiumstructures. Since aluminium is rather new as a load bearing engineeringmaterial, much work is being carried out in order to compare differentadvantages and drawbacks for different methods.

For the purpose of comparison, joining methods are broadly catego-rised as either discrete or continuous methods. These terms refer to themeans by which forces are transferred through the joint. Discrete jointstransfer load only at specific points of contact between the componentsthat are connected, while the continuous joints provide a distributedload transfer over the region to which they are applied.

Joining technique selection is always based on several factors such asthe type of construction, the performance expected of the particularjoint, and the environmental protection required by the joint. The mainmanufacturing/assembly considerations that have to be taken intoaccount are:

• Ease of automation

• Thickness of parts being joined

• Production readiness

• Degree of access to the joint

• Capital investment costs

• Production per day

• Type of alloy

• Tolerances

• Joint length

One proposed method is to use the Quantitative Decision-Makingapproach12 which incorporates weighing of different factors (or consid-erations) against each other and making a decision after intuitivelysumming them up.

It is difficult, if not impossible, to estimate what joining techniques aregrowing most rapidly. This is because many techniques are rather newand have not been fully tested. When comparing different areas ofindustry where aluminium is extensively used, such as motor vehicles,aerospace, trains and marine, there are differences in joining methods.

Selection ofjoining process

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Joining methods

Fusion welding

Resistance welding

Adhesive bonding

Clinching

Riveting

Riveting

Fusion welding

Riveting

Adhesive bonding

Fusion welding

Area

Automotive

Trains

Aerospace

Marine

Tailored blanking is a concept incorporating joining blanks beforepressing, thus mixing different properties in the same blank. Tailoredwelded blanking of aluminium is a rather new field. Two main weldingtechniques are presently used: CO2 laser welding and TIG welding.Powerlaser Ltd., Waterloo, Canada has already established a facilityfeaturing CO2 laser welding of aluminium tailored blanks. For the TIGprocess, welding speeds of 6-7 m/min can be reached in a processpatented by Reynolds Metals, Richmond, USA.13 The main advantageof welding tailored blanks of aluminium is the possibility to varythicknesses. Typical thickness variations can be0.8/1.5, 1.0/1.5, 1.5/2.5 or 1.5/3.0 mm.2 Most interest in aluminiumtailored blanks can be found in the automotive industry for less loadedstructural components like deck lids and hoods. Further on there willbe an increased interest in aluminium for body components, doorinners and floor panels. A major field will be in electric cars.

Tailored Blanking

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AA Alloy type Typical applicationsterminology

1XXX Non-alloyed Packaging, decorative applications.

2XXX Copper Aircraft sheet construction.

3XXX Manganese General purpose applications, strip.

4XXX Silicon Filler wire.

5XXX Magnesium Marine components, pressurevessels, railroad cars.

6XXX Silicon+Magnesium Automotive frames.

7XXX Zinc High strength aircraft applications.

8XXX Other alloyingelements.

WeldabilityThe main groups of aluminium alloys are: Al-Cu, Al-Mn, Al-Si, Al-Mg,Al-Si-Mg, Al-Zn. In Europe, the most common type of classification forbase materials is the AA classification.

The properties of the different alloys are dependent on several factorssuch as hardening mechanism and heat treatment. The properties varyfor different alloys within each group and it is therefore difficult tocategorise the properties for each group.

The most rapidly growing alloys are the 3XXX, 6XXX and 7XXXalloys. Care must be taken when choosing the base material for aconstruction which is going to be welded. Not all good base materialshave good weldability. An example of aluminium alloys that aredifficult to weld are the copper bearing alloys (<4% Cu).

Weldability Holds for For example (ISO)

GoodNon alloyed Al All types Al99.7, Al99.5, Al99.0

Non hardenable Al Most types AlMn1, AlMg4.5Mn

Hardenablen Al Some types AlMgSi, AlSi1Mg, AlZn5Mg

ReducedNon hardenable Al Some types with AlMg (1-2%)

low Mg content

Hardenable Al Alloys with Cu, AlCuMg, AlCuMgSi,Pb, (Zn) AlCuMgPb, AlCuZnMg

Welding

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Resistance Spot Welding (RSW)RSW was one of the first joining techniques considered for aluminiumautomobile fabrication, mainly due to the fact that it has been soextensively used for joining steel auto body sheet. RSW is generally notsuitable for joining extrusions and castings, and is therefore not theprimary joining process chosen for space frame fabrication. It is,however, often used for assembling aluminium sheet parts in spite ofproblems with diffusion and extensive electrode wear. While electrodewear limits electrode life to 10 000 spots when welding steel, typicalelectrode life when welding aluminium is 1000 spots.14 RSW can onlybe used to make flange or lap joints. Butt, tee and edge joints are notpossible. This often limits RSW use or requires compromise in design,as does the fact that both sides of the joint must be accessible.

Non-destructive testing of resistance spot welds is very difficult.Though many methods have been developed, no technique has provento be reliable. Quality criteria must therefore be based on processcontrol, including welding parameter control and control of the sheetsurface condition.

Advantages Disadvantages

• Low deformation • Production cost investment• Known process • Mechanical properties• Easy to automate • Requires surface preparation

Spot welding is used on the Audi A8 in areas which are not accessibleto punch-riveting. A total of 500 spot welds are made (compared toover 4000 on the steel body).15,16 The aerospace industry utilises spotwelding and an example of this is the French jet aeroplane Caravellethat was spot welded. Swedish aeroplanes are also manufactured withspot welding, but riveting and adhesive bonding dominates.

MIG and TIG weldingMIG welding was developed in the 1940´s for aluminium welding.MIG welding is chosen instead of TIG welding for a plate thickness ofmore than 6 mm. TIG welding can be used for thicker material but theproductivity becomes too low. The lower range for MIG welding isaround 3 mm; the process is difficult to control at lower thicknesses. Ifpulsed MIG welding is used, thicknesses down to 1 mm can be welded.MIG welding is mainly chosen when high welding speeds or long weldlengths are of interest.17

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MIG welding has a number of characteristics which make it attractivefor automotive fabrication.


• Known process • Process control necessary• Easy automation • Fatigue performance• Good accessibility • May need post treatment

The designer must consider the effect of the heat on the mechanicalproperties. All aluminium alloys are strengthened by heat treatment,thereby degrading the mechanical properties in the HAZ resulting in areduction of strength by up to 40-50%.

Equipment for MIG welding of aluminium is somewhat different fromthat for steel. Water cooled torches are necessary in order to carry thehigher welding currents required and wire feeders should be of thepush-pull type.

Aluminium is very sensitive to hydrogen which forms pores and reducesstrength. It is therefore essential that no moisture is introduced into thegas delivery systems. This can be avoided by using the right materialsand by minimising the number of valves or connections.

Extensive surface preparation for MIG is not necessary. A simplestainless steel brush is usually sufficient. Oil, grease and other surfacecontaminants should also be removed.

MIG welding is the predominant joining process in marine applicationsdue to its reliability when correct procedures are employed.

The various problems which can arise have been studied in detail.Typical defects are shown in Figure 6.

On the Audi A8 the extrusions are joined to the space frame using 129 m ofMIG welding.2 Approximately 80% of these welds are made robotically.MIG welding is also suitable for joining space frames in railwayvehicles. Spot welding is not considered a suitable process.

Microporosity

Macroporosity

ShrinkageSoftening

Figure 6. Weld defects.

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TIG welding is applicable for thin sheets ≥0.7 mm and on short weldlengths. TIG welding is mainly used for sheet thicknesses ranging from1 to 3 mm. The method is excellent for applications where the root runcannot be welded with MIG due to e.g. a large air gap between thesheets. The biggest drawback with TIG is the low welding speed whichcauses dimensional instability, poorer mechanical properties and poorercorrosion resistance than MIG welding.

Laser weldingLaser beam welding is characterised by high welding speeds and deeppenetration, which makes welding of overlap joints possible. The highwelding speed makes the laser suitable for long, one-dimensionalwelding. Another advantage is that it only requires one-sided access. Itoffers new possibilities in light-weight structures where lapped jointsoften are used. Until recently, only CO2 lasers were used to weldaluminium due to the need for high power and beam quality that wererequired to reach the intensities needed for deep penetration. Nd:YAGlasers have recently undertaken a rapid development and can todayreach sufficient welding speeds (2-7 m/min) up to plate thicknesses of3 mm. When it comes to lasers, there are a few issues that must beaddressed:

1. More knowledge is needed to evaluate risks and potentials.

2. Design guidelines are needed.

3. The cost has to come down.

4. New technologies needed for fixturing.

Friction stir weldingFriction stir welding is a new method that incorporates a rotating toolthat is pressed into the joint between the parts to be welded. The toolis then moved along the joint and welds the material together throughthe friction energy created when the tool rotates against the material.The tool “stirs” the material with no melting. Welding speeds of up to 0.6 m/min have been reached on 5 mm thick aluminium.18


• No filler needed • Backing bar needed

• Fatigue resistance • Welding fixtures needed

• Easy to automate • Only to be used on straight flatworkpieces.

• Low tooling cost • Leaves an end hole when the tool is pulledout.

The method is ideal for long butt welds, but overlapping welds are alsopossible. The process was patented in 1992 by TWI.

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Adhesive bonding exhibits some advantages over other joining proc-esses.


• Corrosion resistance • Joint strength• Fatigue resistance • Durability• Metal property retention • Surface treatment• Joint stiffness • Fabrication and assembly• Join different materials • Quality assurance• Seals joints • Environment

Adhesive bonding is most appropriate for lap joints. Butt joints arealmost never used. The continuous nature of the joint implies that thejoint distributes stress better than discrete joining processes such asresistance spot welding and riveting. This means that adhesive bondingshows improved fatigue properties over these processes.13

Adhesive bonding means that the joint is made of plastics or rubberwhich implies that the joint is considerably weaker than the basematerial.

Joining of aluminium to other metals and non-metals using adhesivebonding is possible. The adhesive can also act as an electrical insulator,minimising galvanic corrosion problems, and as a joint sealant or anti-flutter agent.

There are many problems to solve before adhesives can find widespreaduse. The long term durability must be determined and non-destructivemethods must be defined. The maximum operating temperature liesunder 200 °C and the long cure times are also drawbacks for someapplications.

Adhesive bonding is often combined with riveting or welding to obtainthe benefits of both processes. The rivets or spot welds may also act asfixtures and clamp the bonded parts in position until cured.

Adhesive bonding might not seem to be a modern method of joiningwhen considering the recycling aspect. The metal is easily recycled, butthe adhesive is not. It is not, however, this problem that is considereda drawback; it is the way that the adhesives are produced that can causea problem from an environmental standpoint.19

On the Audi A8, adhesive bonding is applied around the door frames,floor panels, hood and deck lid. The aircraft industry has used adhesivebonding since the 1940´s and it is today used for joining a great deal ofthe load bearing parts of an aeroplane. A major problem with theadhesive bonding is that repairs of glued components are difficult toperform.

Adhesive bonding

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ClinchingClinches form a joint by pressing a punch on the plates and deformingthem in a die. One application is the joining of the hang-on sheets toextruded components in space frame designs if a suitable flange isincorporated into the extrusion. The process requires two-sided accessto the joint and the fact that most clinches pierce the metal can permitwater ingress. The machinery is capable of producing 40-60 clinchesper minute although the process has not been fully automated. TheAudi A8 has approximately 90 clinches.14


• Low energy consumption • Not suitable for visible areas• Low maintenance costs • Different tools for different tasks• Joining of different materials

possible• Only light cleaning necessary

RivetingRivets are generally available in two types: solid rivets and blind rivets.Both aluminium and stainless steel rivets are applicable for joiningaluminium, although aluminium rivets are preferred due to their lowercost. A special type of rivet is the metal piercing rivet. In this process nohole is drilled and the rivet is punched through the materials and thetubular end is flared open, thus locking the rivet into place. Since nohole is made, cycle times are shorter. Blind rivets have the advantage ofonly requiring access from one side. Rivets are only suited for lap orflange joints and the loading should be in direction.

Mechanical joining

Punch

Joinedparts

Die withoutmoveable parts

Figure 7. The principle of clinching.

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It is not possible to cut aluminium with a flame torch due to the fact thatthe melting point of aluminium is lower than the melting point ofalumina, which constitutes the oxide layer of the metal. The mostcommon method of thermal cutting is plasma cutting.

Mechanical cutting and sawing are still extensively used for cuttingaluminium sheet and extrusions. This has to do with the fact that it iseconomical and versatile. Aluminium can be worked with commonmachine tools found in most fabricating shops. Aluminium has oftenbeen compared to wood in that the same tools work for both materialsand at roughly the same cutting speeds. The cost of cutting aluminiumis about half compared to steel. The cutting zone quality is not veryhigh, so that other cutting methods often are applied when the materialis to be welded.

An alternative to the thermal cutting methods is water jet cutting. Themethod has proven to be very applicable to aluminium sheet andextrusion cutting. A high pressure water jet mixed with an abrasive isable to cut through 120 mm sheet with good results.20 The methodproduces a cold cut resulting in sharp corners.

Plasma cuttingThe material thickness range for aluminium plasma cutting extendsfrom thick foil to 150 mm. It must be taken into account, however, thatwhen cutting thick aluminium, the noise levels are extreme. Themethod is faster than laser in this range, but the quality of cut is lower.

Laser cuttingLaser cutting results in a high-quality cut, narrow kerf and low heattransfer to the workpiece. The high reflectivity of aluminium meansthat high power output is required to cut efficiently. The equipmentcosts are often very high for laser machines of this type.

Mechanical cutting

Water jet cutting

Thermal cutting

Cutting

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One of the most important key factors when using aluminium forstructural purposes is getting the joining right. Before selecting a joiningmethod, all the different aspects of each method must be evaluated aswell as the details to be joined and how the joint must work. Theselected method is often a compromise between speed, quality, cost andcompatibility with other steps in the production process.

Joining methods Advantages Possible problems/issues

Arc welding Known process Distortion, heat affected zone

Spot welding Low deformation, Tool wear, surface treatment,known process investment

Adhesive bonding Low deformation, can be Surface treatment, personalused with dissimilar metals safety, less accepted in structural

applications

Mechanical joining Low cost, light cleaning, Strength, galvanic effects, local(riveting, bolting, known process deformationclinching)

Friction stir welding Low tooling cost, good Backing bar needed, only forworking environment straight and flat workpieces

Laser welding High welding speeds, low Expensive equipmentdeformation

Summary

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1. EAA, European Aluminium Association.

2. Larsson, Johnny K, R&D co-ordinator,Body Engineering, Volvo Car Corporation AB, Göteborg,Interview 13/11 1995.

3. EAA, European Aluminium Association,Quarterly Report, first quarter 1994, p 4.

4. The Welding Journal, September 1993, note on p 83.

5. Andersson, Norbert,“Hollänska aluminiumbilen tar form”*,Ny Teknik, n 41 1995, p 36.

6. Martin, Darryl,“Steel industry to spend $20 million to build demonstrationultralight steel automobile”,INTERNET http://www.steel.org/ultralightnews/mainrel.html.

7. “Automotive Steel”,Ultralight Steel Body Consortium, brochure 1995.

8. Rosén, Svante, Karskronavarvet, Interview 21/11 1995.

9. DEAN, Robert,“Large aluminium extrusions in marine applications”,Marine Technology, February 1995, p 65-67.

10. Alvelid, Magnus, ABB Traction AB,“Skillnader mellan konstruktionsprinciper i stål, rostfritt ochaluminium”*,Svetsen n 3 1995.

11. Andersen, Nils-Erik,“Welded aluminium constructions on rail, road and sea”,Svetsaren v 50 n 3 1995.

12. Stol, Israel,“Selecting manufacturing processes for automotive aluminiumspace frames”,Welding Journal, February 1994, p 57-60.

13. Irving, Bob,“Welding tailored blanks is hot issue for automakers”,Welding Journal, August 1995, p 49-52.

* Only in Swedish.

References

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14. Armao, F.G; Long, R.S; Winter, E.F.M,“Joining techniques for aluminium castings, extrusions andsheet”,Fugen von Aluminium - Entwicklung und Chansen, Seminar25-26 Februar 1992, Neu-Ulm.

15. Andersson, Norbert, Ny Teknik, n 9 1994, p 10.

16. Wanke, R, Audi AG, Ingolstadt,“Fugen von Aluminium in der Großserie anhand praktischerBeispiele”,Fugen von Aluminium - Entwicklung und Chansen, Seminar25-26 Februar 1992, Neu-Ulm.

17. Runnerstam, Ola; Persson, Kjell-Arne; Lund, Trond;“The importance of a good quality gas shield”,Svetsaren v 50 n 3 1995, p 25-27.

18. Knipström, Karl-Erik,“New welding method for aluminium”,Svetsaren v 50 n 3 1995, p 5-6.

19. Diggelmann, Kurt,“Elatisches Verkleben von Aluminium im Farzeug”,Fugen von Aluminium - Entwicklung und Chansen,Seminar 25-26 Februar 1992, Neu-Ulm.

20. Mattson, Staffan,Aluminium Scandinavia n 6 1995, p 23.

AGA Gas AB • Sweden • Telephone: +46-8–706 95 09www.aga.se SK

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05en

g–02

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Member of the Linde Gas Group

Aluminium Welding

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