48 replies to this topic

[MatsNorway]

How many decently known cars out there is fully made in aluminium?

I only know about the first gen Audi A2 and the A8 from the 90`s or early 2000. I am actually bit of a fan of the A2.

Edited by MatsNorway, 31 May 2013 - 20:15.

[Superbar]

Define "fully made"...

Honda/Acura NSX '90-'05

Jaguar XJ '03-'09

[rory57]

How many decently known cars out there is fully made in aluminium?

All aluminum bodyshells: also the original Honda Insight of about 1998 - 2005.
All aluminium chassis: Lotus Elise. Also had Aluminium brake discs - I heard the firm making the discs went out of business but were they a technical success?

[Lee Nicolle]

I feel the NSX still had a steel backbone though the majority of the structure was alloy. A horrendously difficult car to repair. And I hope attracts the proper insurance premiums as a fairly minor crash will write it off as a road car.
Bolt on alloy panels are ofcourse a different scenario though are still way more expensive and in the case of MX5s not much lighter anyway. About 1.5 kilos. But a LOT more expensive.

[MatsNorway]

Was thinking of a full alu chassie. I actually forgot the NSX. The A2 also get writhen off easily according to wiki. Due to the different skills and difficulties needed to fix aluminium.

Edited by MatsNorway, 01 June 2013 - 08:08.

[Wuzak]

What about Ferrari 550, 575, 599, 612, FF, F12, 430 & 458?

Edited by Wuzak, 02 June 2013 - 01:40.

[Greg Locock]

Aston Martins were often aluminium body panels, as was early Rangerover, all proper Landrovers and the renault dauphin from the 1950s.

Edited by Greg Locock, 02 June 2013 - 11:19.

[MatsNorway]

No sedans? I knew there where sports cars with it but not who.

[mariner]

The earliest - and most completley aloy car I can think of was the Panhard which had an aluminum chssis from teh 1930's and an al aluminium engine

http://www.thetrutha...ory-of-panhard/

Its easy to find " forgotten innovators" from the past but I think Panhard had the basics of mixed cast and sheet constuction 70 years before Audi, Honda or Jaguar

BTW on a slightly related subject I was looking at the workshop manual for the 1970's Lotus Eclat yesterday and it basically says that if the accident is bad enough to bend the suspension fulcrums just throw the whole chassis away , its non repairbale - perfect Lotus design - just strong enough to go round corners but not much more!!

[J. Edlund]

How many decently known cars out there is fully made in aluminium?

I only know about the first gen Audi A2 and the A8 from the 90`s or early 2000. I am actually bit of a fan of the A2.

All Audi A8 and A2 models are made of aluminum, so is the R8 and the TT is a steel/aluminum hybrid using a large portion of aluminum. Also made in aluminum are most late model Ferraris and Aston Martins and some Jaguar models. Fisker Karma was also made of aluminum. Some Corvette models, Lotus Elise on other models based on that car have an aluminum chassis. A large number of cars are partially made of aluminum.

I feel the NSX still had a steel backbone though the majority of the structure was alloy. A horrendously difficult car to repair. And I hope attracts the proper insurance premiums as a fairly minor crash will write it off as a road car.
Bolt on alloy panels are ofcourse a different scenario though are still way more expensive and in the case of MX5s not much lighter anyway. About 1.5 kilos. But a LOT more expensive.

The NSX used a full aluminum chassis. The weight saving offered by aluminum compared to steel is typically quite significant, about 50%. The added cost is about $2000 for a full aluminum bodywork/chassis, too much for a volume production car but not a major cost for a more high end model. Infact, for the latter the total cost can be lower due to lower tooling costs with aluminum.

As for insurance and repair costs that really isn't a problem. It's usually not economical to repair a used car with major bodywork damage anyway; most cars are written off and used for spare parts in such a situation. But if car is involved in accident, damage suffered by the car isn't the major cost for the insurance company.

[Lee Nicolle]

Aston Martins were often aluminium body panels, as was early Rangerover, all proper Landrovers and the renault dauphin from the 1950s.

Are you sure about Dauphines? A neighbour had one when I was young, and I raced against some too. They seemed to dent and repair like normal cars.

Old Landrovers were alloy panels, hard to repair the dents they inevitably get. And the steel ribbing corrodes out still, as on occasions does the alloy. I have seen a few with the alloy corroded through. Both salt and years of accumulated mud. One was terrible, though it lived in the open on a windswept coastal farm for decades. Purely a farm vehicle though.

As for the NSX an alloy chassis will be far greater than half the weight of steel to get the same strength.

[PJGD]

The design of the Panhard Dyna was due to Jean-Albert Gregoire who had designed several cars with cast aluminium chassis. Perhaps the most desirable was the Hotchkiss Gregoire, again with a cast aluminium chassis and alloy flat four engine. It won the Monte-Carlo Rally in 1949 and 1950. Of course, the Dyna did well at Le Mans in the Index of Performance too.

http://www.voitures-...m/biography.htm

http://en.wikipedia....chkiss_Grégoire

PJGD

[gruntguru]

As for the NSX an alloy chassis will be far greater than half the weight of steel to get the same strength.

How much greater?

[Greg Locock]

Are you sure about Dauphines?

No I'm not. I do remember that when BL were working on aluminium cars they bought a (non running and decrepit) 1950s French car as it was the only aluminium unitary bodied mass production car. I thought it was a Renault Dauphin but I know they were usually steel. Bit of a mystery.

[SimonW]

The new Range Rover and Range Rover Sport are both all aluminium - chassis and body panels. As are the Jaguar XJ and the F-type. The RR and RRS are each about 450kg lighter than their predecessors.

Simon

[Kelpiecross]

The new Range Rover and Range Rover Sport are both all aluminium - chassis and body panels. As are the Jaguar XJ and the F-type. The RR and RRS are each about 450kg lighter than their predecessors.

Simon

The only Al-bodied cars I have had something to do with are an early XK120 and a Lea Francis saloon. Both had done quite a few miles and both had very bad fatigue cracks in their bodies - especially above the wheel arches if I remember correctly. I don't know if Al body metallurgy has improved - but if it hasn't it would be unlikely that you would find a very high mileage Al-bodied car as you do with steel-bodied cars. If you can keep the rust at bay I suspect steel is the better material for bodies.
In my experience Al would not seem to be a great material for car bodies.

As an aside - back in the 1960's I could have bought the XK in fairly rough condition for $200 Oz - the same XK was restored and was sold many years later for $200,000 Oz - a thousand times as much as I could have bought it for.

[kikiturbo2]

Aston Martins were often aluminium body panels, as was early Rangerover, all proper Landrovers and the renault dauphin from the 1950s.

yes, and all modern Astons are full alu chassis + alu and/or composite body panels bonded on..

[Catalina Park]

The short lived Hartnett car in Australia used a lot of cast aluminium in the chassis. It was a Gregoire design.

[MatsNorway]

If strengthened with alu tubing surely a alu car would last for a very long time. crashes and stuff aside.

[7MGTEsup]

If strengthened with alu tubing surely a alu car would last for a very long time. crashes and stuff aside.

Aluminium oxidise quite badly so I'm not sure how they treat it to stop this happening.

[Magoo]

No I'm not. I do remember that when BL were working on aluminium cars they bought a (non running and decrepit) 1950s French car as it was the only aluminium unitary bodied mass production car. I thought it was a Renault Dauphin but I know they were usually steel. Bit of a mystery.

Yes it is. Fascinating, too. Not my area at all but it's too intriguing not to chase. It must have been done -- it would be too easy not to try it. To the moldy stacks...

[desmo]

Aluminium oxidise quite badly so I'm not sure how they treat it to stop this happening.

One can go a long way towards prophylactically preventing corrosion in most Al alloys by intentionally oxidizing it using an electrolytic anodizing process.

[mariner]

The Dauphine was very definitely NOt alu. It started as an all steel car and very rapidly become an iron oxide car. They were total rust buckets in UK weather. I once stupidly bought one to fix mechanically. The rear engine mounting rails rusted through before I had time to fix the engine!

Maybe the BL purchase Greg refers to was a Panhard?

I think one of the big diferences between today's Alu. cars like the Jag and older times is the development of high reliabilty structural adhesive which largely eliminate the problems of welding thin section aluminium. The aerospace industry has never, to my knowledge , tried to weld aircaft thin panels together on any large scale which probably speakes volumes.

[Bloggsworth]

Is it my faulty memory, or did the Rover 2000 originally have aluminium body panels bolted to a steel frame?

[Greg Locock]

I'll settle for a Panhard Dyna Z. http://www.flickr.co...zil/4414731043/ looks about right

Rover had a long love affair with aluminium, partly driven in the early 50s by government restrictions on the use of steel, would you believe.

[JacnGille]

The Dauphine was very definitely NOt alu. It started as an all steel car and very rapidly become an iron oxide car. They were total rust buckets in UK weather.

I remember being able to watch the road pass beneath us looking through the rust holes in the floorboards in ours.

[Lee Nicolle]

How much greater?

Probably 2/3 to 3/4. It makes me wonder when I see all this expensive material being used in cars today. Really how much weight do they really save? Modern steel is quite light and strong, yet easy to form.
As I stated before an [aftermarket] MX5 bonnet in steel was only marginally heavier than the original alloy. And sorry, no longer available.
Even back in the 70s when the McCormack Charger project was happening Chrysler stamped some panels from alloy for it, just skins ofcourse. They were lighter than the heavier guage steel ones in use at the time, though the weight saving was not huge. The loss when stamping was about 50% too. Fibreglass is lighter, though has to be thin. Carbon fibre or Kevlar a bit lighter again, though also quite expensive. And often shows the weave through the paint.

[Lee Nicolle]

Is it my faulty memory, or did the Rover 2000 originally have aluminium body panels bolted to a steel frame?

Some bolt on panels, I believe only on the earlier ones.

[Lee Nicolle]

I'll settle for a Panhard Dyna Z. http://www.flickr.co...zil/4414731043/ looks about right

Rover had a long love affair with aluminium, partly driven in the early 50s by government restrictions on the use of steel, would you believe.

It does look like a Dauphine, though I bet was a lot more expensive.

[Joe Bosworth]

Aluminium oxidise quite badly so I'm not sure how they treat it to stop this happening.

There is a group of aluminium alloys specifically formulated for salt water applications. These are widely used for both extrusion , sheet and and plates needs.

The sheets and plates of various thicknesses are used for ship and boat hull structures. These vary from the 3 meter fishing "tinny" to the commercial, military and very high end yacht.

From a corrosion standpoint there is no environment worse than a ship.

I am currently travelling half way around the world from my handbooks but can specify alloys on return id there is any interest.

Regards

Edited by Joe Bosworth, 05 June 2013 - 14:54.

[MatsNorway]

I would not mind hearing more about this. Also in relation to just treating the alu with paint and stuff.

[ray b]

alcoa made an all alloy unibody/frame for a fiero
I believe it was bonded not welded
but was only a gee look what we COULD DO EXPERIMENT

[J. Edlund]

Probably 2/3 to 3/4. It makes me wonder when I see all this expensive material being used in cars today. Really how much weight do they really save? Modern steel is quite light and strong, yet easy to form.
As I stated before an [aftermarket] MX5 bonnet in steel was only marginally heavier than the original alloy. And sorry, no longer available.
Even back in the 70s when the McCormack Charger project was happening Chrysler stamped some panels from alloy for it, just skins ofcourse. They were lighter than the heavier guage steel ones in use at the time, though the weight saving was not huge. The loss when stamping was about 50% too. Fibreglass is lighter, though has to be thin. Carbon fibre or Kevlar a bit lighter again, though also quite expensive. And often shows the weave through the paint.

How much weight do aluminum save? Well, there have been several studies on that subject. One such study was made by Ford which made an aluminum version of a 1993 Mercury Sable. The total saving in that case was 173 kg or 47%. 3.6 kg (57%) was saved on the fenders, 6.6 kg (55%) was saved on the decklid, 13.2 kg (59%) was saved on the hood, 14.5 kg (43%) on the front door, 8,5 kg (37%) on the rear door and 125.2 kg (46%) on the unitary body.

According to a paper by Honda parts designed primarily for rigidity such as the BIW 1 kg of aluminum replaces 1.66 kg steel. In strength limited parts the saving is generally larger, and the largest in cast parts designed primarily for geometry. Most studies seem to agree that the weight saving offered by aluminum in a car is in the range of 40 to 50%.

Aluminum also got a high specific energy absorption, so if you design a structure for stiffness, it usually offers a good crash protection.

Modern high strength steels are also quite difficult to form since they are not very ductile. Complex forms are generally impossible to make as coldformed steel will rather break than being formed.

[saudoso]

As mentioned by mariner and ray b,when I was at engineering school - and that was before the A8 hit the market - material science taught us Aluminium was great but welding most often than not would ruin any efforts on using it.

I'd be interested in knowing if this has changed.

Edited by saudoso, 15 June 2013 - 13:31.

[malbear]

Modern high strength steels are also quite difficult to form since they are not very ductile. Complex forms are generally impossible to make as coldformed steel will rather break than being formed.

when making motorcycle exhaust systems we use cold rolled 1.2mm mild steel as it forms easily and takes chrome very well. the other important attribute is its sound as aluminium and stainless add a high pitch overtone and sound tinny. copper is the best from a sound perspective but cost it too much. carbon fiber also sounds sreaching

Edited by malbear, 15 June 2013 - 21:47.

[Greg Locock]

Modern high strength steels are also quite difficult to form since they are not very ductile. Complex forms are generally impossible to make as coldformed steel will rather break than being formed.

HSLA is around 500 N/mm2, and with tradenames like Extraform 500 you can guess that they are working hard to emphasise their ductility. admittedly compared with a decent steel at 1100 or more they are leaving a lot of meat on the plate, but compared with the usual recycled razor blades and toasters at 200 it is pretty good.

I know that tool design software for stampings is big bucks these days, one of the huge downsides from losing our toolrooms is that much of the expertise in die design walks out the door.

[Lee Nicolle]

HSLA is around 500 N/mm2, and with tradenames like Extraform 500 you can guess that they are working hard to emphasise their ductility. admittedly compared with a decent steel at 1100 or more they are leaving a lot of meat on the plate, but compared with the usual recycled razor blades and toasters at 200 it is pretty good.

I know that tool design software for stampings is big bucks these days, one of the huge downsides from losing our toolrooms is that much of the expertise in die design walks out the door.

The joys of the motor industry. Some bean counter saves a few dollars by exporting such work overseas and the hands on experience with building, repairing and on occasion 'adjusting' the tooling costs far more in time and lost productivity.
When Holden used imported steel because of the Bluescope strike they had about a 20% loss rate with stampings and a good toolmaker may have been able to minimise that.
Is there any main tooling made here anymore? I don't think so.

[Joe Bosworth]

Back in post #30 i had commented as follows, "There is a group of aluminium alloys specifically formulated for salt water applications. These are widely used for both extrusion , sheet and and plates needs.

The sheets and plates of various thicknesses are used for ship and boat hull structures. These vary from the 3 meter fishing "tinny" to the commercial, military and very high end yacht.

From a corrosion standpoint there is no environment worse than a ship.

I am currently travelling half way around the world from my handbooks but can specify alloys on return id there is any interest."

I am now back and can add the following.

There are dozens and dozens of recognised aluminium alloys for a variety of uses. The major recognised repository for such alloys is the Aluminum Association now of Arlington Virginia but historically at Washington DC. The AA catagorises plate alloys and extrusion alloys with a four digit numbering system generally as follows:
1XXX for essentially pure alloys of more than 99% Al
2XXX for copper alloyed Al
3XXX for manganese alloyed Al
4XXX for silicon alloyed Al
5XXX for magnesium alloyed Al
6XXX for magnesium and silicon based Al
7XXX for Zinc alloyed Al
8XXX mostly reserved for litium based alloys

For greatest corrosion resistance we need to look to the 5 and 6 thousand alloys.

This is due to the fact that magnesium, aluminium and silicon are found adjacent to one another as atomic weights 12, 13 and 13. This means that they bind together with especially tight molecular structure.

Since the 1940s alloy 5083 has been recognised as the Al alloy most corrosion resistant. In fact it is over a hundred times more corrosion resistant than mild steels. (This is not to say that there have been developed some quite corrosion resistant steels. The best comes to mind as the steel that US Steel developed back in the 50s and 60s and which they used to construct their headquarters building in Pittsburgh's Golden Triangle.) Alloy 5083 was registered in 1954 and contains between 4.0 and 4.9% Mg, .4% Fe, .4 to 1.07% Mn, up .25% Cr, .25% Zn and bits of Cu,Si and Ti.

5083 also has exceptionally good strength characteristics.

In the 190s alloys 5383 and 5059 were registered as sound alternatives to 5083.

The big breakthrough with 5083 came with the development of sophisticated welding techniques. Its drawback historically was that important allo elements were burnt out during welding. A combination of using quite fancy gasses and higher order welding rods resulted in little loss of strength in the heat affected welding zones.

Though ships were constructed of Al back in the 1890s corrosion was a recognised problem. One of the more famous efforts was the America's Cup boat Defender in 1895.

The use of Al for medium size commercial vessels came to the for from 1977 and from the 1980s due largely by the efforts of Incat in Tasmania and Austal Ships of Western Australia. In recent years nearly 100 ships per year have been completed for military, ferry and the wealthy.

For those who wish to delve into this a bit further I recommend that you key in
http://www.aluminum....ate/default.htm
and find their Adobe File, Aluminum at Sea article at the bottom of the page. The AA also has a voluminous lot of chemical and structural detail of alloys.

Just for interest sake, I used very thin 5086 for a racing car body in the early 1960s and was appointed to one of the Aluminum Associations technical committes about 1968.

[J. Edlund]

HSLA is around 500 N/mm2, and with tradenames like Extraform 500 you can guess that they are working hard to emphasise their ductility. admittedly compared with a decent steel at 1100 or more they are leaving a lot of meat on the plate, but compared with the usual recycled razor blades and toasters at 200 it is pretty good.

I know that tool design software for stampings is big bucks these days, one of the huge downsides from losing our toolrooms is that much of the expertise in die design walks out the door.

These Days steels used in safety structurescan offer strengths much higher than 500 MPa.
http://www.ssab.com/...s/Docol-1500-M/

Figure 8 shows what can happen with a low ductility steel during manufacturing:
http://www.bssa.org...... Material.pdf

[Terry Walker]

Current Rolls-Royce Phantom and derivatives has aluminium chassis, body is mostly aluminium. Also, back in 1916, the Marmon 34 used ally engine, ally in chassis, and ally body, no mean feat for the nearly a hundred years ago!

Edited by Terry Walker, 23 June 2013 - 12:50.

[sportian]

Audi R8 is made in aluminiun, right?

[MatsNorway]

Audi R8 is made in aluminiun, right?

Seems correct
http://stadium.weblo...way_large26.JPG

Edited by MatsNorway, 28 June 2013 - 16:33.

[bigleagueslider]

The Corvette chassis, suspension and drivetrain are mostly aluminum structures.



The Lotus Evora chassis is also mostly aluminum:

[Rasputin]

An interesting aspect when discussing materials is always to compare the stiffnees (modulus) over Density;

Martensitic Steel: Modulus = 207 E9 N/m^2, Density = 7800 kg/m^3, gives Stiffness over Density = 26.5 E6

Titanium: Modulus = 116 E9 N/m^2, Density = 4500 kg/m^3, gives Stiffness over Density = 25.8 E6

Aluminium: Modulus = 70 E9 N/m^2, Density = 2700 kg/m^3, gives Stiffness over Density = 25.9 E6

Magnesium: Modulus = 45 E9 N/m^2, Density = 1750 kg/m^3, gives Stiffness over Density = 25.7 E6

Interesting, eh?

Edited by Rasputin, 29 June 2013 - 15:10.

[bigleagueslider]

An interesting aspect when discussing materials is always to compare the stiffnees (modulus) over Density;

Martensitic Steel: Modulus = 207 E9 N/m^2, Density = 7800 kg/m^3, gives Stiffness over Density = 26.5 E6

Titanium: Modulus = 116 E9 N/m^2, Density = 4500 kg/m^3, gives Stiffness over Density = 25.8 E6

Aluminium: Modulus = 70 E9 N/m^2, Density = 2700 kg/m^3, gives Stiffness over Density = 25.9 E6

Magnesium: Modulus = 45 E9 N/m^2, Density = 1750 kg/m^3, gives Stiffness over Density = 25.7 E6

Interesting, eh?

From an academic standpoint, factors like stiffness/density are indeed interesting. But the commercial automotive business is primarily concerned with other factors such as cost. Most production cars still use steel for the unibody structure and body panels. There are several reasons for this. First, the commodity price for steel is far more stable and predictable over time than other metals like aluminum. Second, it is currently much easier and cheaper to build a unibody from steel than from aluminum. Third, body panels made from steel tend to have better aesthetics than those made from aluminum or composite.

[Rasputin]

From an academic standpoint, factors like stiffness/density are indeed interesting. But the commercial automotive business is primarily concerned with other factors such as cost. Most production cars still use steel for the unibody structure and body panels. There are several reasons for this. First, the commodity price for steel is far more stable and predictable over time than other metals like aluminum. Second, it is currently much easier and cheaper to build a unibody from steel than from aluminum. Third, body panels made from steel tend to have better aesthetics than those made from aluminum or composite.

Which was actually my point, from a stiffness vs density point they are all equal.

[Canuck]

Third, body panels made from steel tend to have better aesthetics than those made from ... composite.

Apart from the 'Vette, a few sports car roofs and a handful of exotics, I'm not familiar with any production composite panels (ignoring the "dentless" rubber panels on grocery-getters). From my limited perspective I find that statement a bit bewildering. Surely the sexiest cars on the planet aren't uglier for being made with composites?

[Powersteer]

all new porsche carrera is about 80% aluminium chassis and body but the gains does not seem too apparent probably from manufacturers putting that weight advantage in other areas to develop. nvh for aluminium too is good, think the renault spyder did away with soft bushing on its suspension because the aluminium chassis absorb a lot of shock. magnesium suspension is adopted by pagani probably for this purpose, and light weight of course, to dampen shock going to that thin carbon fiber chassis.

[Rasputin]

When you behold my modulus over density comparison, one might get the impression those materials are all equal for the same purpose.

That is not the case however, when yield strength is playing tricks as well, a 7000-series Alu can have the same yield as a decent steel.

This is why they don't build aircrafts in steel anymore, it's okay for the wings to flex as long as they don't yield.

As for te F1 Alu-monocoques of the 70s, a steel one would have been unpractical as it should have been assembled in paper thin sheets.