In what seems like a never-ending quest to decrease the weight of automobiles, General Motors has announced that its Research & Development center has invented a welding technology that is expected to facilitate increased use of aluminum in future vehicles.
The new resistance spot welding process is an industry-first method to weld aluminum; the technique uses a patented multi-ring domed electrode that is able to do what smooth electrodes are unreliable in doing — welding aluminum to aluminum. The use of the welding technique can result in the elimination of two pounds of rivets from aluminum body parts (like hoods, liftgates, and doors) — eliminating the cost of adding rivets that are limited to the restricted range of joint configurations found on riveting guns. In addition, the rivets in aluminum parts make end-of-life-recycling more complex.
Using two opposing electrode pincers to compress and fuse pieces of metal together, spot welding utilizes an electrical current to create intense heat and form a weld. The process, according to GM, is inexpensive, fast, and reliable — and, until now, there was no way to robustly use it in a manufacturing environment. As such, the technology will give The General a unique manufacturing advantage that will grow in importance in the future. More importantly, the increased use of aluminum in vehicles promises to result in improved fuel economy and driving performance characteristics, such as acceleration, handling, and breaking.
Currently, the resistance spot welding process is already in place on the Cadillac CTS-V as well as the liftgates of the Hybrid variants of the Chevy Tahoe and GMC Yukon, but GM has plans to establish a more large-scale use of the technology in 2013.
Industry analysts expect the use of aluminum in vehicles to increase significantly over then next decade thanks to the specific promise of decreasing vehicle mass. A kilogram of aluminum, for instance, can replace 2 kilos of steel — effectively having the ability to cut a car’s weight in half. Aluminum also has other desirable properties: it’s corrosion resistant and offers substantial tensile strength at a low mass.
General Motors said it is open to licensing the welding technology for non-GM use in auto, heavy truck, rail and aerospace applications.
Comments
is that why malibu is lighter than Fusion?
I don’t think the new Malibu takes much advantage of aluminum… not sure what to attribute the Malibu’s lightweight nature when compared to the Fusion — but it might be that the Malibu is a tad smaller.
because the Fusion Titanium is almost 4000 lbs (at 3700lbs for AWD maybe thats the factor not sure for FWD but maybe a little bit heavier than Malibu though)
Aluminum suffers corrosion, it oxidizes, in fact the piece of Al in the picture are oxidized. Most people see corrosion as rust, but that is just iron oxidizing.
Andrew – and what do you make of that?
Make of what?.. The article said aluminum is corrosion resistant.
Aluminum corrosion just opens the door for other problems.. Such as paint bubbles. My CTS (aluminum hood) has a tiny bubble patch on the centre crease where it meets the strip of chrome trim above the grille. That’s just an example, it isn’t an isolated problem, do a google search and you’ll see.
this picture is from a mustang
http://articleurge.com/wp-content/uploads/2012/02/Mustang-Bubbled-Paint.jpg
Are you recommending not using aluminum? Is it not corrosion resistant?
I just wasn’t sure what you were saying. Still am not sure actually.
Aluminum is a fine material. Light and still maintains good structural qualities.
I guess it is corrosion resistant to a certain extent, but when most people read that they think corrosion proof. And they think it wont rust.
Well it won’t rust like iron (FYI, iron is what rusts in steel and is what gives steel it’s magnetic properties). Anything with iron is a ferrous metal, and will rust in the conventional way; turn red/brown and into flakes/dust.
Rust is just iron oxide. So rusting is just iron oxidizing. Aluminum oxidizes too, it doesn’t have iron in though (it is a non-ferrous metal) so instead of turning red and decaying, it gets ‘spotty’ and tarnished and turns white-ish. This is more or less how aluminum rusts. Aluminum rust = aluminum oxide.
Oxidizing (which includes iron rusting) only occurs when the metal is subject to oxygen (oxidize : oxygen.. get it lol?). When steel rusts it flakes away which exposes the under layers of steel to more oxygen so it rusts even more until everything is pooched.
Where as aluminum oxide doesn’t flake away, it ‘seals’ the aluminum and prevents the under layers from oxidizing more. This is where the whole corrosion resistance they talked about in the article comes into play. But this oxide “shield” doesnt help when it forms under your paint work and causes the bubbles like in the link i provided in my other post.
All it really takes is a stone chip or even a micro-hairline crack in the paint/clearcoat/primer to expose the bare aluminum to oxygen and start oxidizing.
Some of that may not be 100% scientifically fact, but it is the jist of the process. I graduated highschool 6 years ago and in terms of the main science groups (bio, chem, physics) have done nothing but physics and structural science in University since (Civil Engineering), so that is all memory from grade 12.
Does any of that help or just create more questions? I suck hard at explaining things/ trying to teach people.
Thanks for sharing, Andrew. If I understand correctly, what @Silent is asking is whether you’re recommending aluminum shouldn’t be used over steel, or vice versa.