Tesla Model 3 Aluminum, Steel, High-Strength Steel Mix Revealed

Tesla Model 3


Tesla Model 3

Tesla Model 3 alloys

This is exactly how the Tesla Model 3 utilizes a state-of-the-art body design that marries super strength with lightweight blends at an economical price point.

Redditor User_Juan came across a Tesla Model 3 repair book and posted images showing the mix of metals in the Model 3.  The images, which made their way to Twitter and were further shared on Reddit and Imgur, were confirmed by Electrek to be official.

Tesla Model 3

Tesla Model 3 rear components

As you can see from the pictures, Tesla uses three different levels of steel strength in the Model 3. The automaker recently posted a video on Twitter comparing the new car’s side pole impact performance compared to that of a Volvo S60 (a vehicle that CEO Elon Musk considers the “second safest” car in the world).

Tesla has said that the Model 3 will be the safest car in its class and earn the National Traffic Highway Safety Administration’s 5-star safety ratings in all categories. According to Tesla, the vehicle is also expected to significantly exceed competitors’ ratings.

As you can also see from the images, the Model 3 uses very little aluminum. This comes as no surprise since aluminum is expensive and also difficult/pricey to repair. However, in areas where an impact is less common or would lead to a minimal chance of injury — like the trunk floor and the wheel wells — aluminum is used to keep the weight down. The base Model 3 weighs in at only 3,549 pounds, with the long-range model (larger battery pack) weighing 3,814 pounds.

Aside from the small amount of aluminum, the vehicle uses ultra-high strength steel for the frame (which will prove helpful in rollover accidents) and high-strength steel for the underbody area where the battery is housed. A milder steel is used in areas that need the ability to crumple or absorb impacts.

Tesla Service Center technicians will need to be aware of which types of alloy are in each area of the vehicle. Body shop repairs will be possible to all alloys except for the ultra-high strength steel.

Sources: Reddit, Teslarati, Electrek, Imgur

Categories: Tesla


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35 Comments on "Tesla Model 3 Aluminum, Steel, High-Strength Steel Mix Revealed"

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lots of cars are built like this now i believe. hell my CTS has a mix of aluminum and high strength steel

GM helped pioneer this sort of mixed material construction and a similar strategy to this was used on the construction of the Bolt and the Cadillac CT6.

Looks like it will be difficult to repair. Lots of ultra high strength steel. Pretty much any damage and its irreparable?


Are you trolls having a contest to see who can post the most ridiculous Tesla-bashing FUD?

Ultra High Strength Steel should be replaced by “sectioning.” Not pulled in a frame machine, which reduces tensile strength to standard steel levels.

If you repair instead of replace UHSS in a Model 3 you will make it as safe as Chevy 🙂


This kind of thing is common in cars now. The Bolt is the same way, I had a car repaired (not my Bolt) which had the same kind of issues. It cost a mint. Well, it cost the insurance company a mint.

HSS and UHSS don’t really increase safety as the author implies above. They reduce the amount of material needed versus mild steel. But while being tougher they also are more brittle and so you can’t do repairs on the material by pulling it back out like you can with mild steel.

It’s just part of the tradeoffs in cars now. And not just for Tesla.

Pushy, no need to call anyone a troll over this.

I thought “fred” was asserting that this makes the car un-repairable, as far as body work goes. If Fred was only trying to say that any damaged sections of ultra high-strength steel need to be cut out and replaced, rather than “repaired” by bending them back into place, then I do owe Fred an apology.

Excuse me. Where I said tougher I should have said stronger.

Obviously I get confused by the different measurements of materials.

But all you really need to know is either adding more material or changing materials can increase the strength of a structure. Adding more material keeps the same other characteristics intact (like how brittle/tough it is) but makes it heavier. Changing materials can make it stronger without making it heavier but in this case also increases the brittleness. So the material will perform the job it needs to do in a wreck but it might be damaged in a way which is not as easy to fix. So the parts have to be cut out and replaced.

It’s a tradeoff but the upsides should exceed the downsides thus making it worth it in the end.

And you know this through your many years in the auto repair industry?

Or is this part of “How to Troll” lessons?

So the Model 3 wound up with less aluminum than I expected, yet still manages to be lighter than a Model S. Congratulations to Tesla’s engineers!

That’s certainly one way that Tesla has been able to make a car at a much lower cost.

Thunderbirds are Go!

It’s smaller.

Sure, but Tesla has only said it’s 20% smaller. I’ve always wondered; does that mean 20% smaller by volume, which wouldn’t be that much smaller? Or is it 20% smaller in length and in width, which would be a 36% reduction in volume? That’s a decidedly non-trivial difference!

I don’t know if saving 1000$ was really worth it. Yes it is cheaper but not much and as a result corrosion is more likely over the years. All Aluminum also had the advantage of an easier recycling. Now they will have to go through a much more sophisticated materials separation process at the end of the life of the car.

I wonder how they prevent galvanic corrosion.

Lots of aluminum on the bottom connected to steel and exposed to salty winter road splash is a recipe for quick corrosion of the aluminum.

Paint the dissimilar metals and glue them rather then fastening, perhaps? Hmm. . .

They don’t weld them. They use fasteners (rivets, screws) of various sorts, sometimes just adhesives. When they meet there is something between the two to keep them from touching. Sometimes it’s adhesive, even if other fasteners are already used.

You can see some of this in the video on youtube of the BMW i3 being built I think.

Here’s a link talking a bit about it.


Tesla doesn’t always use fasteners and glue. They use Cold Metal Transfer (CMT) welding to join aluminum to steel in Model S and likely in Model 3 as well. Probably not in places that would be exposed to water.

That is cool to know.

I think Bolt has a big mix of materials too. It would be nice to know so people can compare.

Yeah, I found this Tesla bashing article at Ars Technical on Google News today: https://arstechnica.com/cars/2017/08/report-tesla-is-bleeding-talent-from-its-autopilot-division/ Of course, it’s far too cynical to suggest that all these biased so-called “news” stories are the result of Tesla short-sellers angry over how much money they’re losing over Tesla stock being on a long upward trend, isn’t it? 🙄 It’s amazing how much the Tesla bashers are making out of one single fatality by a car under control of Autopilot, while ignoring all the lives it has almost certainly saved already. If the NTHSA says that Tesla cars with Autopilot + Autosteer installed have an almost 40% reduction in accident rate over those which don’t, then simple statistics show it’s almost mathematically certain that Autopilot+AutoSteer has saved many lives. Quoting the Ars Technia article: “Weeks before the October 2015 release of Autopilot, an engineer who had worked on safety features warned Tesla that the product wasn’t ready,” the Journal reports. In a resignation letter, the engineer, Evan Nakano, warned about “reckless decision making that has potentially put customer lives at risk.” Yeah, well I thought Tesla should have waited longer before rolling out AutoSteer (Beta), too. But with only a single proven fatality and… Read more »

There was recent study that said that cars with adaptive cruise control and lane change monitors, reduce accidents by 40%, and lane change monitors.
Tesla is certainly saving lives.
I’m glad you appreciated the spirit of the article I sighted.

Its commentary on the WSJ article, which I finally got to read this morning (WSJ used to give access to their web site, which has stories a day early, for free, but apparently no longer does. I refuse to pay for the same stuff I get in print online). It basically says what we all know, that Tesla is a hard place to work, and the turnover is high. Elon was asked for comment about it, and basically said “you guys have printed nonsense about me before, and I doubt this time is different”. The best comment came from an analyst who said that he was glad that Elon is a slave driving boss and has put money into Tesla (as have I). I don’t pursue employment over there because they lowball salaries and I am stunningly overpaid, and happy to be so. But I invest in them and hope to get an M3 this year, with FSD (option). A good autopilot for my airplane costs between $10,000 and $20,000, does not include the GPS/moving map, and all it does is follow the course line given by the GPS. A Tesla AP does so much more than this it is… Read more »

Pretty much I would go along with that, except for the part about Mobileye. It’s pretty well accepted after dumping them Tesla has still not gotten back to where they were with that system.
Eventually they will, but Intel & Mobileye are not going away.

scott franco said:

“…what you DON’T read about in the article is that Tesla dropped Mobileye for Nvida, which is like dumping Don Rickles for Einstein.”

Well, that puts a very different spin on things than we’ve been reading in InsideEVs articles, which have — in my subjective opinion, at least — been saying that Tesla had to go back to square one with Autopilot, and is still struggling to achieve the same level of functionality they had with MobilEye.

Or at least, that’s the impression I’ve gotten from various InsideEVs articles.

So thanks for that different perspective, Scott! I’ll keep an eye out for more info on this subject. InsideEVs doesn’t always get everything right; perhaps they are missing the mark on this.

The Bolt EV structure uses 7 different types of steel. Aluminum for body panels. See link to Jeff Cobb’s Bolt first-review article with photos of the Bolt frame showing where the engineers decided to use the various types, along with a materials color-code key. Engineering every square inch to optimize that fine balance of cost, strength, safety, and weight.


The Bolt will require special techniques both for body work and and structural repairs. See link to article below.


I’m sure Tesla will have similar requirements for the 3.

So much misinformation in the comments its really hard to read.

The high strength steel was introduced by the steel makers to counter aluminum/plastics use. Its is NOT used to create a super strength car, but rather to allow thinner panels and beams and lighten the weight of the steel used. It was generally incorporated into cars in past years and is not used.

Basically the deal was (as offered to the car makers) before you go switching to expensive aluminum, pay a bit more and we will give you steel that can do the same job at nearly the same weight.

So where does that leave us?

Model 3: (long range, approx 70kWh) 3,814lbs
Model S: (70kWh) 4,410 lbs

So for 596lbs less, even though it uses way more steel.

“years and is not used” = “years”

So you are saying that Ford going to all Aluminium cab and bed is a mistake as GM has been saying. GM has been favoring a “mixed” approach where using multiple materials in area where each metal excels…

Sounds like a good strategy.

But I would imagine the process of “bonding” multiple type of metal/alloy together and repairing them would be more complicated.

Look what Audi did with the new A8. The car had for years a full aluminum body and was praised for it but with the newest generation they changed that to a smart mixture. “The right material at the right place” is a phrase currently often used for car designs. Aluminum is light but not really stiff nor strong. It is good for energy absorption, but with the years it is getting softer and softer.

With heavy electric cars you need a really strong and stiff roof structure for example and also special reinforcement elements to protect the battery. I am pretty sure there are several smart solutions in the body structure.

Eg I find it interesting that Tesla uses an aluminum beam as a crash impact structure (below the doors) (the German word would be Schweller but I am not sure for the english term, maybe it is close :-P)

You are right. Bonding is tricky but today this shouldn’t be a problem anymore. You can buy all the know how you need.

More problematic is the different thermal expansion. This differs between steel, aluminuium, Magnesium and if you use carbon this material is getting smaller with more heat.
This is the real challenge for the bonded junctions.

I’m no fan of steel. I have an all aluminum aircraft. You wouldn’t want an aircraft with steel in it. Its a misconception that aluminum is corrosion free. In fact it is always freeking corroding. The way to stop this is to paint all of the inside surfaces with anti-corrosion paint, the famous green paint you see in military aircraft. Most aircraft makers decided it cost to much to do that, and as a result all light aircraft suffer from interior corrosion with age. Another misconception is that fibreglass aircraft are lighter than aluminum. They are about equal. Carbon fibre can be lighter (and carbon fibre is just like fibreglass but with carbon fibre instead of glass fibre), but this is because the higher strength allows thinner sections. It is true that any time you join dissimilar metals there is galvanic corrosion issues. I’m not an expert on it, but imagine that various coatings (like paint) handle it. All cars, be it steel or aluminum, have a special corrosion issue under the car, where it is continually under attack by water and salt from the road. That is where underbody coatings become paramount. For the side panels of the car,… Read more »

I bet they saved almost 50lbs just making it not a hatch.

All that strengthening you have to do on the hatch to make it not wobbly and the chassis not wobbly with the hatch open (not a structural member). Then the equipment needed to prop that heavy hatch open (gas tubes, etc.). Longer wires to the taillights because they can’t run right from the quarter panel area into the lamps but have to run up to the hinge area and back. With all that you could add 50lbs easy I would think.

So they have done the layering of different types of steel to get max strength. This is good strategy.

From the weights, we see that there is a 265 lb diff between the standard and long range models for the 90 mile gain in range. That’s 3 lb / mile. Not bad.

“That’s 3 lb / mile.”

Or 12 lb/kWh for 4 mils/kWh efficiency…

The BMW i3 & i8 went another direction with a carbon reinforced plastic “frame” with attached aluminum suspension components and body panels. Lighter than high strength steel – thus the light curb weight and high electricity mileage.