Tesla Cybertruck May Have A Rust Problem::One of the more standout qualities of the Tesla Cybertruck is its bare stainless-steel body. The stainless-steel body gives the Cybertruck a unique design, but
They keep using the words “stainless steel” which is an alloy created to be rustproof by removing the iron out of it. So how exactly is this stainless steel if it rusts?
There are different qualities of stainless steel. Remember kids, it’s stain less not stain never.
I guess there is still iron in it. Looks like they didn’t use an alloy with enough chromium for the application.
Well it has to be workable/formable, weldable and crack resistant under stress. Just welding most stainless mess with its ferrous properties.
Absolutely. Why would they call it less if it’s actually never? That would be exceptionally terrible marketing.
Yeah. I have a small pocket knife i carry everywhere, it is stainless. I’ve had it for years, and frequently bring it in the water with me clipped to my swim suit (incase i need to cut a tangled rope). I wash it like a dish with soap and water, i use it hard and put it away wet, and it has been fine for years and years.
After all this, i took it on a single trip in salt water, it spotted with rust that night.
I also have a Sig P938 SAS which has a stainless slide. I keep that dry and oil it on occasion, and yet that one spotted with rust within a year despite me taking good care of it. Luckily sig replaced the slide but this taught me one good lesson.
Different grades of stainless make it different grades of rust resistant. Kind of like calling IP67 electronics, like the iPhone 7, “waterproof” when they can only really withstand splashing. Some can get dunked, some can’t.
I’m being pedantic here, but stainless steel still has iron in it. The addition of chromium forms an oxide layer on the surface that prevents rust. If the body is rusting, that means they used a shitty grade of stainless. Stainless with an appropriate amount of chromium (and nickel) is expensive as fuck.
Stainless has chromium added. Iron is still the main element. Different stainless steels have various other elements added, like molybdenum. There’s a wide range of SS for various purposes depending on their formability, weldability, corrosion resistance, heat treatment or precipitation hardened. Some are mildly magnetic (400 series), others not (300 series). Big range of cost too. Not sure which one they used. There’s also a finishing process called passivation that should be used to reduce the likelihood of corrosion.
You are absolutely right, just for clarity:
Chromium needs to be > 12 weight-%. If you take 18 w-% Cr and 8 w-% Ni you get an austenitic steel which is (normally) neither magnetic nor able to be hardened.
And if you add 12 w-% Cr, you remove 12 w-% Fe. So formally this is right-ish too…
