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Tesla Cybertruck May Have A Rust Problem
(www.carsdirect.com)
This is a most excellent place for technology news and articles.
There's a fix, it just cost 6k...
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?
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...