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Fred99
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  #2377111 17-Dec-2019 15:36
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MikeAqua:

 

An opinion is something like: "Stainless steel is a poor choice. It work hardens and becomes brittle"; but, in my case not a uninformed one.

 

 

I believe that the grade of SS (IIRC 301) tends to increase in tensile strength when work hardened, and also tends to "self heal".

 

So I read anyway, hopefully correct - as SpaceX is making rockets out of the same steel grade as claimed to what's going to be used for the production Cybertruck. Musk claims it costs US$3/kg.




Handle9
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  #2377112 17-Dec-2019 15:41
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RobDickinson:

MikeAqua:


Fred99:


But what if you're being chased on the moon?  The Cybertruck will work on the moon. What a time to be alive.



Having seen the panel gaps on Tesla's cars, I'm unlikey to chance a trip to the moon on one of their rockets.



 


ah you are one of those. mkay. 


 


Ignorant, uninformed and unable to cope with change. Odd website to be on.



Wow. What are you trying to prove? Mike's asking a few interesting questions but instead of engaging you're behaving in a totally patronizing and insulting way.

That doesn't generally go that well here.

RobDickinson
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  #2377116 17-Dec-2019 15:46
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Hes trolling.




Handle9
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  #2377119 17-Dec-2019 15:52
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I don't agree at all. Asking questions about the choice of materials or cost of tyres is hardly trolling.

MikeAqua
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  #2377136 17-Dec-2019 16:26
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Fred99:

 

MikeAqua:

 

An opinion is something like: "Stainless steel is a poor choice. It work hardens and becomes brittle"; but, in my case not a uninformed one.

 

 

I believe that the grade of SS (IIRC 301) tends to increase in tensile strength when work hardened, and also tends to "self heal".

 

So I read anyway, hopefully correct - as SpaceX is making rockets out of the same steel grade as claimed to what's going to be used for the production Cybertruck. Musk claims it costs US$3/kg.

 

 

Tensile strength isn't the issue.  It's vibration that does the damage. 

 

The steel gets brittles from work hardening and then vibration cracks it.  From a car's perspective things like driving down a corrugated road induce vibration.  I've seen trailers made of 304, which is very similar to 301 and they develop cracks.

 

Note that 304 has more chromium than 301.  301 and 304 self heal from a corrosion resistance perspective (scratches in the oxide layer self heal), but as far as I am aware not structurally. They aren't that corrosion resistant.  It's beautifully shiny and slightly black when new (nicer than 316) but dulls as the protective chromium oxide layer forms.  This may yellow over time. It does visibly rust in coastal climates.

 

 

 

 





Mike


kingdragonfly
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  #2377149 17-Dec-2019 16:43
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wellygary:

The European safety bureaucrats are not amused


https://www.autoblog.com/2019/12/16/tesla-cybertruck-european-safety-regulations/


"Teller said that based on what he knows of the Cybertruck, it wouldn't receive type approval for a mass-produced vehicle, and couldn't be sold in Germany"


 



I can see the complete lack of crumple zones as a bad thing, both inside and out.

The 1960s Formula 1 cars were very dangerous, for a lot of reasons. Two factors were there lack of crumple zones, and inability to shed parts when crashed, thereby transferring energy away from the driver.

Today's racing cars practically explode on crashes, and even the most humble economy car front end will squash will an over-ripe tomato in a front end collision to protect the occupants.

All the crash energy has to go some place, and air bags can only do so much.


 
 
 
 

Shop now for Lego sets and other gifts (affiliate link).
Obraik
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  #2377155 17-Dec-2019 16:49
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MikeAqua:

 

Having seen the panel gaps on Tesla's cars, I'm unlikey to chance a trip to the moon on one of their rockets.

 

 

Tesla doesn't make rockets 😉





Looking to buy a Tesla? Use my referral link and we both get credits


kingdragonfly
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  #2377156 17-Dec-2019 16:53
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Something for the kids to play with over Christmas. Would be a little better with a colour printer and cardstock paper, but any printer should be OK.

Make your own paper CyberTruck, fold up toy




MikeAqua
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  #2377158 17-Dec-2019 16:54
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Obraik:

 

MikeAqua:

 

Having seen the panel gaps on Tesla's cars, I'm unlikey to chance a trip to the moon on one of their rockets.

 

 

Tesla doesn't make rockets 😉

 

 

They have car in space and I guarantee it has lost it's internal atmosphere 😋





Mike


Fred99
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  #2377238 17-Dec-2019 18:31
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MikeAqua:

 

Fred99:

 

MikeAqua:

 

An opinion is something like: "Stainless steel is a poor choice. It work hardens and becomes brittle"; but, in my case not a uninformed one.

 

 

I believe that the grade of SS (IIRC 301) tends to increase in tensile strength when work hardened, and also tends to "self heal".

 

So I read anyway, hopefully correct - as SpaceX is making rockets out of the same steel grade as claimed to what's going to be used for the production Cybertruck. Musk claims it costs US$3/kg.

 

 

Tensile strength isn't the issue.  It's vibration that does the damage. 

 

The steel gets brittles from work hardening and then vibration cracks it.  From a car's perspective things like driving down a corrugated road induce vibration.  I've seen trailers made of 304, which is very similar to 301 and they develop cracks.

 

Note that 304 has more chromium than 301.  301 and 304 self heal from a corrosion resistance perspective (scratches in the oxide layer self heal), but as far as I am aware not structurally. They aren't that corrosion resistant.  It's beautifully shiny and slightly black when new (nicer than 316) but dulls as the protective chromium oxide layer forms.  This may yellow over time. It does visibly rust in coastal climates.

 

 

The work hardening is already done - it's cold rolled sheet, and probably a reason why the Cybertruck looks like folded Origami vs pressed steel panels on cars.

 

I seriously doubt cracking is a problem if it's going to be used in rockets.  The self-healing, I'm not sure if it's surface only. You'll have seen what happens when you overtighten 316 bolts and forgot to use some anti-seize - it's essentially cold-welding itself together. (That's actually a serious problem in a vacuum, without an oxide layer forming when there's surface damage from contact between metals, they can cold-weld themselves together).  Best I can make of Musk's rambling monologues etc is that he's using a standard 301 grade for now, but wants to reduce weight as well as cost.  Small differences in composition (and forming) can make big differences in properties. Some 304 RHS or whatever used in a structural beam on a trailer might be entirely different than 3mm cold-rolled sheet.  
I'm very skeptical of Musk, but so far he delivers.  That said, I wouldn't even be slightly surprised if he delivers a production "cybertruck" that bears only passing resemblance to the prototype.

 

 


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