Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

What is 30x steel?

This site may earn commission on affiliate links.
#2
steel comes in predefined mixtures such as 301, 302, 303, and such. Tesla made a custom mixture and replaced the 3rd digit with an X like you would a variable in math.

If you want to read about it, google grade 301 SS or grade 304 SS or any other number then realize Tesla hasn't told you exactly how 30x differs from the known types.
 
  • Informative
  • Helpful
Reactions: Fiddler, APotatoGod, E Dizzle and 4 others
#3
dhanson865 said:
steel comes in predefined mixtures such as 301, 302, 303, and such. Tesla made a custom mixture and replaced the 3rd digit with an X like you would a variable in math.

If you want to read about it, google grade 301 SS or grade 304 SS or any other number then realize Tesla hasn't told you exactly how 30x differs from the known types.
Click to expand...
Aha! So a vehicle made of 30x that produces no NOx.
 
  • Funny
Reactions: APotatoGod and ReddyLeaf
#5
dhanson865 said:
steel comes in predefined mixtures such as 301, 302, 303, and such. Tesla made a custom mixture and replaced the 3rd digit with an X like you would a variable in math.

If you want to read about it, google grade 301 SS or grade 304 SS or any other number then realize Tesla hasn't told you exactly how 30x differs from the known types.
Click to expand...
I read that in order to bend that 3mm thick SS, they had to deeply score the back sides of the bends. Sounds like a recipe for weakness unless the inside of the folds were later welded?
 
#7
Tam said:
"cold-rolled 30 times"

It's unclear whether one single layer of steel is rolled 30 times or

The sheet is rolled over and over again and each time it got another 1 additional layer on top for a total of 30 times to produce the final sheet with 30 layers thick.
Click to expand...

Just as likely that 30 times is as significant as 420. It is grade 30x SS so they could roll it 10 times or 20 times or 50 times but saw the pun/dual interpretation and said rolled 30 times.

Past a certain amount of working, the material doesn't improve much. It'd be nearly as good if they cold rolled it 25 times instead of 30.
 
  • Disagree
  • Informative
Reactions: Fiddler and APotatoGod
#9
Tam said:
"cold-rolled 30 times"

It's unclear whether one single layer of steel is rolled 30 times or

The sheet is rolled over and over again and each time it got another 1 additional layer on top for a total of 30 times to produce the final sheet with 30 layers thick.
Click to expand...
That's not how the cold roll process works. There's no layering. And it's called "three-o-ex" (just as you would say three-o-one for 301 SS, etc.) Those calling it "30-times" are uninformed. Cold rolling is done mainly to keep a tight tolerance (thickness/flatness uniformity in this case) and increased tensile strength. An added bonus is the immaculate surface finish as it comes off the rollers. It is possible to roll 30 times, but makes little manufacturing sense. Tolerance does not improve appreciably with additional rolls and also at the expanse of increasing internal stress.

Hot rolling, on the other hand, results in tolerance that are harder to control as the finished metal shrinks/warps while it cools. It also comes off the roller with an ugly oxidized finish. Ironically, cold rolling is usually a process that follows hot rolling.
 
  • Informative
Reactions: Fiddler, APotatoGod, E Dizzle and 1 other person
#14
A given alloy of stainless (as designated by the 301, 304, 316 etc numbers) can also be cold worked (rolled) to varying degrees of hardness. That is typically described by a simple fraction like 1/4-hard, 1/2-hard, or full-hard, expressed as relative fraction of the maximum hardness that can be achieved. While hardening increases the yield strength of the metal, it makes it less ductile. The yield strength is a lot closer to the ultimate tensile strength. It becomes somewhat "brittle". So when you do exceed the yield strength (to bend it), you quickly also exceed the tensile strength and it tears or cracks. You cannot bend it to a small radius (relative to the thickness) without cracking it.

…To make sharp bends, you need to make it thin enough. When the section is thin compared to the bend radius, you can get the metal to yield without generating enough strain on the outside radius of the bend to exceed the tensile strength and crack. That is why the scoring is needed,
 
Last edited:
  • Informative
Reactions: Fiddler, APotatoGod, E Dizzle and 2 others
#15
In regards to the alloy being the same as used in spaceships, the needs of a spaceship are a bit different than a vehicle, so if its adding cost to the vehicle, its a waste. Stainless alloys can be made that are specifically tuned for heat resistance - they maintain their strength at higher temperatures (as in thousands of degrees). Which is good for nuclear power plant plumbing and spaceships.

But high temperature strength is not needed for a truck exterior- you are not going to drive your truck at supersonic re-entry speeds leaving the skin red-hot.

The claim that the stainless is the same as used in the spaceships is a cool marketing gimmick, though.
 
  • Helpful
  • Funny
Reactions: APotatoGod and Snerruc
#19
Per Elon Musk at 22:04 in the SpaceX "Starship Update" Youtube video, he states "the best design decision on this whole thing is 301 stainless steel". Type 301 is an austenitic stainless steel contains up to 0.15% carbon, 16%-18% chromium, 2% manganese, and 6%-8% nickel (the rest is Iron and a few trace elements). 301 has been around for a long time and has been commonly used since at least the 1960s. It is primarily used in the cold worked condition. It can be strengthened by cold work to an exceptional extent.

For the Starship 301 SS, SpaceX is probably keeping a tight control on the Nickel content which greatly determines the ability to cold work the steel. They are then cold working the steel followed by stress relieving. I'm not sure to what degree they are cold working the steel, if you go too far it starts to get brittle. However, even in the Full-Hard state, with an tensile ultimate strength of 180-220 ksi, it still has a failure strain of about 9%, which is not bad. As Elon states, it does have pretty impressive cryogenic properties. At -400F, it has about 230% of its room temp tensile ultimate strength.

More info can be found in:
MMPDS Chapter 2 Steels - AISI 301
Aerospace Structural Metals Handbook Vol 2 - Code 1301
 
  • Informative
  • Like
Reactions: callmesam, APotatoGod, E Dizzle and 2 others
#20
cptcolo said:
Per Elon Musk at 22:04 in the SpaceX "Starship Update" Youtube video, he states "the best design decision on this whole thing is 301 stainless steel". Type 301 is an austenitic stainless steel contains up to 0.15% carbon, 16%-18% chromium, 2% manganese, and 6%-8% nickel (the rest is Iron and a few trace elements). 301 has been around for a long time and has been commonly used since at least the 1960s. It is primarily used in the cold worked condition. It can be strengthened by cold work to an exceptional extent.
Click to expand...

Isn't it crazy how Elon can probably quote materials Specs all day long, offf the top of his head?!?
 
You must log in or register to reply here.

Similar threads

Hookemhorns
Not an exoskeleton- wait say what?
Replies
48
Views
6K
Cybertruck
ZenRockGarden
ZenRockGarden
N
  • Question
Model Y Body: BY03 - What does Safety Net Body mean?
Replies
2
Views
1K
Model Y
newberry94005
N
B
What’s wrong with my Model Y?
Replies
3
Views
583
Service / Maintenance
Yelobird
Yelobird
K
Hit & Run: Tesla Insurance vs Tesla collision center
Replies
6
Views
1K
Service / Maintenance
Litigate28
Litigate28
S
What do you do (admin and members if they know) when a forum member passes away?
Replies
17
Views
943
The UK and Ireland
WannabeOwner
WannabeOwner
Top
Back
Blog
New
Forum list
Marketplace
Menu