Conducting testing on 300 series stainless steel - temperature and bullet test

[Newton]

I have been wondering a couple things, mostly how hot the CT will get in direct sun all day. (Also just thought of will it elongate or do temps need to be higher for that?)

UPDATE
12x12inch plate in sun for about 3-4 HOURS @ about 85F outside temp...
stock finish getting to about 150F
mirrored seems to be almost always 10-15 degrees cooler than the stock finish
the black vynl covered is getting up to 163F
the white vynl is about 40F cooler than the back



Any thing else y'all would like to have tested?

Of course this is just for fun and a bit of info. we don't know the alloy or if its heat treated,or do we? Elon does say "ultra hard 30x steel"
I guess I'll get a hardened sample to test, depending on what I can find (Unless some1 wants to let me in on the secret Sauce. I wont tell)
7/21/2020 looks like its a 304L basically the same as what im testing (but still dont know if its hardened)

1st test is showing:
After 1 hour in direct sun, no wind ambient temp about 85F on 12x12" 304 stainless
Mirrored finish is 128F brushed finished #4 sitting at 138F

Using a better thermocouple/thermometer than the 1st test. ...

2nd test mirrored and flat finishes after all day in the sun ambient temp 78f very slight breeze.
Mirrored : measured under the plate with k type thermocouple taped to it. 120f
Flat : on top (facing sun) 130.1 f
Under 129.4 f

some1 asked about magnitism- Its basically non existant, super strong neodymium can barely hold itself on

New surface temp test with vyln wrap tape type material on it. ( i figured painting wasnt really relevent.
Pic should be self explanatory but ill write the cliff notes here.

ambient temp about 80F
-White coolest 30-40F cooler than black
-mirrored next coolest
-unfinished surface 2nd hottest
-Black hottest

@ 10 minutes in sun: unfinished surface: 112.1F
Mirrored: 108.5F
Black vynl: 132.3F
White vynl: 101.8F

@30 minutes unfinished surface: 123.6F
Mirrored: 116.4F
Black vynl: 141.4F
White vynl: 112.1F

@50 minutes Unfinished: 124F
Mirrored: 120.7F
Black Vynl: 148.5F
White vynl: 108.3F

Ill do some 1 on 1 tests: 1 plate all black vs 1 plate all unfinished.
I think having the colors on 1 plate eventually (past 1 hour), started effecting the other temps. also will leave for 3+ hour to try an find a max temp

did a little tempering color test

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[Jhodgesatmb]

I have been wondering a couple things, mostly how hot the CT will get in direct sun all day. (Also just thought of will it elongate or do temps need to be higher for that?)

I'm going to get a couple 6x6 .12inch( or as near 3mm as possible)pieces of a 300 series stainless. Paint a piece black, do nothing to 1, near mirror polish 1. Maybe paint 1 white,test the temps. Also I'll shoot a piece with a 9mm.

Any thing else y'all would like to have tested?

Of course this is just for fun and a bit of info. we don't know the alloy or if its heat treated,or do we? Elon does say "ultra hard 30x steel"
I guess I'll get a hardened sample to test, depending on what I can find (Unless some1 wants to let me in on the secret Sauce. I wont tell)

What will it take to dent it? I know that these are small sample sizes but at 3mm I would expect it to be pretty hard to dent.

 

[Newton]

Good idea! I'm not sure if I can make it scientific, but hitting it with things at varying intensity could be fun and easy.

 

[VI Tesla]

I have been wondering a couple things, mostly how hot the CT will get in direct sun all day. (Also just thought of will it elongate or do temps need to be higher for that?)

I'm going to get a couple 6x6 .12inch( or as near 3mm as possible)pieces of a 300 series stainless. Paint a piece black, do nothing to 1, near mirror polish 1. Maybe paint 1 white,test the temps. Also I'll shoot a piece with a 9mm.

Any thing else y'all would like to have tested?

Of course this is just for fun and a bit of info. we don't know the alloy or if its heat treated,or do we? Elon does say "ultra hard 30x steel"
I guess I'll get a hardened sample to test, depending on what I can find (Unless some1 wants to let me in on the secret Sauce. I wont tell)

From what I gather it may be a 304 series so maybe try that.
Re: Elongation not certain but Elon picked stainless for Starship due it's heat and cold resistance. Apparently it really doesn't need the heat shield tiles to survive re-entry, of course they'll be on there because they want to use the ship over and over. I would think elongation wouldn't be a good thing for a star ship that's using super chilled fuel in stainless steel tanks

 

[VI Tesla]

My bet is black = hotest, white = coolest and stainless somewhere in between. Would be intersted it mirror polish is cooler than the control piece.
Have fun.

 

[Sirfun]

How about try to cook an egg on it?

 

[Newton]

looks like ill get some 304 and do the tests. if it fails the 9mm test, Ill get a 302 hardened. it seems 302 is the only hardened I can find.

@Sirfun sounds cool, ill do that too!

 

[ajdelange]

If you are going to shoot at it please keep safety in mind i.e. angle it so the bullet gets deflected into sand or something. Even doing that poses some risk. I actually shot myself (bullet fragment that did not penetrate but it still hurt) at an approved range.

 

[ricinro]

you can't heat treat 300 series SS but it can be work hardened somewhat. 301 can be hardened to full hard. I am not sure how you will work harden annealed sheet available at your local metal supply store.

https://www.metalsdepot.com/stainless-steel-products/stainless-steel-sheet-plate

 

[TyPope]

My bet is black = hotest, white = coolest and stainless somewhere in between. Would be intersted it mirror polish is cooler than the control piece.
Have fun.

This is counterintuitive, but the Space Shuttle had a black underside to help it get rid of heat.

 

[VI Tesla]

This is counterintuitive, but the Space Shuttle had a black underside to help it get rid of heat.

I think that's just the colour of the ablative tiles. I could be incorrect though.

 

[ajdelange]

Mirror polish and pure true white (albedo 1) would both reflect all visible radiation impinging on them and thus be the coolest. Black (true black) would absorb it all and thus be the hottest.

The ablative tiles on the space shuttle are not heated by radiation but by friction and are intended to shed that heat by ablating (hence the name). The black color (are they black at installation or only after being scortched?) would help them radiate some heat too.

 

[VI Tesla]

Mirror polish and pure true white (albedo 1) would both reflect all visible radiation impinging on them and thus be the coolest. Black (true black) would absorb it all and thus be the hottest.

The ablative tiles on the space shuttle are not heated by radiation but by friction and are intended to shed that heat by ablating (hence the name). The black color (are they black at installation or only after being scortched?) would help them radiate some heat too.

The Starship ablative tiles are black upon installation. SpaceX has been sticking them to the side of the SN series during cryogenic tests to play around with mechanical and adhesive options for mounting. Do they have to be black....I'm sure someone knows.
Guess I'd make them black as well so upon landing the shuttle doesn't look like a cooked marshmallow .

 

[TyPope]

Mirror polish and pure true white (albedo 1) would both reflect all visible radiation impinging on them and thus be the coolest. Black (true black) would absorb it all and thus be the hottest.

The ablative tiles on the space shuttle are not heated by radiation but by friction and are intended to shed that heat by ablating (hence the name). The black color (are they black at installation or only after being scortched?) would help them radiate some heat too.

They are black on installation.

 

[Revoltlution]

Shuttle tiles are black (another reason) to DUMP heat by radiation... Black body is most efficient.