309S and 310S 1

[Welder4956]

Does anyone know what the "S" in 309S and 310S stainless steels designates? I know for the 300 series materials that the "L" designates low carbon and the "H" designates a grade that has a minimum and maximum carbon limit for hight temperature creep resistance. The standard grades (i.e. 304, 316) that have a max. carbon of 0.08 have no letter designation. But the 309S and 310S have a max carbon of 0.08 and the 309/310 grades have a max. carbon of 0.12. Does the "S" indicate a "standard" carbon level?

 

[unclesyd]

309 and 309S are identical except that 309S had a lower carbon. The lower carbon content minimizes problems with carbide precipitation and greatly imporves weldability of the alloy.

The same holds for 310 and 310S SS.

 

[Welder4956]

Yes, I saw that. But what does the "S" stand for?

 

[strider6]

welder,

S means that the max %C is 0.08. Grade 310S is used when the application environment involves moist corrodents in a temperature range lower than that which is normally considered
"high temperature service".

Look at this datasheet for other info on 310S:

http://metals.lincdigital.com.au/files/ASM Grade Datasheets/Grade datasheet 310.pdf

Hope this help
Strider

http://www.corrosionist.com

 

[EdStainless]

The "S" itself doesn't mean anything. Originally it was for special, not L grade and not H grade. Today when you buy 310S you will get mid-range carbon levels. We see 0.03-0.06 most typically.

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Still trying to help you stop corrosion.
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or edstainless@earthlink.net

 

[Flesh]

EdStainless,

Curious. "Special" as in a certain product form, a single specific application, or...?

 

[EdStainless]

"Special" as in "we call our alloy something different from the other guys".
It is sort of funny, there are very special grades of 310 available. The NAG (nitric acid grade) with very low residuals is one example.

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Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net

 

[strider6]

I don't know what means S, but If you look at the composition you see that an S in terms of C content is a 0.08 max.

S

http://www.corrosionist.com