Answer- stainless specification

From: <Al>
Date: Sat Jun 12 2004 - 16:08:00 EDT

Two answers;
first one is a common problem. when people say 316 or 304 it is a shortform of expression with an element of carelessness and associated significant risk when put on documents,especially engineering documents. We see it all the time.

A proper material description has two elements;

First what I call the "product form" , the second is the material composition.
when we say 304 or 316 we mean A-240-304 A or SA(for pressure material) product form =plate 240- or forging 182- or pipe 213-.
the second number is the material composition.

Both the first digits (the product form) amd the second digits (the material composition) are defined by an ASTM standard which is why they get an A-number. (actually thats been expanded now with many other prefixes and suffixes).

L is just a suffix. it means low carbon steel. There is carbon is all steel, carbon is up to 1%.
but "L" means low carbon. its actually ELC (extra low carbon especially carbon content in the welding rods) because its less than .03%.

Carbides will precipitate in significant quantities when ELC steels are heated and held in sensitizing temperatures. ie use them within their limits, but they are better than non ELC steels at temperature. This is clear from the Stress/strength charts.

ELC grades (eg.A213-304L , A213-308L) tend to be less crack sensitive on heavy sections and have better low temperature notch toughness.

Remember the key trick and trap is "L" in welding electrodes does not mean the same thing ,it means low HYDROGEN, and whole other topic.

please dont take this as a complete answer, need to read up on it or get help in properly specifying materials. There are many many issues. A materials person is a full time career and it really really matters. many many (and costly) failures are materials faults and problems.

-----Original Message-----
From: Jijoy Pillai [mailto:jijoy@mis.co.ae] Sent: Saturday, June 12, 2004 4:48 AM
To: Undisclosed-Recipient:;
Subject: [PipingDesign] stainless specification

Hai all,
I would like to know how to specify a stainless steel plate. For eg: If we say 316, 316L, 304, 304L, etc... What does this 316 and L stands for ?

Thanks in advance

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