UNS vs SA Specs
UNS vs SA Specs
(OP)
I have a silly question in which I'm having a hard time wrapping my head around.
ASME Section II provides specs for different types of alloys. For example, SA-693 has to have a certain chemical composition, material properties, tolerances, etc. From what i know, SA-693 is Stainless Steel.
What's the difference between that and UNS numbers such as SS 316? Does SS 316 only specify the composition? Is SS316 just a different spec since its under AISI and not ASME?
ASME Section II provides specs for different types of alloys. For example, SA-693 has to have a certain chemical composition, material properties, tolerances, etc. From what i know, SA-693 is Stainless Steel.
What's the difference between that and UNS numbers such as SS 316? Does SS 316 only specify the composition? Is SS316 just a different spec since its under AISI and not ASME?
RE: UNS vs SA Specs
RE: UNS vs SA Specs
316L is just shorthand and not officially the name of anything.
AISI hasn't assigned names for about 50 years.
The ASTM and ASME specifications reference UNS designations, and some of them include a list of common names.
A product specification (SA693) contains product specific information.
How it can be made, how it needs to be tested (destructive and NDT), mechanical properties, and certification and reporting.
In ASTM/ASME there are general specs (A1066 for stainless tubing) that contain all of the tests and then product specs (A249) refer back to the general so that we don't have to repeat everything in every spec.
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RE: UNS vs SA Specs
Also note that you will often see alloy grades identified by their UNS designations in many ASTM/ASME (and other) material specifications. You should also note that the specification composition may vary slightly from the generic composition published in the UNS book. When this happens, you are to use the material specification composition to confirm conformance of composition.
RE: UNS vs SA Specs
If you want to put a proprietary alloy into an ASTM you must show that you have applied for a UNS.
30 or 40 years ago the EU agreed to start using UNS for alloys in exchange for cross linking specs.
They haven't started yet.
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P.E. Metallurgy, consulting work welcomed
RE: UNS vs SA Specs
RE: UNS vs SA Specs
The specs include ASME, ASTM, SAE (and AMS), AA, ACI, CDA, MIL, AWS, NACE, ISO, and a few others.
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P.E. Metallurgy, consulting work welcomed
RE: UNS vs SA Specs
RE: UNS vs SA Specs
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P.E. Metallurgy, consulting work welcomed