Duplex, 304 SS and 316 SS Certification 1

[MDAust]

Hi There,
We have been made aware of an Operator that has some Duplex material with very poor toughness (> 0 Deg C). We are aware of this issue with A105 material where the chemical composition and assumed toughness is not true due to manipulation of the chemistry with Boron etc.
We have reviewed the Duplex material certificates from our various suppliers and there is a wide range of documentation delivery. The simplest is just a chemical composition with tensile and hardness values up to a suite of chemical composition: Charpy values, Heat treatment temperatures and times, and grain structure slides.
The base requirement within the Duplex, 304 SS and 316 SS standards appears to be just composition with additional certificates available via Suplimentary Testing - to be specified by the Owner.

Are the ASTM base requirements satisfactory or do we need to specify Suplimentary Testing to ensure material toughness.

Regards, Mark

 

[EdStainless]

For duplex you really should be specing A923 method B or C in order to assure that it was heat treated correctly.
The low toughness could be an indication of the presence of intermetallics. These will lower toughness and greatly lower corrosion resistance. The A923 B requires impact testing at -40 and gives minimum toughness values.
There is a great duplex guide published by IMOA

https://www.imoa.info/download_files/stainless-steel/Duplex_Stainless_Steel_3rd_Edition.pdf

With 304 and 316 the most common additional test is A262 testing for sensitization.

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P.E. Metallurgy, consulting work welcomed

 

[SJones]

ISO 17781
ISO 17782
NORSOK M-650
EEMUA Publication 218
IOGP S-563 - Datasheets ID141 to ID269 (free download - try Googling)

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[MDAust]

Thankyou to both EdStainless and Steve Jones for the information probided. Very Clear. Was not aware of those IOGP material datasheets. Mark