Is intergranular corrosion test required for duplex steel

[mrmalcolm]

Dear Sir,
Duplex stainless steel can easily pass the intergranular corrosion test in ASTM A262 actual E. If the duplex stainless steel has already undergone ASM G48 pitting corrosion test, is intergranular corrosion test required for duplex steel?
Thank you

 

[EdStainless]

No, you don't do A262 on a duplex.
You do a A923 on duplex to check for detrimental phases.
Similar to a G48, but different.
It requires full cross sections and freshly ground surfaces.
Or low temperature impact toughness.
Don't allow passing based on microstructure.

 

[mrmalcolm]

No, you don't do A262 on a duplex.
You do a A923 on duplex to check for detrimental phases.
Similar to a G48, but different.
It requires full cross sections and freshly ground surfaces.
Or low temperature impact toughness.
Don't allow passing based on microstructure.

Thank you. For type approval tests of duplex stainless steel, including chemical composition, mechanical properties, detecting detrimental intermetallic phase according to ASTM 923, pitting corrosion test according to ASTM G48.However, intergranular corrosion according to ASTM A262 is not required. Is it correct?

 

[EdStainless]

Correct.
The other thing that you want is to verify the A:F ratio.

 

[SJones]

This may help: ISO 17781

 

[Vahid.A]

As EdStainless and SJones mentioned, sigma phase formation in duplex stainless steels should be evaluated. For quality control of duplex materials, we refer to ISO 17781 and A923. Note that this phase can lead to localized depletion of alloying elements, a phenomenon known as sensitization. To assess the extent of depletion, an electrochemical test called DLEPR (Double Loop Electrochemical Potentiokinetic Reactivation) is used, as outlined in ISO 12732.