Alloy 825 application in Sour environment

[Krishnnaa26]

thread338-262770

The remarks column in Table A.13 of ISO 15156-3 permitting to use annealed alloys of Type 4a (Alloy 825) in sour environment without restriction on temperature, ρH2S, chloride concentration and in situ pH. But it is also indicating that no limits on individual parameters are set but some combinations of the values of these parameters might not be acceptable, in production sour production environment.

Table A.14 is specifying the environmental limits for cold-worked alloys, however, the table title includes "annealed" also.

1) Since Table A.13 is not specifying the limits on individual parameters, can the individual parameters specified in Table A.14 for alloys of type 4c, be considered for use of Alloy 825 in Region 3 sour service, without additional testing.
2) Can the limits specified in Table A.14 be considered for weld over lay of respective alloys (Alloy 825) as per A13.2 ( Corrosion-resistant weld overlays) of ISO 15156-3?
3) In the answer provided for "MP INQUIRY #2015-08" in "ANSI/NACE MR0175/ISO 15156-3:2015 Inquiries and Answers",
[.....though there are no environmental limits currently defined below 132°C for UNS N08825, there could be some combinations of parameters including elemental sulfur form (i.e. physically dissolved, solid or liquid) that may not be acceptable.], what is the intent of the word "including"?.
4) As per NACE Paper No. 10262 (Corrosion Resistance of Nickel Alloys and Super Austenitic Stainless Steel Weld Cladding as a function of dilution. By Dirk Aberle, Martin wolf, Friedrich Stenner), considering the dilution effects, can the Alloy 825 WOL be considered in Region 3 sour service(~150°C and 2bar pH2S, 17000ppm chlorides)in view of the lower PREN values in WOL.

 

[EdStainless]

3) In this use the word 'including' more likely means 'especially and you really need to pay attention to this'.
4) If the WOL does not meet the chemistry of the alloy then why on earth would you expect the same performance?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[SJones]

1) It depends whether you accept that, in fact, there are environmental limits for type 4a and 4b, and whether you believe that both chloride content and pH have no bearing on performance in H2S-containing environments.

2) No
You are invited to review the following (personal) exchange with the ISO 15156 Maintenance Panel:

Q: Further to the interpretation responses given to MP Inquiry #2013-02, is it to be taken that the heat treatment condition of the as deposited weld metal, that will also not comply with heat treatment requirements for certain materials listed in A.2 to A.11, will result in the same response, i.e. the cracking resistance is not addressed in the standard? If this is the case, should a note not be added to the standard to suggest to users that, if they are also seeking cracking resistance for the deposited weld overlay, then they should be looking to an Annex B methodology, or a documented field experience basis, to qualify the cracking performance?

A: It is correct that NACE MR0175 / ISO 15156-3 does not address the cracking resistance for as-deposited materials, including impact of heat treatments.

If the Inquirer wishes to consider the overlay as a barrier for cracking resistance, a ballot is required to define cracking limits for a specific as-deposited composition for a defined location within the weld. Testing according to Annex B or the use of documented field experience according to NACE MR0175 / ISO 15156-1 clause 8.2 should be performed.
The addition of a note to the standard will require a ballot. The ballot form and instructions can be found at..................

3)
The intent is to add consideration of elemental sulphur to combinations of temperature, chloride concentration, pH2S, and pH that, in themselves, might be unacceptable

4)
See 2) above


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.

 

[Krishnnaa26]

@EdStainless
Thank you for your quick response. Yes, I don't expect the same performance. I am trying to understand (or relate) 1st and 4th paragraphs of A.13.2.

@SJones

Great many thanks for your responses which are more helpful in understanding WOL applicability.

1) I think the parameters (pH and chlorides in presence of high pH2S coupled with high temperature) will influence the performance.

2) I have tried here "06. ISO 15156 Maintenance Panel exchange folder" but I could not find the relevant content. Not sure whether it is open to public.
If it is in public domain, please help to share the link.

3) It is clear now.

4) Clear.

 

[SJones]

2) The item is in the public domain because I have posted it on here. The full text is:

From: Rick Southard <Rick.Southard@ampp.org>
Sent: 14 July 2021 21:57
To: JONES STEVEN
Cc: metallum.anglia
Subject: RE: Request For Interpretation - ISO 15156-3 - A.13.2

Dr. Jones,

The MP has provided the following response to your inquiry below:

“It is correct that NACE MR0175 / ISO 15156-3 does not address the cracking resistance for as-deposited materials, including impact of heat treatments.

If the Inquirer wishes to consider the overlay as a barrier for cracking resistance, a ballot is required to define cracking limits for a specific as-deposited composition for a defined location within the weld. Testing according to Annex B or the use of documented field experience according to NACE MR0175 / ISO 15156-1 clause 8.2 should be performed.
The addition of a note to the standard will require a ballot. The ballot form and instructions can be found at MR0175 / ISO 15156 Ballot Proposal Form.”

I hope this helps!

Regards,

Rick Southard

Rick Southard | Standards Senior Editor
Association for Materials Protection and Performance
Tel: +1 281-228-6485
ampp.org | nace.org | sspc.org



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.