Desalination - Specifications for use of Super Duplex 2507 3

[CobusvanJ]

Hi,

My company is in the desalination industry, which I only joined recently from Oil & Gas. I have very little experience in the way of manufacturing of Super Duplex 2507 piping, so I really require some good advice.

We will be manufacturing the 2507 manifolds overseas, so I need to write a full material specification and welding requirements. What information do I have to make sure appears in this document?

Current available information:

Piping design is to ASME B31.3
Design pressure is up to 8000kPa at a design temperature of 60deg C
Welding will be to ASME IX
NDT will be to ASME V

I see on these forums and other research that ASTM A923 is recommended to ensure welds are not a point of corrosion attack, how do I properly specify the use of this document?

Are there any other recommendations?

 

[XL83NL]

Wow, thats a long shot. There's too much that can be contained in such a document. First I'd start by purchasing a copy of API TR 938 C. Second, review all topics here on eng-tips on 2507, and look for leads or links in which you can further dive into. Buy standards if you think theyre useful. Talk to your welders, for experience and problems, and call your materials suppliers (e.g. Sandvik) for more info. Review material datasheets for 2507.

 

[CobusvanJ]

Hi XL83NL,

I see API TR 9388 C is for the use of DSS in oil refining, isn't it a lot more stringent than I would need for desalination? The only concern I have is to eliminate or at least limit pitting and crevice corrosion, so I want the welding to be of a good quality.

Operating temperature is less than 60deg C and probably a lot lower in reality.

Maybe I didn't state my requirement clear enough. How would you specify to a manufacturer what you would require on top of the specifications I listed above?

Should I just request that welding comply with ASME IX, ASME V and ASTM A923? Or is that too basic? The problem I have is that I do not have the time to study A923 as the project is kicking off in a bigger way much quicker than expected...

 

[DekDee]

cobusvanj,
It seems you have been put in a position (or you have put yourself in) that you are inexperienced in.
1 Follow everything XL83NL has stated
2 Realise that welding does not have to comply with ASME IX, ASME V or ASTM 923
3 Your welding must comply with B31.3, your welding procedures and welder qualifications must comply with ASME IX, your NDT must be in accordance with ASME V and a supplementary requirement is welding procedures must meet the requirements of ASTM 923.
4 If "The problem I have is that I do not have the time to study A923 as the project is kicking off in a bigger way much quicker than expected... " then you are in for a shitload of trouble
Good luck,
Regards,
Shane

 

[XL83NL]

Welding cant comply to A923. Welds can be tested to A923.

I recommend you get a copy of TR938-C and just read it. Allthough TR938-C is for O&G, it has basic requirements found in all industries. It's good to understand that. Especially for someone working with, and making specifications for the use of DSS, I would consider it mandatory you have those standards (such TR938-C) and understand them as well. (Unexperienced) work with DSS involves a lot of risks which you wont find until it's too late. If you dont have the time now, hire an expert to do the work for you, and teach/mentor you as well during his consultancy work, so you get a more basic understanding.

Maybe metengr or SJones can come in and provide their 2 cents; Im sure they can give you a more valuable reply based on their years of experience. The above is how I work with duplex, and how I started working with it. It has thought me the basics.

4 If "The problem I have is that I do not have the time to study A923 as the project is kicking off in a bigger way much quicker than expected... " then you are in for a shitload of trouble

Exactly, well put.

 

[metengr]

CobusvanJ;
Very good advice provided above. If I were you, I would hire a materials/welding engineer experienced with duplex stainless steel to develop a specification and you can be mentored along the way. Your risk is too great to go at this alone or using this forum.

 

Just to throw a spanner in the works, ASTM A923 was not intended for testing welds, but it has frequently been applied to them, with sometimes erratic results in terms of correlating with real world performance.
Owner's specifications can be poorly written, with unrealistic requirements that (for example) do not recognize the subtle differences between welding processes.
Take metengr's advice and retain a welding engineer experienced with navigating the minefield of duplex SS welding issues.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

CobusvanJ,
If you don't either hire a consultant or do a lot of studying yourself you will be in serious trouble.
Using dome form of testing as par to of the weld qualifications is a very good idea.
But there are two different tests, even though they are both done in FeCl solutions.
A923 (either corrosion or low temp impact) is designed solely to evaluate the detrimental effects of secondary phases. This is really what you need to include. These intermetallic phases will hurt both corrosion resistance and material properties.
The other tests that you see run are for corrosion resistance. The differences are related to sample prep (A923 requires a cross section with fresh ground surfaces) while corrosion tests usually want to test the 'as used' surfaces.

https://www.twi-global.com/technica...fication-of-duplex-stainless-steel-weldments/

https://www.materials.sandvik/conte...44f04d0/sav0049_whitepaper_welding_150606.pdf

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[pradipgoswami]

Hi CobusvanJ,
The flavour of API-TR-938C is more for the downstream industries, refining, petrochemicals.This may be used to form the basis of writing a design specification. However additional documents may be required to be referred.

A lot of design requirements on the use of DSS/SDSS in desalination plants are based on the design concepts adopted for Offshore/Upstream Oil and Gas Industry.

There're experienced engineering companies involved in these areas. Engaging their services might help.

I would say perhaps for the specified design temperature(60DegC)passing the Pitting corrosion test(ASTM G48A) could be an extreme challenge. You may have to keep Zeron 100 in mind also

Here're some useful papers which may be of help to you. However as advised engaging a competent welding/metallurgical engineer may be of immense help.

https://www.neonickel.com/wp-conten...-Duplex-SS-in-the-Desalination-Industries.pdf

https://store.nace.org/the-selection-of-materials-for-seawater-cooling.

Thanks


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[CobusvanJ]

Thanks to everyone for the responses.

 

[SJones]

ISO 17782
ISO 17781
NACE Corrosion 2012, Paper 1096
Avesta - How To Weld Duplex Stainless Steels

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

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