Duplex and ASTM G48-A Test 6

[iam42]

Guys,

I am really struggling on how to proceed with a weld procedure qualification that I am currently working on.

The material is 8" sch40 2205 Duplex. Our customer has a requirement for corrosion testing IAW ASTM G48 method A. His criteria for the test is testing at 35°C for 72 hours. The acceptance criteria is "No pitting or crevice corrosion in either the weld metal or HAZ is permitted"

I just received the test results and with my limited knowledge it does not look good. The test results are shown below.

If anyone know what is going wrong, I would really appreciate a push in the right direction!

Thanks

 

[pradipgoswami]

Hi Iam42,

Good to know that you had success at last and my suggestions had worked for you. Also thanks for your endorsements.You may keep in touch in my personal email: pgoswami@quickclic.net.

It would be good to stay in touch on nice technical issues in future.

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

 

[EdStainless]

Have you done mechanical testing of the welds?
And have you done any impact testing?
You should make sure that you meet A923 impact criteria.

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

 

[iam42]

Hi Ed,

The tensiles were 112,000 psi and the Impact testing was average 47 ft-lbs for the weld and average of 95 ft-lbs.for the HAZ.

 

[SJones]

Here is the link to the TWI work from the 90s:

http://www.twi-global.com/technical...fication-of-duplex-stainless-steel-weldments/

Feel free to compare it to the Aramco and NORSOK requirements.

I would be interested to know the details of the assessment of the initial failed test piece in so much as where was the "pitting observed." In a 50 mm x 25mm test piece there will be a fair amount of parent material available to contribute to the mass loss and provide an area for pitting. If it did contribute, why didn't it do so again in the second test?

The draft ISO 17781 further complicates matters by providing yet another variant of testing

http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=60525

It has just been revised and reissued to go to a second round of voting on the DIS standard after the first version received a significant negative reaction. A copy for review should be available from your national standards organisation.


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.

 

[sorg1]

Hello guys,

I am new here, so please apologize if my question in relation to the topic of iam42 should be shifted to a new thread.
However, following question from my side to you specialists:
What are your experience with this requirement (SAES-W-016: corrosion test per ASTM G48A at 35 C for 72 h) for so-called "off-the-shelf" Equipment?
The mentioned specification does not clearly distinguish between the type of "parts having Duplex", respectively give space of interpretation.
It is like "...welding and testing of special corrosion-resistant piping materials", and later on "...Any service that uses duplex stainless steels".

I completely understand that you can not give me a binding or 100%-sure statement. Kindly note, my question refers more to your experience.
The fact is, at the moment our pump suppliers as well as the valves&instruments suppliers (also big brands as e.g. Yokogawa, Emerson, Wika) struggle with the requirements.

Thanks in advance!