Hi Duke,
TEG is not very corrosive, if you look at this data sheet (Watlow Corrosion Guide) the recommendation is that 316 S.S has a rating of “A-Good category ” in TEG. Please note these data are for general information and further guidance. The onus of acceptability is primarily with the process design /mechanical design personnel of the Engineering Consultant and client’s engineers.
You need to validate the information with your design team.
At the same time it does not harm to carry out ASTM A 262 Practice –E, IGC test (the most common IGC test for austenitic stainless steels) on the plates or weld coupons. You may please discuss this issue with your AI. Most of the austenitic stainless steels if manufactured and heat treated properly in the mill will invariably pass this test. However failure of this test may increase the potential to inspection hold ups.
Please check with the plate mill, on the chances of IGC practice E pass or fail criteria of the clad plates in case the AI insists the same. Same would be applicable for welding consumables also.
As for the statement below from UCL-32, it’s a generic statement to safeguard against improper design. It’s always a requirement in Corrosive media to match or overmatch the corrosion resistance of the base and weld metal to the process fluid involved. That’s why all the ASTM-A-262 tests (Practice A,B, C, D,E) are insisted by the designers.
Thanks.
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Engineering Specialist
Hamilton, Ontario, Canada
ca.linkedin.com/pub/pradip-goswami/5/985/299
From: Minh-Duc Pham [mailto:mdpham1@gmail.com]
Sent: Thursday, October 22, 2015 12:41 AM
To: pgoswami
Subject: Re: FW: 23770] Weld corrosion testing on an ASME cladded pressure vessel. (UCL-32)
Hi Pradip,
No weld corrosion testing is required in the project specifications and the client confirmed it.
Fluid is TEG (Triethylene Glyclol).
Design pressure/temp. : 42.2 barg/100 deg.C
Internal structured packing in 316SS
Cheers,
2015-10-22 10:42 GMT+07:00 pgoswami <pgoswami@quickclic.net>:
Hi Duke,
Did the project specifications or design documents called for weld corrosion testing What’s the service media?? Appreciate if you could specify the design requirements.
Thanks.
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Engineering Specialist
Hamilton, Ontario, Canada
pgoswami@quickclic.net
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Duke
Sent: Wednesday, October 21, 2015 7:03 AM
To: Materials & Welding
Subject: [MW:23770] Weld corrosion testing on an ASME cladded pressure vessel. (UCL-32)
Hi all,
We have manufactured a glycol contactor vessel using carbon steel plate with 316SS internal cladding (3 mm).
DNV-GL, the vessel 3rd party inspector, is asking for a weld corrosion testing.
The project specification/data sheets does not request any weld corrosion testing.
DNV-GL interprets the UCL-32 (Weld Metal Composition) of ASME VIII div. 1 as a corrosion testing requirement.
UCL-32 states the following :
Welds that are exposed to the corrosive action of the contents of the vessel should have a resistance to corrosion that is not substantially less than that of the corrosion resistant integral or weld metal overlay cladding or lining. The use of filler metal that will deposit weld metal with practically the same composition as the material joined is recommended. Weld metal of different composition may be used provided it has better mechanical properties in the opinion of the manufacturer, and the user is satisfied that its resistance to corrosion is satisfactory for the intended service. The columbium content of columbium-stabilized austenitic stainless steel weld metal shall not exceed 1.00%, except when a higher columbium content is permitted in the material being welded.
As you see, there is no mention of any corrosion test requirement in this article and the client confirmed that he does not require any weld corrosion testing.
In the same meeting, DNV-GL confirmed that he will not accept the contactor vessel.
I would like to have your interpretation and experience regarding weld corrosion testing of cladded ASME vessels.
Thank you.
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