GTAW OF 2205 PIPING

By pipewelder_1999 (****)

Date 04-21-2007 11:58

I have seen customers specifiy ER-NiCrMo-3 . This wire will also work fine with the CS test coupons. Any of the F-43 fillers will work for the WPQ's . Do you not have to qualifiy your OWN wps ?

By chuck meadows (***)

Date 04-21-2007 13:54 Edited 04-21-2007 14:00

Whip,
If you are required to use an Inconel product, then ERNiCrMo-3 (625) is the most used. The use of a nickel alloy, personally, concerns me. 2205 Duplex is a nitrogen alloyed material. The nitrogen gives added pitting corrosion resistance and added strength to the material. 625 has a slightly higher PREN (pitting resistance equivalency number) than the 2205, but the 625 also contains niobium. Now, niobium has a high affinity for the nitrogen in the 2205, and will deplete the nitrogen in the HTHAZ and will result in high ferritic zones and loss of corrosion protection and toughness. So, what is more important, a slightly higher corrosion resistance on the weld bead ONLY, or the loss of corrosion resistance and toughness in the HAZ? If there are going to be any problems in this type of weld, it is going to be in the HAZ, not the weld bead of 625. Personally, even though I have seen 625 specified to weld 2205 Duplex, I feel that the niobium in the 625 will have greater negative effects that if the correct filler metal (ER2209) for a 2205 was used. But, if that is what your contract specifies, then you must use it.

By whip

Date 04-21-2007 17:11

Thanks guys.The home home office is sending me the WPS. ALL Squared away and good to go.I wondered about that because of chrome myself. Soon as I finished the posting I wished that I could remember the operating Temperature of that system thought I would investigate if that was maybe the reason they want to use that filler?
TRYINGTOCATCHUPINALABAMA
WHIP

By chuck meadows (***)

Date 04-21-2007 21:10

Whip,
Duplex 2205 is not recommended at temperatures above approximately 550F. If they are using the Inconel for high temperature protection, they are pretty uninformed on the uses of Duplex. Even if using the 625, regardless the temperature, the problems, or potential problems are going to be in the HTHAZ, not the weld bead.

By welderwv (*)

Date 04-22-2007 01:03

Good Point Chuck

We used duplex 2205 in various tank applications and projects for powerplant emissions. In each case the operating requirement was for extreme cold. Most being partially filled with liquid nitrogen. From my understanding that was the purpose of chosing duplex 2205. I do remember engineers stating the advantages of this material in extreme cold conditions but that it was not designed for high heat applications. We used 2205 GMAW and FCAW electrodes.

By chuck meadows (***)

Date 04-22-2007 12:59

By "extreme cold", you don't mean cryogenic (-320F) do you? The very high amount of ferrite in a Duplex will likely have detrimental effects on the impact testing used to qualify cryogenic applications. The high ferrite content will likely have problems meeting the minimum 15 mils lateral expansion.

By welderwv (*)

Date 04-22-2007 23:48

It has been many years ago. I was the lead welder on the project and I worked on the bottom section since it was 100% RT. I was told that the bottom 10 foot of the tank was to be filled with liquid nitrogen. Now after your post I am not sure. Perhaps they use a liner or seperate container and our part was the shell. We did use 2205 solid and flux cored wire though I remember that. and we used pulse arc for the GMAW.

Out of curiosity what type of material would qualify for cryogenic conditions? And what code would be used for that? I am taking my CWI in May and am always curious to learn new things.

By chuck meadows (***)

Date 04-23-2007 01:45

Send me your e-mail address and I will send you a paper relating to filler metal selections for cryogenic services and applicable tests required. Click on my name and it will bring up my profile and my e-mail address.

Chuck

By js55

Date 04-23-2007 13:49

A thought here: ASME IX certainly allows using CS coupons to test welders for F4X fillers. However, keep in mind that the CS BM will make the test somewhat easier in that the CS BM will allow an easier fusion.
Now, I am certianly not arguing to insist upon nickel BM for performance testing since most contractors and fabricators will be reluctant to do so for obvious reasons, and have traditionaly used CS myself, but the person in charge of testing should be aware of this issue, in case any particular individual appears borderline. My thought is, if they are borderline with Ni on CS, they will certainly struggle on Ni to Ni.

By js55

Date 04-23-2007 13:52

Another issue is, if you use duplex as a performance test filler you may need to use longitudinal bends (or RT) as opposed to tranverse bends since the strength of duplex filler will be such that the CS BM will take the brunt of the bend (usually right at the fusion line) and therefore will not be representative of 20% fiber elongation.

By fredB Date 11-06-2007 18:43

Chuck,
Why is duplex 2205 not recommended at temps higher than 550f. Do you know of any effects brine with some C02 have on Duplex 2205