TIG filler rod suitable for welding API-5CT K55 case tubing 1

[Tony_Ike]

Dear all,
Please can anyone educate me of the suitable TIG filler rod for welding API-5CT K55 case tubing?

 

The question suggests that welding engineering is not at all your specialty. Succeeding in this is much more than a matter of picking the right filler, so please retain a specialist for this task.

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

 

[Tony_Ike]

Ironic Metallurgist, thank you for making out time to explain your point on my question. Unlike what you said, I have a good knowledge of welding but sometime there is need for further clarification with other professionals within the welding field because nobody knows it all. The main issue is that we have been working on other carbon steel pipes like A36, A106 Gr B, SA 570 Gr 70 etc but recently a customer came to us for a job that required the use of API-5CT K55 Casing pipe 6" diameter pipe and 12mm thickness. I have checked with AWS D1.1 and ASME Sec IX material grouping and found out that K55 material is not listed there. Though we have been using TIG filler rod ER70S-2 for the rooting of other carbon steel pipe earlier mentioned (A106 Gr B) but based on my knowledge I don't think it will still be applied for K55 material due to disparity in the tensile strength of both material. I have thought of using ER80S-D2 but still want to ask to be sure they are compatible.

 

No problem Tony,
Sorry I probably overreacted; there's been far too many amateurs on here recently seeking help for their daily work, for which they are clearly unqualified.
My first approach would be to find out what is standard in your industry, starting with your the supplier (probably a jobber, so maybe no help at all). Google might give up information if you are persistent and creative in your search terms.
If starting from first principles, I would follow Code logic, which is that the rated tensile strength of the filler metal should match or exceed that of the base metal, in the same condition (i.e., as-welded or PWHT). K55 has a UTS greater than 70ksi, so you are correct, standard 70ksi class fillers are inadequate. ER80S-D2 is a popular low alloy filler that also has very good impact properties, but I don't know if it will match the strength of K55.
There also exists the classification ER90S-D2 with the same composition, but AWS rules suggest it is used with an argon mix; i.e., not suitable for GTAW process. In the end you may end up going to a -G suffix classification, which compositions vary according to manufacturer ('G' is basically a wild card). At this point you need to obtain advice from the consumable maker (Lincoln, Arcos, Hobart, etc).
I'll be interested to know what you find.

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

 

[Dhurjati Sen]

Dear Tony_Ike,

You may take a leaf from the following thread:

[link thread292-437782]Link[/url]

Regards.

DHURJATI SEN

https://www.nace.org/people/dhurjatisen