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Up Topic Welding Industry / Technical Discussions / welding of dissimilar metals
- - By pradeep4u (*) Date 12-28-2022 05:34
Dear all
i want to know that what is filler wire and electrode we use for welding  p11 and  a106 pipes and filler wire and electrode for p11 and p22  pipes.  p22 and p91, 106 and p91. Is there is any code/standards which  tells  which electrode to be used for different metals
Regards
A.Pradeep
Parent - By Jovi Zhu (**) Date 02-20-2023 14:12
Hello, Check AWS D10.8 for recommended filler metals for each combination.

Note that the material grades you mentioned are all ferritic and they are considered "similar" metals.

In certain areas such as power boiler industry dissimilar metal joints (DMWs) refers to Ferrtic to Austentic metals, such as welding G.91 to 300 series.
Parent - - By Jim Hughes (***) Date 02-21-2023 19:09
Pradeep4u,
If you are qualifying procedures then there are some resources out there especially when It comes to welding grade 91 or grade 91 to any other material.  During your research anything by EPRI or Bill Newell. Bill owns Euro-Weld. They are one of the leading suppliers of filler metal for the materials and the combination of materials you mention.  AWS 10.8 is a good start but that specification is lacking in some regards.
You need to understand for instance, you can't weld or at least should not be welding Grade 91 material to 300 series SS. EPRI and if you go to the Euro-Weld web site has information about why. 
I can give you some typical filler metal based on what you have in this post. P11 to A106=ER80-B2 for TIG or GMAW, P11 to P22 ER80S-B2, P22 to P91=ER90S-B3. I would not recommend P1 to P91 or as I already said P91 to 300 Series SS should have a transition piece in between. both can be a piece of P22 or P11.
If you need assistance my e-mail is jimhughes71@hotmail.com
Parent - By Jovi Zhu (**) Date 02-22-2023 12:58
Hi Jim,
Thanks for adding the ideas.

I have to point out from my years of exp working with US based companies that in boiler industry using 300 series SS in superheater or reheater will call for joining these ss tubes inevitably to ferritc nozzles of header pipes of especially Gr.91 materials.

And it was EPRI trying to develop a filler metal EPRI P87 for this application.
Check this out:
https://www.epri.com/research/products/000000000001019786

If you mean P No.1 by P1 for A106 I agree that it is not recommended to be joined with Gr.91. A good design will not make such a decision to make these two material meet. It will either make A106 in a wrong service condition (too high temperature) or spend too much money in using Gr.91 where a lower grade could be sufficient.
Parent - - By pradeep4u (*) Date 03-11-2023 19:50
Thanks for your precious information. I will be grateful for that. I have one more doubt that why we use 8018 for p11 and likewise 9018 for p22 because 80 and 90 in code is tensile strength and not base material composition also tensile strength of p11 and p22 material s 60 psi. Also 7018-B2 also has same chemical compostion as 8018-B2 only difference is tensile strenght of welding rod. While 70 ksi is tensile strenght of 7018 and 80 ksi is of 8018. Then how tensile strength different for same chemical compostion. Please enlighten me
Regards
Pradeep
Parent - - By Jovi Zhu (**) Date 03-13-2023 08:09
Hello, if you check ASME SFA-5.5 ( or AWS A-5.5), there are 7018-B2L and 8018-B2. There is actually no "7018-B2". By comparing the chemical compositions of the two classifications, the "B2L" is of identifical composition as that of the B2 except the lower Carbon content which will result in lower tensile strenght. Hope this address the question.
Parent - - By pradeep4u (*) Date 03-14-2023 16:07
Thanks sir,
Please clarify my first part of question that why we use 8018 for p11 and likewise 9018 for p22 because 80 and 90 in code is tensile strength and not base material composition also tensile strength of p11 and p22 material s 60 psi.  Thanks in advance sir for your guidance
Regards
A.Pradeep
Parent - - By Jovi Zhu (**) Date 03-15-2023 11:30 Edited 03-15-2023 11:35
8018-B2 and 9018-B3 are designed to match the chemical composition of base metals, i.e. B2 for P11 and B3 for P22, to produce weld metals for high-temperature service and for matching the properties of the base metals.

Weld metals are not like wrought base metals, they are of "casting" structure in as-welded condition, and even with PWHT they often exhibit higher hardness and strength than that of the matching base metals.
Parent - By pradeep4u (*) Date 03-17-2023 19:42
Thanks sir for your guidance
Regards
A.Pradeep
Up Topic Welding Industry / Technical Discussions / welding of dissimilar metals

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