Welding Carbon Steel Root With FAC Requirements!

[iam42]

Hi Guys,

We have a project in-house that requires all material to be resistant to Flow Accelerated Corrosion. The material to be used is A106B for the pipe and A105 for the flanges.

The requirement that has been stipulated is that all material including weld wire must have a minimum chromium equivalent of 0.16.

This is calculated as; CrEq = Cr + 0.19Mo + 0.4Cu.

My problem is that I cannot find any ER70S wire that meets the required chemistry.

At the moment I am thinking about overlaying the ID at the weld root area with Stainless Steel but this is not ideal as the root needs to be ground flush after welding.

I was wondering if anyone knows of a better solution or knows where I may find wire that will meet these requirements.

Or is there any reason why I should not fully weld this joint with a ER309 stainless steel?

Many Thanks

 

[EdStainless]

You can't find 1/4% Cr weld filler that meets this?
That is what I have seen used.

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

 

[iam42]

Hi Ed,

Thanks for the suggestion, I cannot find anything online for 1/4 Cr filler.

Did you mean 1-1/4 Cr?

I can find plenty 1-1/4 Cr but that has an A-number of 3 which would not work for my qualified WPS (A-Number 1).

Thanks again.

 

[metengr]

Qualify a welding procedure using 1.25%Cr - 1/2%Mo filler metal for FAC resistance on carbon steel.

 

[iam42]

Metengr,

Your suggestion would probably be the most straightforward approach but I do have one question!

I already have a qualified PQR for P4 material welded with ER80-B2. This PQR was carried out with no PWHT and is qualified up to 5/8" thick

Can I write a new WPS based on this PQR for welding P1 to P1 material using ER80-B2 based on [highlight #FCAF3E]ASME IX. QW-403.12[/highlight]

QW-403.12 A change from a base metal listed under
one P‐Number of Table QW/QB-422 to a base metal listed
under another P‐Number. When joints are made between
two base metals that have different P‐Numbers, requalification
is required even though the two base metals have
been independently qualified using the same procedure.
[highlight #FCE94F]When the melt‐in technique is used for joining P‐No. 1,
P‐No. 3, P‐No. 4, and P‐No. 5A, a procedure qualification
test with one P‐Number metal shall also qualify for that
P‐Number metal welded to each of the lower P‐Number
metals, but not vice versa.[/highlight]

I would appreciate you thoughts on this.

Ian

 

[metengr]

It would be P-No 4 to P-No 1 and not P-No 1 to P-No 1.

 

[weldstan]

You can purchase metal cored GTAW wire from Devasco meeting the requirements. We have been welding SA-106 C form a Mill in Japan having the appropriate CrEq for years with the Devasco filler metal.

Because of the limited availability of the SA-106 C material, many companies simply specify 1 1/4 Cr -1/2 Mo alloy for pipe subject to FAC.

 

[iam42]

Thanks Weldstan,

I will give them a try.

Much appreciated.