Electrode 80S-B8 for GTAW & El 3

[SrinivasJS]

Electrode 80S-B8 for GTAW & Electrode 8018-B8 for SMAW. to be used FOR WELDING A335 P9 PIPE MATERIAL.
Electrode 80S-B6 for GTAW & Electrode 8018-B6 for SMAW- used elecrode.

We have done welding & installed in site “A335 Grade 9 pipe material” with existing WPS with above electrode B6.
This happened because all Parameters like P No.,F No. & A no. are matching with existing WPS & Mechanical properties Strength (60 KSI, Minimum) is also matching.
Only slight difference in chromium & Molebdenum Electrode

What is the solution for this?

 

[weldstan]

B6 is a 5Cr filler metal. A matching 9Cr filler metal should be used. P9 is normally used for high temp sulfur containing or hydrogen containing fluids. The 5Cr filler will corrode or stress crack much faster in those environments.

 

[SrinivasJS]

What is the solution we have to cut and reweld all 750" diameter pipe ?

 

[metengr]

That is one of two options - re-work and use the correct filler metal OR monitor.

 

[SrinivasJS]

If Pipe line(P9 MATERIAL ) connecting to Tie in is P5 material than any excuse for cut and welding ,MONITOR means what ,can you detail it ?

ASME SEC 9 Table QW-442 Says A5 material chrome 4% -10.5%(classification of ferrous weld metal analysis for procedure qualification),can we consider this for acceptance of PMI results.

 

[metengr]

Monitor means you develop an inspection program for targeted welds containing the 5% Cr filler metal. The inspection program as part of your nonconformance resolution is to perform nondestructive testing every 2 years or agreed upon interval to check for cracks, period.

 

[weldstan]

A No is only applicable regarding procedure qualification in your case. It is not germane to the issue of using mismatched filler metal to the base metals joined. You should be asking the Owner/Owner's Engineer for guidance as to what to do. If I were the Owner, and service dictated the need for the B8 filler, I would have you cut the welds out and replace them with the B8 filler, especially when failure would lead to catastrophe.

 

[NBrink]

Yeah, ask whoever specified 9 Cr for the line if 5 cr welds will be a problem. I don't have a lot of faith that such a special inspection program as monitoring all the welds on a new circuit will be maintained properly.

If it were my piping, I'd have every weld cut out and personally run off whoever tried to weasel their way out by claiming the A number limits as PMI limits. That's just me though...

Nathan Brink

 

[SrinivasJS]

Other than cutting is there any option ?please needed suggestion

 

[metengr]

Yes, you either monitor or cut them out and re-weld. Those are your only two options.