Temper bead welding and carbon equivalent

[numberfive]

Experts,

I am in the process of qualifying a temper bead welding procedure in accordance with Section IX QW-290 for P5A material.

One of the essential variables (QW-403.26) is an increase in the carbon equivalent of the base material using the equation: CE = C + (Mn/6) + (Cr + Mo + V / 5) + (Ni + Cu / 15).

The base material for my PQR is SA-387 Gr. P22. Section II Part A does not require Cu, Ni, and V to be reported on the MTR.

Without knowing the percentage of these three elements in my base material is it safe to enter values of zero in my CE calculation or should I have further analysis done to determine these levels?

I'm not a metalurgist but I'm assuming that if ASME does not require these elements to be reported, they must have little effect on the mechanical properties of the material at the levels found in common steel manufacturing practices?

To push this a little further, no MTR's are available for the base material that we will be using this procedure on in the field (repair work on an existing header) and even if they were Cu, Ni, and V would most likely not be found on them.

Any insight would be greatly appreciated.
numberfive

 

[metengr]

First, you should have an MTR for the plate. So, how do you know if the material is Grade 22 just because it has markings on it? The cost of a chemical analysis is less than $200 USD and would provide the necessary documentation.

 

[numberfive]

metengr,

I do have an MTR for the plate that we will be using for the PQR - no Cu, Ni, or V values supplied.

The plate was clearly marked upon receipt with all of the Section II required markings traceable to the manufacturer's test report.

I am fully confident that the material for the PQR is Grade 22.

It sounds like you feel that a chemical analysis to provide the actual Cu, Ni, and V values is the best way (only way) to proceed to accurately calculate CE.

That being the case I will also need an analysis of the header material to calculate it's CE and verify that it does not exceed that of my PQR to ensure compliance with QW-403.26.

numberfive

 

[metengr]

numberfive;
Ok, the additional information helps. If you have the MTR for the plate, you are good to go. Just use 0 for the tramp elements if they were not reported. For the header material, you can use the material specification maximum ranges for CE (this would be conservative) or run an analysis.

 

[numberfive]

metengr,

Thank you for the guidance.

numberfive