Weld Strength Reduction Factor 1

[PhilEduard]

All,

Power piping does not consider weld srength reduction factor W (Wc in Caesar II) but process pipng does and B31.3 addresses a situation where at temp. more than 1500 deg F., W should be obtain by the Designers themselves. Does anyone knows where this figure would come normally?

Thanks Guys,

Phil

 

[davefitz]

Normally, if you were working for a large boiler company or large piping fabricator, your company would have staff metalurgists and access to a modern metallurgical lab. You would review published conference proceedings of other researchers who have published results of long term creep testing of welds that are similar to the type of weld you are considering for your vessel. Then the same test would be confirmed by tests in you company's lab, if time permits.

If the asme has not provided official weld creep strength reduction factors for the alloy and thickness under consideration, then you will need to ensure adequate safety of the weld for the obvious purposes of safety of plant workers, equipment availabilty,and personal and corporate liability purposes. This means you would have to document all credible prudent measures that have been taken to ensure that a normal service life is to be expected with the weld. In my opinion, it would be prudent to also specificy the use of creep monitoring devices or procedures, and more QC trests during fab than for standard butt welds.

Some sources for published tests of weld creep strength reduction factors have been found in the proceedings of the ASME PVP conferences, and the online tech journal <www. ommi.co.uk>

 

[PhilEduard]

Hi Davefitz,

Thank you so much for your tip and information. I really do appreciate your time on this.

Regards,

Phil