Weld overlay of Nozzles and Flanges

[Angsi]

Code: Asme Sect VIII Div 1
Item: A516 Gr 70 + 316Lmm clad, 3mm min.
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The larger nozzles and flanges can be weld overlay deposit clad and then chemically analyzed to confirm the quality of the weld-deposit.

Can a 2" nozzle be successfully cald using the same procedure? I heard that it is quite difficult to weld overlay a 3" let alone a 2" at the vessel fabricator's shop.

For a 2" nozzle should I restrict the source from a clad pipe/fittings manufacturer on the basis that their manufacturing procedures will be more reliable and of quality? Or should I stipulate that all nozzles 2" and below should be solid CRA instead of clad?

Thanks in advance.

 

[johnnymist2003]

Hi,

In my experience, for the smaller nozzles we have always specified them in CRA, if possible.The problem with cladding very small bores is one of phyisical dimensions. Accessibilty for welding is very limited, particularly if the nozzle neck (pipe) is very long.Also, it is dificult to verify the quality of the cladding due to weld dilution etc.If it was me, I'd order the smaller nozzles from CRA, it will reduce problems later, and will probably be cheaper in any case.
Regards.
John

 

[weldtek]

In the Houston area there are several outfits that specialize in weld overlay and routinely do 2" nozzles and smaller.

 

[picasa]

What does CRA stand for?

 

[weldtek]

I assumed corrosion resistant alloy?

 

[Angsi]

Yes it stands for Corosion Resistant Alloy. I have speaking to local vessel fabricators here at the same time and learnt that though they claim that their weld overlay machines are capacble of nozzle sizes 2", they are bit hesistant when I mentioned that chemical analysis is required to verify ferrite content at the fusion line. They change their mind and prefer to use solid CRAs for smaller nozzle.