Dissimilar metal welding 3

[Ankur15061992]

While welding cladded pipe, where single side approach is only possible (Monel clad pipes on CS),Which is better to use Pure Nickel or pure iron electrode?
Please give the reasons also. Pipe is not operating in creep range (Just 160 degree C design).
ESAB E-Ni-1 (Pure Nickel) is used for buffer layer for surfacing and Armco is pure iron electrode.
As environment is Chloride containing so we cant use SS electrodes.

 

Retain a Welding Engineer.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[mfgenggear]

ironic metallurgist (Materials)30 May 21 00:16
Retain a Welding Engineer.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

X1

 

[weldstan]

Ditto ironic metallurgist. Think about corrosion resistnce of unknown iron-coppper-nickel alloy adjacent to monel cladding. Neither of your proposed fillers may be appropriate.

 

[Ankur15061992]

What i mean was for welding, i will use 2 layers of monel upto Cladding thickness and then buffer layer of pure Nickel and then finally weld with CS electrodes.
I think it is standard practice. Why u r just telling philosophy suggest solution.
We already did PQR of this and it works nice

 

[Ankur15061992]

Pure Ni can dissolve upto 50% ferrite in it before cracking and hence can be used as buffer layer.
Pure iron however cant be used as monel cant dissolve more than 15 percent iron.
Any comments on this

 

I have seen career welding engineers mess up back cladding when doing it from the clad side (the easy side).
You especially don't want to mess up with Monel, which is used for some of the nastiest environments, including hydrofluoric acid.
Demand that your WE consultant describe the measures he/she will prescribe to keep dilution down to an acceptable minimum on the process facing side. Actually, first determine what that minimum dilution should be for your process fluid and temperature.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[mfgenggear]

I have seen career welding engineers mess up back cladding when doing it from the clad side (the easy side).
You especially don't want to mess up with Monel, which is used for some of the nastiest environments, including hydrofluoric acid.
Demand that your WE consultant describe the measures he/she will prescribe to keep dilution down to an acceptable minimum on the process facing side. Actually, first determine what that minimum dilution should be for your process fluid and temperature.

man there are so many safety issues with this, and environmental impact issue, I would not experiment with these welds, I would even consult two welding engineers.

 

[weldstan]

While the welder, who successfully made your PQR is qalso qualified to make production welds, how will it translate to field welding conditions with other welders or is all this welding done in a shop where welders can readily be qualified and monitored?