Hello Carpediem,
Ni & Cu have unlimited solid solution
properties, that's why it's easy to formulate Monel or Cupro Nickel
electrodes.In fact these electrodes are just flip sides of each other, example
Monel 400- 70Ni-30 Cu, Cupro Nickel-70/30-- 70 Copper 30
Nickel.
The nickel-copper and copper-nickel welding
products (MONEL Welding Electrodes 190 and
187, MONEL Filler Metals 60 and 67) can
tolerate unlimited dilution by
copper.
Depending on the service
and the corrosive environment you have the
flexibility of using either Cupro Nickel or Monel electrodes. Cupro Nickel is
cheaper and have lesser mechanical properties and relative lesser corrosion
resistance that Monel.
If the intended service is for sea-water corrosion, e.g marine or desalination environment
Cupro Nickel fillers (i.e Monel -67 or SMAW-Monel-187 ) would be the
choice.
If the intended service is corrosive process environment or any application of NACE sour
service then Monel 60 filler and matching SMAW electrode Monel -190
would be a better choice.
Please find the
electrode selection guide of Special Metals Corp for further
guidance.
Thanks.
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
& Consultant
Ontario,Canada.