Copper-Nickel Filler for GTAW, 90-10??

[Capntom]

We are welding schedule 80 pipe. Alloy is 90-10 Copper Nickel. Commercial application. We have used Monel wire in the past. We were just told that the Monel is not the alloy of choice, lol. What alloy should I be using that is available for GTAW, Ø 1/16???

 

[metengr]

Recommended filler metal for 90/10 Cu-Ni alloy using the GTAW process is as follows;

SFA 5.7
ERCuNi UNS C71580

I believe you can also purchase bare wire from Europe that closely matches the 90/10 Cu-Ni alloy;

SG CuNi10Fe

 

[sayee1]

I have successfully welded cupronickel(90:10) with matching consumables. However, there are two reasons put forward for using 70/30 as the weldmetal for the material. The first is that considerable coring can occur in the 90/10 weldmetal thus giving denuded regions which corrode preferentially. The second is that the specification for the parent and weldmetal for 90/10 is the same. Therefore you may get parent with max nickel and weldmetal with min nickel making the weldmetal anodic. To overcome both potential problems CuNi 70/30 weldmetal is used. SFA 5.7, ERCuNi is CuNi 70/30



Thanks and regards
Sayee Prasad R CEng MWeldI MIOMMM


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