Dissimilar Metal Joining and Weld Overlaying on Copper Nickel Alloys
(120 votes)Suggested filler metal for joining Cu-Ni alloys to some of the commonly combined other alloys is shown in Table 6. The listing is not intended to be exclusive in that welding procedures could be developed using filler metals not listed.
| Table 6 Filler Metals for Dissimilar Metal Welds | |||
| Metal to be joined to Cu-Ni |
SMAW (UNS) | GMAW and GTAW (UNS) | Comments |
| ANSW/AWS A5.6 | ANSI/AWS 5.7 | ||
| Copper | ECuNi (W60715) or ECuA1-A2 (W60614) |
ERCuA1-A2 (71580) or ERCuA1-A2 (C61800) |
Preheat to 1000°F (540°C) |
| Phosphor bronzes | ECuSn-A (W60518) | ERCuSn-A (C51800) | - |
| All bronzes | ECuA1-A2 (W60614) | ERCuNl (C61800) | - |
| ANSI/AWS a5.11 | ANSI/AWS A5.14 | ||
| Carbon steel | ENiCu-6 (W84190) | ERNiCu-7 (N04060) | Steel side may be overlayed first with ERNi-1 or ERNiCu-7 |
| Austinetic stainless steels | ENi-1 (W82141) or ENiCrFe-2 (W86133) |
ERNi-1 (N02161) or ERNiCr-3 (N06082) |
Stainless side may be overlayed first with ERNi-1 |
The 70-30 Cu-Ni welds have a limited tolerance for dilution by iron. Welds with more than about 10% iron tend to have excessive fissures and develop hot cracks. The ENiCu-7 and ERNiCu-7 fillers (65Ni-Cu) have a higher tolerance for iron and are used in joining to carbon steels. However, they are not a good choice in welding to stainless steels because of limited tolerance for dilution by chromium.
Often a very useful step in making Cu-Ni dissimilar metal welds is to overlay or butter the other metal with nickel, nickel-copper or any other appropriate filler shown in Table 6. In applying Cu-Ni overlays on steel, the usual practice is to apply a first layer with ERNi-1 or ERNiCu-7 and then ERCuNi for subsequent layers. Although a high alloy barrier layer is standard, it is possible to apply ERCuNi by GMAW directly on carbon steel with carefully controlled welding procedures designed to achieve relatively low iron dilution on the first layer.
The submerged arc welding (SAW) process is ideally suited for overlaying large surface areas. Commercial submerged arc fluxes are available for all the nickel, nickel-copper and Cu-Ni filler metals.(3) In overlaying carbon steel, the first layer is applied using either an ERNi-1 or ERNiCu-7 filler metal followed by subsequent layers of ERCuNi to reach the needed thickness or composition.
Brazing with BAg-1a, BAg-1 and BAg-2 is suitable for joining Cu-Ni to any other copper alloy.
by Richard E. Avery
Article about welding, soldering and brazing of copper nickel alloys (cupronickel). This describes SMAW, GTAW and resistance welding, similar and dissimilar welding ,
http://www.copper.org/applications/cuni/txt_joining_CN_alloys.html
Copper and Nickel Alloy Welding Materials
Weld electrodes developed to join and overlay nickel, copper, bronze and many dissimilar ferrous and non-ferrous alloys for welding cast iron and joining cast iron to
http://www.weldmold.com/index.php?option=com_content&view=article&id=128&Itemid=10
Joining of Copper and Copper Alloys
Joining of Copper and Copper Alloys. CDA Publication No 98. September Copper-nickel alloys. Not difficult to solder if clean and well fluxed but soldering is
http://www.copperinfo.co.uk/design-and-manufacture/downloads/pub-98-joining-of-cu-and-cu-alloys.pdf
Handbook – Copper Alloys
When joining brass and bronze, All-State® No. 21 Flux should be used. No. 21 will join copper-nickel alloys with less than 30% nickel; not recommended for ferrous metals.
http://www.esabna.com/EUWeb/AS_handbook/596as6_4.htm
Copper-Nickel Alloys, Properties and Applications
Table 8 – Suitability of joining processes for copper-nickel alloys The Joining of Copper and Copper Alloys, CDA Technical Note TN25, 1980.
http://www.copperinfo.co.uk/alloys/copper-nickel/downloads/pub-30-cu-nickel-alloys.pdf
Joining
some of the characteristics of nickel alloys necessi- tate the use of joining nickel alloys in thicknesses from 0.1 to 0.3 in. Thicknesses outside that range
http://www.specialmetalswelding.com/publica/joining.pdf
Copper.org: Copper Nickel : properties, processing and
German Copper Institute (DKI) Overview of copper nickel (cupronickel) composions, standards, properties, manufacture, fabrication joining and applications
http://www.copper.org/applications/cuni/txt_DKI.html
