2 TIG Welding Copper Nickel Alloy Part 2 of 5

The Copper Development Association is pleased to present a series of video presentations covering the welding of the copper-nickel alloy. This video is the second in a series designed to provide welders with the principles of joining 90-10 and 70-30 engineering grades of copper-nickel. Here we consider TIG welding.
To recap, in our first video, we covered preparation for welding.
- Maintain a high level of cleanliness and avoid contamination which can cause weld cracking
- Preheat and post weld heat treatments are unnecessary
We are assuming that all viewing this video are familiar with the basics of welding and our message is to point out where the copper-nickel alloys are different and exceptions are needed.
Direct current electrode negative is the welding current used for TIG welding of copper nickel alloys. The welding power source should have a down-slope or current decay as well as a lift or high frequency start to minimize defects at the start and end of each pass.
The tungsten electrode used for TIG welding copper-nickel can be the same as the one used for welding other alloys such as stainless steel or nickel alloys.
The end of the electrode is beveled by always grinding it in the longitudinal direction. The grinding should be done on a grinding wheel dedicated to tungsten electrodes to prevent contamination.
The filler metal used for welding both the 90-10 and 70-30 alloys is the 70-30 alloy. In making any copper-nickel weld it is good practice to always add filler metal when possible to provide an optimum weld composition.
The shielding gas for gas tungsten arc welding of copper-nickel is 100% argon. The cup size should be as large as practical provided it does not interfere with welder visibility. A gas lens often improves the gas protection and can allow extending the electrode for welding in areas of tight access.
The torch should be held to about a 15º angle back from the direction of travel and filler metal about 90º from the torch or 15º off the work piece. Tilting the torch to a much greater angle tends to reduce the shielding gas protection and the filler metal should always be held within the inert gas shield area. If the filler metal end becomes oxidized, the end should be cut off.
Visually inspect the weld contour and look for defects such as cracks, undercut, or lack of fusion.
In addition to this video presentation there is also free printed literature covering all aspects of fabrication, welding, corrosion resistance and other subjects of help to all involved with the alloys. We invite you to visit www.coppernickel.org or contact [e-mail] to access this literature.

[@BrazilWeldsMessiasCarvalho]

Hello friends!
Very, Very good video. Thank you very much for sharing this wonderful work.
Best Regards from Brazil

[@PauloArturBernardes]

Muito interessante suas aulas.estou aprendendo muito com vcs.Obrigado sr Messias.

[@BrazilWeldsMessiasCarvalho]

Olá ***** ,
Foi uma liga Cobre-Níquel, muito boa essa série vala a pena ver.
Abraço

[@steveroe5974]

I`ve been welding copper nickel for more than 15 Years. I find it amazing there is no penetration in that root pass! why would you need to back grind a flat plate?

[@benfrausto6517]

I'm trying to pass a monel to dh 36 carbon 95ar/5co2 gas any suggestions to eliminate porosity between beads? It only showed up on x-ray not naked eye. Was running about 165 amps. Thanks

[@Mengkomnap]

Hello my sir TIG AC OR DC?

[@SidGinakis]

How about PT after the first pass?

[@baijujoseph340]

dear sir ,
can you suggest which filler wire to be used for welding 90/10 CuNi metal with 2mm thickness, wheather we should go 90/10 cuni filler 1.6mm or 70/10 Cuni filler wire or just Cu filler wire only

[@adamxu-hhpcopper-4738]

Baiju Joseph，I suggest Cu70Ni30

[@forgeanator1716]

what filler rod is used in the joining of 9010 7030 copper nickel pipe with gtaw tig process ?

[@adamxu-hhpcopper-4738]

forge anator，Cu70Ni30 will make it

[@AlphaFlight]

Does it weld similar to silicone bronze?