ERCuNi (NA67) is used for gas metal and gas tungsten arc welding. Can also be used by oxy-fuel welding of 70/30,80/20, and 90/10 copper nickel alloys. A barrier layer of nickel alloy 610 is recommended prior to overlaying steel with GMAW weld process. Note: Other shielding Gases may be used for Tig welding. They are the materials of first choice for seawater pipework and condenser/heat exchanger service