Filler metal

The filler wire or rod has a grade identical to that of the parent metal.
However, the filler wire or rod used for weld Cu-Ni 90/10 with Cu-Ni 70/30 bare metal available.
Flux coated electrodes can be used for wall thickness of 6mm above.
Cu-Ni 70/30 can be welded with Cu-Ni 70/30 filler metal.
It is important to degrease of parent metal filler metal.

Table 1. is showing national specification of the filler metal.

Edge preparation for butt welded joints

Joint Preparation on pipes ( End beveling to welding) can be used to all types. Generally, edge preparation is the same fig.1.
Welding operation can be carried out under conditions if jointing parts are perfectly clean and free greas, oxidation and dust.
If possible, welding is carried out in down-hand position with "1G"

Internal Protection

To avoid oxidation and fluxing on the inside of the joint, it is required to ensure internal protection by shielding gas (pure 99.9% argon) which is used as the back purging gas (pure 99.9% argon or nitrogen)

Tacking

The parts to be joined together are edge to edge and tacked. The tack weld should be kept to a minimum and as short as possible and should be deposited, cleaned thoroughly before welding commences.
Positional welding is facilities by making the root run by the TIG process. Then, travel is reversed and welding continued with a weave motion.
The diameter of the electrode is individual on the welding current. The following table showing the typical data

The number of pass is necessary to follow table. 2 in order to avoid local overheating which risks causing collapse of the bead.
* Detailed welding procedure specification is available upon request.