Multiport nozzle a constricting nozzle of the plasma

Multiport nozzle . A constricting nozzle of the plasma arc torch containing two or more orifices locat-
ed in a configuration to achieve some control over the arc shape. See Mig welding.
N
Narrow groove welding . A variation of a welding process using multiple-pass welding with filler met-
al. The use of a small root opening, with either a square groove or a V-groove and a small groove
angle, yields a weld with a high ratio of depth to width.
Neutral flame . An oxyfuel gas flame that is neither oxidizing nor reducing. See carburizing flame,
oxidizing flame, and reducing flame. Neutral flux. A flux formulated to produce a weld metal composi-
tion that is not dependent on the welding parameters, especially arc voltage ( submerged arc welding) .
See active flux and alloy flux.
Non-butting member . A joint member free to move in any direction perpendicular to its thickness
dimension. For example, both members of a lap joint, or one member of a T-joint and corner joint.
Non-consumable electrode . An electrode without filler metal. See TIG Welding (GTAW).

PDHonline Course M564
©2015 Jurandir Primo Page 55 of 121
Noncorrosive flux . A flux in either its original or residual form that does not chemically attack the
base metal ( brazing and soldering) .
Nondestructive Examination (NDE) . The act of determining the suitability of a material or a compo-
nent for its intended purpose using techniques not affecting its serviceability.
Non-Vacuum Electron Beam Welding (EBW-NV) . An electron beam welding process variation in
which welding is accomplished at atmospheric pressure.
Nozzle . A device at the exit end of the gun that directs the atomizing air or other gas ( arc spraying,
flame spraying . A device at the exit end of the gun that directs and forms the flow shape of atomized
spray particles and the accompanying air or other gases. Nozzle accumulation. Filler metal or surfac-
ing material deposited on the inner surface and on the exit end of the nozzle.
Nugget . The weld metal zone in a spot, seam, or projection weld. Nugget size. A nonstandard term
used for projection weld size, resistance weld size, or seam weld size.
O
Oil-bath dip soldering . A dip soldering variation using heat from a bath of heated oil. See metal-bath
dip soldering and salt-bath dip soldering.
Open butt joint . A nonstandard term when used for a butt joint with a root opening and with no back-
ing. See open root joint. Open root joint. An unwelded joint without backing or consumable insert.
Open circuit voltage. The voltage between the output terminals of power source when the rated pri-
mary voltage is applied and no current is flowing in the secondary circuit.
Orifice gas . The gas directed into the plasma arc torch or thermal spraying gun to surround the elec-
trode. It becomes ionized in the arc to form the arc plasma and issues from the constricting orifice of
the nozzle as a plasma jet. Orifice throat length. The length of the constricting orifice in the plasma arc
torch or thermal spraying gun.