CEMP-E
TI 809-26
1 March 2000
c. Advantages, Disadvantages and Limitations. The Flux Cored Arc Welding (FCAW) process offers
several advantages over Shielded Metal Arc Welding (SMAW), but also has a few disadvantages and
limitations
(1) The FCAW electrode is continuous, eliminating the numerous starts and stops necessary with
SMAW on longer and larger welds.
(2) Increased deposition rates are possible with FCAW because the current can be higher than with
electrode is passed through a contact tip usually 20 to 25 mm (3/4 to 1 in.) from the end of the electrode,
minimizing the buildup of heat from electrical resistance. This electrode extension distance, commonly
called "stickout," varies for each WPS, and may be considerably higher. Both factors provide FCAW an
economic advantage over SMAW.
(3) The number of arc starts and stops, a potential source of weld discontinuities, is also reduced.
(4) The equipment required for FCAW is more expensive and complicated than SMAW, and more
difficult to maintain. This increased cost is offset by the higher productivity levels achieved using FCAW
compared to SMAW.
(5) FCAW electrode wires do not need heated holding ovens for ordinary applications, but caution
should be used when FCAW wires are exposed to the elements for extended periods of time. For critical
welds requiring very low hydrogen deposits, more restrictive storage requirements may be warranted.
(6) FCAW is capable of all-position welding when using small diameter electrodes. Large diameter
electrodes, using higher electrical currents, are restricted to the flat and horizontal positions.
(7) There are several advantages to using FCAW-S (self-shielded) rather than FCAW-G (gas-
shielded). The FCAW-S welding gun assembly does not require a gas nozzle, also called a gas cup,
therefore access into smaller areas is possible, significant when welding in tight locations such as weld
access holes in beam-to-column connections. The welder is also better able to see the arc and weld
puddle because the gas cup is not present.
(8) A second advantage to FCAW-S over FCAW-G is its ability to make quality welds under field
conditions involving wind. For FCAW-G, it is necessary to erect protective shielding from wind to
maintain the shielding gas around the molten weld puddle. Such shielding may be expensive, time-
consuming, require additional ventilation for the welder, and constitute a fire hazard. FCAW-S eliminates
the handling of high pressure gas cylinders, theft of cylinders, protection of gas distribution hosing under
field conditions, and the cost of the shielding gas. For shop fabrication, wind is less of a problem than
under field conditions. However, drafts from doorways and windows, fans used to cool personnel and
provide ventilation, and welding fume exhaust equipment can create unacceptable wind speeds that
degrade weld quality.
(9) FCAW-G "operator appeal" is usually higher than with FCAW-S because of better arc control
and less fume generation. FCAW-G is less sensitive to variations in electrode extension and arc voltage
than FCAW-S. The range of suitable applications for a single size and classification of FCAW-G
electrodes is generally broader than for FCAW-S electrodes.
(10) FCAW-S procedures must be closely controlled to ensure the required level of weld quality
and mechanical properties. Because of the high deposition rates possible, travel speeds and technique
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