©
COPYRIGHT 2000 THE ESAB GROUP, INC. LESSON
IX tion by the GMAW process and
FCAW process semi-automatically. In both processes the welding
current and voltage must be lowered to weld out-of-position, and in GMAW, the
short circuiting arc transfer must be used.
Example 3 compares the weld metal cost per pound deposited
by these processes, using the proper current and voltage for depositing a ¼”
fillet weld on ¼” plate, vertically
up. Note: The cost
of electrical power is comparable in all processes and therefore, can be eliminated
as a factor. 9.6.1
Example 3
FCAW
GMAW
Electrode Type - .045”
dia. E71T-1 .045” dia. ER70S-3
Labor & Overhead - $30.00/hr
$30.00/hr Welding
Current - 180 amperes 125
amperes Deposition Rate -
4.9 lbs/hr (Fig. 9) 2.8
lbs/hr (Fig. 10) Operating Factor -
45% (Fig. 2) 50%
(Fig. 2) Electrode Cost -
$1.44/lb $.66/lb
Deposition Efficiency - 85%
(Fig. 9) 96% (Fig. 6) Gas
Flow Rate - 35 cfh (Fig. 7)
35 cfh (Fig. 7) Gas
Cost Per Cu. Ft. - $.03 CO2
$.11 75% Ar/25% CO2
This data is tabulated in the chart in Figure 17.
9.6.1.1 As you
can see, the cost of depositing the weld metal is about 33% less using the
Flux Cored Arc Welding process. Since there is
no slag to help hold the vertical weld puddle in
the GMAW process, the welding current with solid wire must be lowered considerably.
This, of course, lowers the deposition
rate, and since labor and overhead is the largest factor in- volved,
it substantially raises deposition costs. In the flat or horizontal position,
where the welding current on the solid
wire would be much higher, the cost difference would be consider-
ably less pronounced.
