©
COPYRIGHT 2000 THE ESAB GROUP, INC. LESSON
IX 9.4 COST
CALCULATIONS - EXAMPLE 1 9.4.1
Calculating the Cost Per Pound of
Deposited Weld Metal 9.4.1.1
Example 1 - Calculate the cost of welding
1,280 ft. of a single bevel butt joint as shown
in Figure 14 using the following data. a.
Electrode - 3/16” diameter, 14” long, E7018, operated at 25 volts,
250 amps. b. Stub
Loss - 2 inches c.
Labor and Overhead - $30.00/hr d.
Electrode Cost - $.57/lb e.
Power Cost - $.045/kWh 9.4.1.2
The formulas for the calculations are
shown on the Weld Metal Cost Worksheet in Figure
12. The following explains each step in the calculations.
Line
1- Labor and Overhead - $30.00/hr (given)
Deposition Rate - From shielded metal
arc welding deposition data chart in Figure
9 = 5.36 lbs/hr. Operating
Factor - Since it is not stated above, use an average value of 30% (.30)
shown in Figure 2.
The cost of labor and overhead per
pound of deposited weld metal can now be calculated
as $18.66/lb. Line
2 - Electrode Cost Per Pound - $.57 (given)
Deposition Efficiency - From the shielded
metal arc welding deposition table in Figure
9 = 74.6%. Since this is a coated electrode, the efficiency must be adjusted
for stub loss by the formula following
Figure 3. We know that the electrode length is 14"
and the stub loss is 2" (given). The formula becomes:
Efficiency - Stub Loss = (14-2)
x .746 ÷ 14
= .639 or 63.9% 63.9%
is the adjusted efficiency to be used in Line 2. The
cost of the electrode per pound of deposited weld metal can now be calculated
as $.89/lb. Line
3 - Not applicable for coated electrodes.
Line 4 - Not
applicable for coated electrodes.
