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Estimation and Comparison of Welding Cost of MIG & MAG Process on Mild
Steel
Article · January 2011
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Proceedings of the National Conference on “RECENT ADVANCES IN MANUFACTURING ENGINEERING & TECHNOLOGY”
January 10-11, 2011
Estimation and Comparison of Welding Cost of MIG & MAG Process on
Mild Steel
Sunil Kumar1
Sachchida Nand2
1
2
AP
PG Student
Department of Mechanical Engineering
Sant Longowal Institute of Engineering & Technology
Longowal, Sangrur, – 148106
Punjab India
Email: sunil_thappa@yahoo.com
Abstract
In the present work welding cost estimation was done. Welding cost estimation was done for MIG &
MAG and the cost difference has been investigated by calculating for both the cases (MIG & MAG)
for welding the piece of MILD STEEL (contains carbon 0.15 to 0.3 %, silicon 0.2 to 0.5 %,
manganese, sulphur and phosphorous as impurities). The calculation was done by Parameter method
and cost difference found was approximately Rs. 20 calculated for the mild steel pieces (150*15*80)
mm having butt welding with the V-groove (45 Degree). By market survey it was observed that in a
small scale industry total length welded per day is approximately 100 meter. If MAG is used instead
of MIG for the process where the properties required are satisfactory (by MAG welding) than one can
make more profit. The present work was done to generate data for MIG & MAG process.
Keywords: MIG, MAG, Cost estimation, Parameter method
-
1. Introduction:
In the present scenario Welding-cost estimate is
one of the most important tools for the economic
conduction of a welding enterprise and other
production enterprise. It is almost incredible that
in this epoch of global competition and of
almost daily survival struggle with the color of
the bottom line. The setting up of a reliable
system concerning the estimation of costs, takes
a considerable importance for the manufacturing
enterprises
working
on
request.
The
manufacturing cost is generally obtained by the
produce of a part manufacturing time and the
manufacturing time estimation methods namely.
The analytic method: It allows evaluating
a product manufacturing time thanks to the
decomposition
of
an
elementary
manufacturing operation set. We define, for
each operation, the necessary time from
which we can calculate the manufacturing
cost: “manufacturing time multiplied by the
manufacturing hourly cost “.
- The parameter method: which is based
on the utilization of mathematical relations
founded on the information’s gathered by
the enterprise so as to be able to determine
if there exist the correlations between the
different times and the manufacturing
operations.
The analogue method: It is based on the
classification and the indexes of the
products to manufacture by the enterprise
according to morphs-dimensional criteria
and to quality. The new product cost is
estimated by comparison with reference to
the last newly indexed products.
Fig-1 Model perposed for the welding cost
estimation
The analytic method consists in describing and
developing the whole of operations necessary
for the production of the product, this method is
known for its accuracy and by its slowness as
well. To replace the analytic approach, many
enterprises move towards the analogue and the
parameter methods. These methods are
relatively rapid, it is because they are essentially
55
Proceedings of the National Conference on “RECENT ADVANCES IN MANUFACTURING ENGINEERING & TECHNOLOGY”
January 10-11, 2011
synthetic and function in total darkness. They
provide the product cost according to certain
characteristics which limit the negotiating
transparency of marketing men. In this study
further estimation was done as per parameter
methods.
2.2. Preparation cost:
The cost of cutting to dimension each single
piece of metal, the job was properly accounted
for and summed to the total. Set up preparation,
alignment and measuring of gaps and distances
are recurring operations: the implementation of
wisely conceived fixtures and measuring aids.
Specimen Angle
Machine
Time
Cost
PreparaTaken
tion
V450
Shaper
10mins Rs.
Groove
M/C
each
70/Specimen 3-Small Grinding
15mins Rs.
15mm
Cutters
Cutter
each
90/Specimen 2-Small Grinding
8mins
Rs.
6mm
Cutters
Cutter
each
60/Table 2: - Cost estimation of preparation
Total Specimen Preparation Cost: Rs. 220/-
2. Welding-cost estimate:
Cost estimation of welding process was done by
estimating the cost of each steps involved in
welding. So total welding cost was sub divided.
i.e. Total Welding Cost:
1. Base metal cost
2. Preparation cost
3. Weld Labor cost
4. Filler Metal cost
5. Gases cost
6. Equipment cost
7. Energy cost
8. Overhead cost
9. Inspecting cost
10. Finishing cost
2.3. Labor Welding-cost:
Weld labor is usually accounted for as an hourly
rate, which will be different for different welders
depending on their experience, skill, ability,
versatility etc. Operator or operating factor
describes the percentage of time that a welder
employs in actual welding. Operating factor
values commonly accepted in the welding
industry range from 30 to 50%. This is one of
the reasons most commonly reported for
management push to switch. Good practice
suggests striving for obtaining good quality at
the first attempt, in order to minimize
unnecessary operations like repair, rework and
re-inspect, which increase the costs without
providing any gain or advantage in the business.
(Material Cutting + Cleaning + Machining) =
Cost Included with Other Costs. It is necessary
to estimate the time required for welding a
specific demand. Its helps in calculating labor
charges.
Welding Time = (Weight/ft. of Weld x ft. of
Weld) ÷ (Deposition Rate x Operating Factor)
2.1. Base metal cost:
This is the cost incurred for procuring (including
custom dues), transporting, insuring, and
handling, storing, testing and bringing all the
material in the proper sequence, quality and
quantity at the place of erection, ready to be
prepared for welding.
No. Material Carbon Silicon Mangnese
(Thick)
+Sulphur
1
Mild
0.15% 0.2% As
Steel
- 0.5%
0.5%
impurities
(15mm)
2
Mild
0.15% 0.2% As
Steel
- 0.5%
0.5%
impurities
(6mm)
Table 1: - Composition of the weldment
Base-Metal Cost: Rs 480/-
Welding Labor Cost: Rs 50/2.4. Filler metal cost:
Working with the correct size of filler metal has
a direct influence upon the Welding-cost. A
smaller size of electrode permits to increase
current density, which may have influence upon
penetration. A larger size permits working with
higher current, with consequent higher volume
of metal deposited per unit time. Deposition
efficiency is defined as the ratio, expressed in
Fig-2 Specifications of weldment
56
Proceedings of the National Conference on “RECENT ADVANCES IN MANUFACTURING ENGINEERING & TECHNOLOGY”
January 10-11, 2011
(Or)
Deposition Rate (lbs/hr) ÷ Burn-off Rate (lbs/hr)
= 0.33/0.36 = 91.66 % (15mm)
= 0.15/0.16 = 93.57 % (6mm)
Filler Metal Cost = Filler metal cost per kg /
Deposition efficiency
=4.48 kg /0.916 = Rs 4.10/=4.48 kg /0.935 = Rs 4.18/-
percentage, of the theoretical weight (volume
multiplied by density) of the joint material
needed per unit length, to the actual weight of
filler metal consumed per unit length. This can
be best calculated from raw data or assumed if
based on previous experience. If we know the
weight of filler metal necessary to weld one unit
of length (meter or foot) of that given joint and
if we know the number of unit lengths welded in
one hour, by multiplying the two we get the
weight of filler metal used per hour. This is
called the Weld Deposition Rate; by multiplying
this result by the cost of filler metal per unit
weight we get the Welding-cost of filler metal
Consume in an hour.
Electrode/Filler Metal Used:
AWS: SFA-5.18, ER-70S-6, Grade – S4.
0.8mm Diameter Bare Wire
Carbon
Manganese
Silicon
0.060.14
1.3-1.6
0.7-1.0
2.5. Gases cost:
This cost intervenes only when auxiliary gases
are actually used in the process. In this case the
cost of gas per hour (including welding and nonwelding time when flow is zero) is obtained by
the hourly consumption rate.
Gases Used:
- CO2.
- (98%) Argon + (2%) Oxygen Mixture.
CO2 Cylinder Cost (Large) = Rs. 725/Argon Cylinder Cost (Large) = Rs. 1250/Oxygen Cylinder (Large) = Rs. 925/Since the amount of gas used is too low. Thus,
Gas Cost: Gas cost is near about 2% of total cost
i.e. Rs. 15/- for MAG and Rs. 35/-
Sulphur +
Phosphorus
<0.050
Table 3:- Composition of electrode
Diameter
Current
Ø 0.8
50-70
Amps
Ø 1.0
80230
Amps
Ø 1.2
120280
Amps
Ø1.6
200400
Amps
2.6. Equipment Welding-cost:
The easiest way to account for equipment is to
record the rental cost, if the equipment is indeed
rented. Otherwise the Accounting department
should come up with a cost per hour or per day
for each of the main pieces of equipment,
including purchasing cost, cost of capital,
depreciation, maintenance costs and spare parts
costs.
Equipment Cost: Negligible due to low range
near about Rs. 3/-.
Feed
2.5Rate
2.5-10
3-10
3-8
12
(m/min)
Voltage
15-20 Volts
25-30 Volts
Range
(6mm Plates)
(15mm Plates)
Table 4: - Specification of electrode
Current Selected:
 Specimen (15mm) = Final Wt. –Initial
Wt. = (3.02 – 2.69) kg = 0.33 kg
 Specimen (6mm) = Final Wt. –Initial
Wt. = (1.57 – 1.42) kg = 0.15 kg
Wire Feed Rate Selected:
 8mm/min (Kept same for all thickness)
Length of Wire Used:
 1.48m (15mm) 0.36kg
 0.95m (6mm) 0.16kg
Weight of Weld Metal:
 Specimen (15mm) = Final Wt. –Initial
Wt. = (3.02 – 2.69) kg = 0.33 kg
 Specimen (6mm) = Final Wt. –Initial
Wt. = (1.57 – 1.42) kg = 0.15 kg
2.7.
Energy cost:
For electric equipment the Welding-cost
estimate should be calculated by multiplying
Voltage by Amperage and dividing by 1000 and
by the electric efficiency of the equipment, times
the price per kW.hr (kilo Watt hour) time the
operating factor (actual arc-on time per hour). In
case of a gasoline engine driven power
generator, the hourly energy cost would be that
of the gasoline used up in an hour of normal
work. When using electrically heated furnaces or
other implements for preheating or post heating,
the cost of energy used for heating should be
estimated and accounted for.
Power/Energy Cost= (COST/kWh x VOLTS x
AMPS) / (1000 x DEPOSITION RATE)
Deposition efficiency =
Weight of Weld
Metal (kg) ÷ Weight of Electrode (kg) Used
57
Proceedings of the National Conference on “RECENT ADVANCES IN MANUFACTURING ENGINEERING & TECHNOLOGY”
January 10-11, 2011
2.8.
Units Electricity Consumed= 4kwt
Energy
Cost : Rs. 28/2.8. Overhead cost:
Overhead costs include all expenditures that it
is not practical to account for individually but
that when summed up amount to a considerable
outlay. They include office costs, all indirect
personnel costs, taxes, insurance, transportation,
advertising and sales, and also auxiliary
consumables not specifically devoted to any
identified job. In practice it will usually be
defined as a certain percentage of Labor costs (i.
e. 150%) but any rate may be valid although
some effort should be exerted to attempt a
realistic figure.
Travelling Charges + etc.: Rs. 210/-
Electricity
Consumed
Overhead
Charges
Total Cost
2 Units
each
28/-
28/-
Travelling,
Handling
210/-
210/-
1030/-
1010/-
Table 5: - Total cost estimated foe MIG and
MAG
The only difference in MIG and MAG is the
shielding gas used. Carbon Dioxide is cheaper
than argon and oxygen also thus it’s easy to find
in urban Ares.
3. Conclusion:
There is no mystery in Welding-cost estimate: it
is mainly a question of common sense. But it
must be appreciated that correct accounting for
total Welding-cost incurred in a welding
operation is a preliminary requirement to the
assessment of the best practices and a necessary
tool for the economic management of any
welding enterprise.
It is estimated from the recorded data that except
material cost, cost division gained is shown in
fig-3.
2.9. Inspection cost:
For demanding application inspection costs may
involve the employment of sophisticated
techniques
(Ultrasonic
Testing
and/or
Radiographic Inspection) and of expert
technicians to carry them out. Inspection costs
depend mainly on quality requirements and will
be generally accounted for whole projects.
Inspection Cost: Nil
2.10. Finishing cost:
A certain number of operations may be required
after all welding is completed. There may be
final cleaning and grinding, spatter removal,
post weld heat treatment cycles, painting,
assembling for erection or disassembling for
transportation and any other activity specified in
the purchase order. Finishing Cost: Nil
Welding
Costs
Quantity
Mig
cost
Mag
cost
Rs.
Rs.
Fig-3 Cost divison
The reasons for estimating welding costs are
varied, but most often are to:
Base metal
cost
Preperation
cost
Weld Labor
cost
110
480 /-
480 /-
5 cutters +
112mins
220 /-
220/-
45 mins
50/-
50/-
Filler Metal
1.4-1.5 m
4-5 /-
4-5 /-
35 /-
15/-
3/-
3/-
Gas Cost
Equipment
Cost
-----4 mins




58
Compare the economics of welding with
some other method of fabricating or
manufacturing.
Provide data needed for bidding a job.
Establish information required in
making a decision between alternate
designs.
Evaluate
proposed
changes
in
procedures.
Proceedings of the National Conference on “RECENT ADVANCES IN MANUFACTURING ENGINEERING & TECHNOLOGY”
January 10-11, 2011

[9] J.P. Ganjigattia, Dilip Kumar Pratihar, a,
and A. Roy Choudhurya, 2007, “Global versus
cluster-wise regression analyses for prediction of
bead geometry in MIG welding process” ,
Journal of Materials Processing Technology,
Volume 189, Issues 1-3, 6 July 2007, 352-366.
[10] Welding Engineering by Dr R.S.Parmar,
M/s. Khanna Publishers.
[11] Welding Technology by Dr O.P.Khanna,
Dhanpat Rai & Sons.
[12]American Welding Society’s official
website (www.aws.org).
[13] International Organization of Standards
website (www.iso.org).
[14] M. Suban, J. Tusek, 2001, Dependence of
melting rate in MIG/MAG welding on the type
of shielding gas used, J. Mater. Process.
Technol. 119, 185–192.
Compare the economic advantages of
competing welding processes
In between MIG and MAG, as though cost
estimated here is low but if this cost is to be
estimated for industry where whole day welding
is done, than this difference will become large.
MAG is best, most applicable and cheapest
process for practical works. Most of the small
scale industries are using this process. This
study can help these industries to estimate cost
for welding of their work pieces as already bead
geometry study has been done on this material
[8].
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1998,“A fast and reliable cost estimation tool for
Hot-forged Parts”, 2nd International Conference
on Integrated Design and Manufacturing in
Mechanical Engineering, IDMME’ Compiègne
France, May 27-29; 985-992.
[2]
A.
JIMENEZ,
1995,
“Méthode
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pp. 19-25.
[3] Bouaziz, Z.; Ben Younes, J.; Zghal, 2002.
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[4] Shebab, E.; Abdalla, H., 2002. “An
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[5] Jong-Yun, J., 2002. “Manufacturing Cost
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[6] Ben-Arieh, D., 2000. “Cost estimation
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Industrial Engineering.
59
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