This document provides an overview of various welding processes and their history. It begins with a brief history of welding from biblical times to modern developments in the 20th century. It then provides more detailed descriptions and explanations of specific welding processes such as MIG welding, shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW/TIG), plastic welding techniques, ceramic welding and welding safety standards. Case studies on automated welding machinery and the American Welding Society are also summarized.

1. Welding 101
Matt Cloud, Jake Frank, Ian Duckett, Clifton
Cearley
Levi Porter
GMP Presentaion - Welding 3/31/09 1

2. The History of Welding Metal
• Biblical Times – Cain forged metals using an open hearth
flame
• 1881 – Russian inventor, Benardos demonstrated arc
welding
• 1892 – Morehead & Wilson discovered acetylene (5720 F)
• 1904 – Covered electrode patented
• 1924 – Atomic Hydrogen Welding Process (like MIG, but
with H as shielding gas)
• 1933 – Submerged Arc Welding
• 1939 – 1941 – Russell Meridith, TIG Welding
• 1949 – Glen Gibson, MIG Welding
• 1955 – Robert Gage, Plasma Torch and Process
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3. MIG Welding

4. Gas Metal Arc Welding (GMAW)
Formerly known as metal inert-gas
(MIG)

5. History
• Originally developed for welding aluminum
and other non-ferrous materials in 1940s
• Soon applied to steel, allowed for lower
welding time compared to other welding
processes

6. What is MIG?
• Semi-automatic or automatic arc welding
process in which a continuous and
consumable wire electrode and a shielding gas
are fed through a welding gun

7. • GMAW weld area. (1) Direction of travel, (2) Contact tube, (3) Electrode,
(4) Shielding gas, (5) Molten weld metal, (6) Solidified weld metal, (7)
Workpiece.

8. Specifics
• Electrode wire (0.6-6.4 mm diameter) can be
uncoated, solid or hollow tube with powered
alloy (flux) additions in center (metal-cored
electrode)
• Argon, Helium, O2 or CO2 used as shielding
gas, which is the primary protection for the
arc and molten metal  no flux needed

9. Specifics
• Weld current: <500 amps used, DC or AC
• Max penetration depth: 6-10 mm

10. Methods
• Globular
• Short-circuiting
• Spray
• Pulsed-spray

11. Advantages
• Faster than most other welding processes
• Gas metal arc process can be applied to all
metals
• No slag to be removed, unlike other welding
processes

12. Limitations
• More costly equipment than SMAW or FCAW
• Rarely used outdoors or in other areas of air
volatility
• Weld is prone to cracking

13. Applications
• Most common industrial welding process,
preferred for its versatility, speed and relative
ease of adapting the process to robotic
automation
• Automobile industry uses MIG almost
exclusively

14. Shielded Metal Arc Welding

15. Shielded Metal Arc Welding
• Manual arc welding process
• Electric current is used to form an arc
between the workpiece and the electrode
• Weld is produced using a consumable flux
coated electrode
• During welding the flux forms a layer of slag
and serves as a shielding gas to protect the
weld from atmospheric contamination

16. Process
• Electrode brought in
contact with workpiece
and then pulled away
slightly in a sweeping
motion to initiate the arc
• Electrode begins to melt
and the flux disintigrates
and forms a shielding gas
• As the weld solidifies, slag
floats to the surface to
protect the weld
• Slag is hammered away to
reveal the finished weld

17. Advantages
• Simple and versatile
• Unlimited upper bound on material thickness
• Skilled welders are able to use SMAW in any
position
• Significant investment from welding industry
Lincoln Electric
~30 different mild/low alloy steel electrodes
~20 different stainless steel electrodes

18. Disavantages
• Weld Splatter
• Porosity
• Poor Fusion
• Shallow Penetration

19. TIG/GTAW
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20. TIG Welding History
• Developed in 1940 by Northrup Aircraft
employee to weld Mg
• Originally called “Heliarc” from the helium
shielding gas
• Patent sold to Union Carbide
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21. GTAW/TIG Welding Components
Gas Tungsten Arc Welding / Tungsten Inert Gas
• Constant-current welding power supply
• Non-Consumable Tungsten Electrode
• Inert Shielding Gas – Usually argon or helium or
a mixture
• Optional Filler Rod
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22. TIG Welding Specifics
• Plasma consisting of ionized
gases and metal vapors
• Commonly used to weld thin
sections of stainless steel, nickel
and copper alloys, as well as
light metals such as aluminum,
magnesium, titanium
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23. TIG Welding Advantages
• Offers greater operator control than competing
procedures
• Stronger, higher quality welds
• Attractive “stitched” finish
• No “smoke and spatter”
• Some welds require no filler material (edge, butt
and corner joints)
• Highly resistant to cracking (ductile) and
corrosion over long time periods
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24. TIG Welding Disadvantages
• Many consider this the most difficult of all the
popular welding processes
• Torches often require a cooling system (such
as water cooled torches, 200-600 Amps)
• Requires venting of shielding gas and
particulate matter
• Speed of process
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25. TIG Welding Safety
• Intense ultraviolet radiation requires special
eye protection (welding helmet) and complete
skin coverage to avoid sunburn
• Requires ventilation of gases to avoid
asphyxiation or inhalation of dangerous fumes
• Be aware of fire hazard
GMP Presentaion - Welding 3/31/09 25

26. TIG Welding Major Players
• Miller • Lincoln Electric
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27. Plastic Welding
Processes to weld plastic parts

28. Plastic Welding Methods
• Hot Gas
• Speed Tip
• Extrusion
• Contact, Hot Plate
• High Frequency
• Ultrasonic
• Spin
• Laser
• Solvent

29. Typical Types of Plastic Welding
• Hot Gas
– Freehand
– Uses hot air to melt plastic welding rod
• Speed Tip
– Heats and presses molten weld rod into
part
• Extrusion
– Bigger welds, single pass
• Contact
– Like spot welding
• Hot Plate
– Like contact

30. Other Plastic Welding Methods
• High frequency
– Only available for use with plastics such as PVC, PA, and acetates
– Plastic is heated using high frequency electromagnetic waves and parts
are joined
• Ultrasonic
– Similar to high frequency
– Energy concentrated for maximum weld strength
• Spin welding
– One part spun at high velocity. This part is then pressed against another
fixed part with a lot of force.
• Laser
– Wavelengths vary from 808 nm to 980 nm
– Power levels from 1W to 100W needed depending on material thickness
and process speed
• Solvent
– Use solvent to dissolve polymers in both parts to mix

31. Ceramic Welding
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32. History
- The ceramic welding process
was developed and originally
designed for the repair of
glass furnaces.
-In 1979 the technology was
introduced to the United
States as a method to repair
coke oven walls in the steel
industry.
-Since then the process has
evolved to include other
industries, primarily glass,
aluminum, copper, foundry
and cement.
GMP Presentaion - Welding 3/31/09 32

33. Process
-In ceramic welding processes,
oxidizing gas and a mixture of
refractory and fuel powders are
projected against a surface.
-The fuel is burnt to generate
sufficient heat so that the
refractory powder becomes at
least partially melted or softened
and a cohesive refractory mass is
progressively built up against that
surface.
-No arch like there is in TIG, MIG
or stick, but has a similar idea as
sintering in PM
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34. Components
Power- fuel powder is present in a
proportion of no more than 15% by
weight of the total mixture and
includes at least two metals selected
from aluminum, magnesium,
chromium and zirconium.
- the major part by weight of the
refractory powder consists of one or
more of magnesia, alumina and
chromic oxide.
Welder- a lance is used to deliver the
powder and oxidizing gas to the weld
area.
- hopper is used to hold the powder
mixture.
- welder can project up to 2 kg/min
of material to the weld site, but there’s
better quality of the weld at lower
rates.
Inspection of weld and weld area- a
camera can be attached to the lance or
a endoscope to inspect the weld.
GMP Presentaion - Welding 3/31/09 34

35. Uses and
Advantages
•Mostly used for repairs of the
brick lining in furnaces for glass
furnaces.
•Used to hold the refractory brick
lining in place by welding to brick
to steel rods in the furnace.
•Can be done while furnace is still
hot, preventing long durations of
down time for cool down.
•Lengthens the operational life
time of a furnace
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36. Welding Safety (ANSI Z49.1)
• 4.1 Protection of the general area
– Signs and warnings
– Equipment located/placed to prevent hazards in the workplace
– Protect personnel from welding areas via tall, fire resistant, protective
shielding and screening or require protective clothing
• 4.3 Protective Clothing
– Correct welding helmet/eye protection with respective shading
– Flame resistant gloves, aprons, leggings capes and sleeves
– Heavier clothing
• These standards and more can be found on the American Welding Society
website
• www.aws.org

37. American Welding Society
• Nonprofit organization devoted to advancing the
science, technology, and application of welding
and allied joining and cutting processes
• Code and certification procedures (more than
100 published) provide industry standards for the
welding and joining of metals, plastics and other
materials
• Certification consists of detailed testing
procedures, renewal is typically required every 9
years at an AWS accredited testing facility
• ~ 50,000 members, primarily in the US

38. Case Study
PANDJIRIS Automated Welder
At
ZAK, Inc.
GMP Presentaion - Welding 3/31/09 38

39. The Machine
Itself
- Consists of a travel beam, carriage and
rolling mounts.
-There are 6 axis of motion with two being
manually set before weld operation begins
with a total of 6 DOF
-Uses a TIG welding tip that uses helium as a
cover gas and the titanium electrode is water
cooled.
-Capable of welding a wide range of metals
because the welding tip can be changed to a
MIG tip as well and weld (Aluminum,
stainless steel, steel and bronze)
-Used to weld copper at ZAK, Inc. for
crucibles.
GMP Presentaion - Welding 3/31/09 39

40. Reasoning on
Purchase and Set-up
for the Machine
-Reliability and consistency of the weld vs. a
manual weld.
-Faster bead speed of 4-5 lbs/hr vs. 2 lbs/hr
manually.
-Faster part set-up.
-Took a year to get the welder into the shop
from first price quote to the first test run in
the shop
-Sent one operator away for 2 days for
training.
-Saves on average $6,500 in underling cost
per crucible in hope of resulting in a larger
market share.
-Estimated 2-5 years in return on investment.
GMP Presentaion - Welding 3/31/09 40

41. Disadvantages
and Problems
-Takes up a permanent floor space
-More weld material is needed to fill the
weld zone
-Must still have a skilled welder around when
operating the machine to continually inspect
the weld
-Total cost for the welder was about
$250,000 with an additional $20-$30,000 in
training cost.
-Now spend $6/lbs on the wire used to fill
the weld
-Cleaning and prepping the weld site is more
involved.
-Tubes tend to deform by tear dropping or
bowing from the heating of the work piece
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