Welding

1
Welding
Welding 101

• Randy Amos
• William Philippin
• Hannah Porteous
• Brian Severino

2
What is Welding?

• Joining of component parts in a permanent bond
  through a combination of temperature, pressure,
  and metallurgical

3
History of Welding

• Bronze Age
• Iron Age
• Middle Ages
• WWI
• WWII
• 1950- 1970
• Today

4
Early History

• Bronze Age- swords joined by hard soldering
• Iron Age- Egyptians used pressure welding
• 310 C.E.- Iron Pillar of Delhi
• Middle Ages- Advances in forge welding
• Renaissance- welding used for sculpture

5
19th and 20th Centuries

• 1838 patents fusion welding
• 1865 patented the earliest form of electronic
  welding
• 1877-1903 development of gas welding
• 1890 first US patent for metal electrodes
• 1920 automatic welding developed using Direct
  Current

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Types of Welding
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Advantages

• Strength
• Smaller quantity- cheaper than casting
• Wide range of materials
• Allow large parts to be made in small sections
• Joins at an atomic level
• Versatility

8
Disadvantages

• Labor costs
• Defects caused by heating and cooling
• Monolithic
• Extremely dangerous without proper protection

9
Arc Welding

• Uses AC or DC power supply to create an arc to a
  grounded metal work piece melting the two
  materials together
• Two major forms are MIG and TIG welding

10
Metal Inert Gas (MIG) Welding

• Welding process utilizing a consumable electrode
  and shielding gas (to prevent corrosion) are fed
  through a gun.
• Originally developed in 1948 to weld aluminum and
  other non ferrite based materials.
• Was not widely used until the 1950s when the use
  of carbon dioxide as a shielding gas became
  popular and other changes were made to make it
  more effective at welding iron and steel as well
  as less expensive.

11
Materials that can be welded with MIG

• Aluminum
• Steel
• Magnesium
• Iron
• Stainless steel
• It is important to recognize that different
  metals will require a different kind of shielding
  gas.

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Uses of MIG welding

• Automotive Industry
• Can weld sheet metal as thin as 0.5mm
• Can be done almost exclusively by robots
• Can be setup with a continuous feed system
• Ship building
• Can be used to weld thick materials up to 1
  thick
• Can weld outside with the use of flux cored
  welding wire

13
Uses Continued

• General repair shops
• Railroad
• Furniture
• Structural steel in construction

14
MIG Costs

• If applied correctly can be the most cost
  effective form of welding.
• Dependant on many variables
• Type of weld joint
• Type of weld wire
• Type or shielding gas or flux core
• Labor costs
• Energy costs
• Transportation costs

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MIG Cost (continued)

• MIG welders come in various shapes styles and
  sizes for anyone from the hobbyist to the
  fabricator to industry

600
4000
30,000
16
MIG

• MIG is the quick and dirty method of welding
• Has a relatively short learning curve
• The majority of metal welding operations can use
  MIG
• May want to avoid for critical applications

17
Tungsten Inert Gas (TIG) welding

• Uses a non-consumable tungsten electrode that is
  used to melt two metals together in the presence
  of shielding gas.
• In some cases filler rod is used as well.
• Historically developed along side MIG welding
  with developments in electricity and shielding
  gasses.

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Materials that can be welded with TIG

• Can be used to weld nearly any commonly used
  metal with the exception of lead and zinc.
• Again different shielding gasses are used for
  different material.
• Also different types of power sources are used
  for different types of metal.

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Uses of TIG welding

• Oil Pipelines
• Medical Industry (SS)
• Exhaust piping
• Aluminum radiators

20
Costs

• Generally reserved for fabrication shops and
  Industry due to higher costs of welders
• Costs of TIG welding are very similar to MIG
  welding

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Cost (continued)

• Job shop TIG welder 3000

• Industrial TIG Robot 30,000

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Disadvantages of TIG vs MIG

• Cost of filler material and shielding gas are
  similar
• Higher skilled/paid employees are required for
  TIG
• More time for TIG
• Harder to automate a TIG process
• Outside welding is more difficult since the
  shielding gas can be blown away

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Advantages of TIG vs MIG

• TIG is irreplaceable in critical applications
• TIG has higher strength and heat resistance
• TIG is cleaner
• Can weld nearly any metal
• Can weld extremely thin materials (0.1mm)
• Can join metals without additional filler
  material in many cases.

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Laser-Beam Welding(LBW)
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Laser-Beam Welding (LBW)Characteristics

• Mechanics
• High-intensity, coherent beam of light, melts the
  bonding surfaces of a material inducing rapid
  coalescence
• Economics
• 1,000-20,000 small
• 20,000-100,000 med
• 100,000 and up large
• Time Span
• Set-up times are short
• 1-3 months
• Weld speeds
• 120 m/min
• Depend on depth of weld

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Laser-Beam Welding (LBW)Characteristics

• Constraints
• Thickness of materials
• Computer controlled traditionally
• Adequate power
• Line of sight
• High precision fixturing
• Uncertainties and reliability
• Highly reliable if process is well controlled and
  precisely fixtured
• Skills
• Can be fully automated
• Flexibility
• Process is highly adaptable to various part
  designs and demands
• Process capability
• Highly accurate and precise

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Top/Side and Cross-section of Laser Welds

• thickness 3 mm
• speed 1.5m/min

• thickness 12mm
• speed 2.2m/min

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Pictures LBW Devices
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Laser-Beam Welding (LBW)Process Summary

• Heat source
• Laser Light
• Protection
• None, or externally supplied gas
• Electrode
• None
• Rate of Heat Input
• High 106 W/mm2
• Weld profile (depth/width)
• 5 mm/mm
• Maximum penetration
• 25 mm
• Material Joined
• All common metals
• Thermoplastics
• Circuit components

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LBW Process Summary (continued)

• Assets
• Precision
• High heat-transfer efficiency
• Capable of welding any light-accessible location
• Small HAZ
• Low distortion
• High welding speeds
• Autogenous
• No filler material required

• Limitations
• Possible problems with reflectivity of certain
  metals
• High Precision positioning and fit-up required
• Computer controlled
• Work-holding
• Eye Hazard
• Absolute safety precautions must be adhered
• Line of sight required

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Friction-Stir Welding
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FSW Characteristics

• Mechanics
• Welding tool spins, melting and stirring bonding
  surface
• Economics
• Tooling and engineering costs are presently very
  high
• Process capability
• Butt joints
• Surface treatment
• Constraints
• Thickness of material
• Computer control
• High powered, precision fixturing
• Uncertainties and reliability
• Welding tool abrasion
• Highly reliable if process is well controlled and
  properly fixtured
• Time Span
• Set-up times
• 3-6 months
• Weld speeds

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Grain refinement in FSW
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Tooling, fixturing and plates used in FSW

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Friction-Stir Welding (FSW)Process Summary

• Heat source
• Friction
• Protection
• None
• Electrode
• None
• Material Joined
• Lower melt point metals
• Thermoplastic polymers

• Rate of Heat Input
• 2-3 X 103 W/mm2
• Weld profile (depth/width)
• 2 mm/mm
• Maximum penetration
• 65 mm single side
• 75 mm double side

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FSW Process Summary (continued)

• Assets
• Excellent weld quality
• Ultra fine grain refinement
• Wide range of materials
• Including some unweldable materials
• Low distortion
• High joint strength
• No loss of alloy elements
• No cracking
• No shield gas required
• No pre- or post- finishing processes required
• Autogenous

• Limitations
• High power, precision positioning and tooling
  required
• High force required to move weld tool through
  material
• Powerful fixtures required
• High welding tool wear rate

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Hybrid Welding Processes

• Processes incorporating various welding
  processes, combining their strength and minimize
  their weaknesses
• Laser and Arc (LBW and GMAW)
• Laser provides
• Deep penetration, Low distortion, High-welding
  speed
• Arc provides
• Wider weld pool, Gap-bridging capability,
  Shield-gas
• Laser assisted Friction-Stir Welding (LAFS)
• Laser provides
• initial heat to pre-heat material
• Minimizing FSW force requirements, fixturing
  strength and tool wear
• Friction-Stir provides
• Excellent weld strength, Expanded material
  selection,
• Lack of pre- and post-processing

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Hybrid (GMAW and LBW)Gas Metal Arc-Laser Welding
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Hybrid (LAFS)Laser Assisted Friction-Stir Welding
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Ultrasonic Welding

• High Frequency (15 kHz to 40 kHz ) low amplitude
  vibration
• 1960 Sonobond Ultrasonics, originally
  Aeroprojects Incorporated

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Ultrasonic Welding (Process)

• Mainly used for plastics
• Plastic Car

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Ultrasonic Welding (Applications)

• Computer electrical industries
• Aerospace automotive industries
• Medical industry
• Packaging industry

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Safety

• Exposure to high heat levels and voltages
• Creates annoying sound

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Ultrasonic Welding (examples)

• AML
• Hands clear system
• Annoying high pitch noise
• Examples
• Good
• Bad
• And the Ugly

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Tissue Welding (Case Study)

• Vascular tissue welding of the CO2 laser
• Laser-assisted skin closure at 1.32 microns
• Argon laser vascular tissue fusion
• Thermal Therapy, Laser Welding, and Tissue
  Interaction electronic resource

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Case Study Video

• http//www.youtube.com/watch?vFuTaP2QPIGs
• Total, 6 min video start at 415