TIG Welding TIG Welding IntroductionIntroduction

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BackgroundBackground

►What is TIG?What is TIG? Tungsten Inert GasTungsten Inert Gas

►Also referred to as GTAWAlso referred to as GTAW Gas Shielded Tungsten WeldingGas Shielded Tungsten Welding

► In TIG welding, a tungsten electrode In TIG welding, a tungsten electrode heats the metal you are welding and heats the metal you are welding and gas (most typically Argon) protects the gas (most typically Argon) protects the weld from airborne contaminantsweld from airborne contaminants

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BackgroundBackground

►TIG welding uses a non-consumable TIG welding uses a non-consumable tungstentungsten

►Filler metal, when required, is added Filler metal, when required, is added by handby hand

►Shielding gas protects the weld and Shielding gas protects the weld and tungstentungsten

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AdvantagesAdvantages

► Welds more metals Welds more metals and metal alloys and metal alloys than any other than any other processprocess

► High quality and High quality and precisionprecision

► Pin point controlPin point control► Aesthetic weld beadsAesthetic weld beads► No sparks or spatterNo sparks or spatter► No flux or slagNo flux or slag► No smoke or fumesNo smoke or fumes

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DisadvantagesDisadvantages

► Lower filler metal Lower filler metal deposition ratesdeposition rates

► Good hand-eye Good hand-eye coordination a required coordination a required skillskill

► Brighter UV rays than Brighter UV rays than other processesother processes

► Slower travel speeds Slower travel speeds than other processesthan other processes

► Equipment costs tend Equipment costs tend to be higher than other to be higher than other processesprocesses

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SafetySafety

► Electric shock can kill.Electric shock can kill. Always wear dry insulating glovesAlways wear dry insulating gloves Insulate yourself from work and groundInsulate yourself from work and ground Do not touch live electrical partsDo not touch live electrical parts Keep all panels and covers securely in placeKeep all panels and covers securely in place

► Fumes and gases can be hazardous to your Fumes and gases can be hazardous to your health.health. Keep your head out of the fumesKeep your head out of the fumes Ventilate area, or use breathing deviceVentilate area, or use breathing device

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SafetySafety

► Welding can cause fire or explosion.Welding can cause fire or explosion. Do not weld near flammable materialDo not weld near flammable material Watch for fire; keep extinguisher nearbyWatch for fire; keep extinguisher nearby Do not locate unit over combustible surfacesDo not locate unit over combustible surfaces Do not weld on closed containersDo not weld on closed containers

► Arc rays can burn eyes and skin; Noise Arc rays can burn eyes and skin; Noise can damage hearing.can damage hearing. Wear welding helmet with correct shade of Wear welding helmet with correct shade of

filterfilter Wear correct eye, ear, and body protectionWear correct eye, ear, and body protection

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SafetySafety

► Hot parts can cause injury.Hot parts can cause injury. Allow cooling period before touching welded Allow cooling period before touching welded

metalmetal Wear protective gloves and clothingWear protective gloves and clothing

► Magnetic fields from high currents can Magnetic fields from high currents can affect pacemaker operation.affect pacemaker operation.

► Flying metal can injure eyes.Flying metal can injure eyes. Welding, chipping, wire brushing, and Welding, chipping, wire brushing, and

grinding cause sparks and flying metal; wear grinding cause sparks and flying metal; wear approved safety glasses with side shieldsapproved safety glasses with side shields

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SafetySafety

► Welding current can damage electronic parts Welding current can damage electronic parts in vehicles.in vehicles. Disconnect both battery cables before welding on Disconnect both battery cables before welding on

a vehiclea vehicle Place work clamp as close to the weld as possiblePlace work clamp as close to the weld as possible

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Techniques for Basic Weld Techniques for Basic Weld JointsJoints

Arc Starting with High Arc Starting with High FrequencyFrequency

► Torch position on left shows Torch position on left shows recommended method of recommended method of starting the arc with high starting the arc with high frequency when the torch is held frequency when the torch is held manuallymanually

► By resting gas cup on base metal By resting gas cup on base metal there is little danger of touching there is little danger of touching the electrode to the workthe electrode to the work

► After arc is initiated, torch can be After arc is initiated, torch can be raised to proper welding angleraised to proper welding angle

*Figure copied from “TIG Handbook”

ENBE 499 11

Techniques for Basic Weld Techniques for Basic Weld JointsJoints

Manual Torch MovementManual Torch Movement

*Figure copied from “TIG Handbook”

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TIG Shielding GasesTIG Shielding Gases

►ArgonArgon►HeliumHelium►Argon/Helium MixturesArgon/Helium Mixtures

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TIG Shielding GasesTIG Shielding Gases

ArgonArgon► Good arc startingGood arc starting► Good cleaning actionGood cleaning action► Good arc stabilityGood arc stability► Focused arc coneFocused arc cone► Lower arc voltagesLower arc voltages► 10-30 CFH flow rates10-30 CFH flow rates

HeliumHelium► Faster travel speedsFaster travel speeds► Increased penetrationIncreased penetration► Difficult arc startingDifficult arc starting► Less cleaning actionLess cleaning action► Less low amp stabilityLess low amp stability► Flared arc coneFlared arc cone► Higher arc voltagesHigher arc voltages► Higher flow rates (2x)Higher flow rates (2x)► Higher cost than argonHigher cost than argon

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TIG Shielding GasesTIG Shielding Gases

Argon/Helium MixturesArgon/Helium Mixtures► Improved travel speeds over pure argonImproved travel speeds over pure argon► Improved penetration over pure argonImproved penetration over pure argon► Cleaning properties closer to pure argonCleaning properties closer to pure argon► Improved arc starting over pure heliumImproved arc starting over pure helium► Improved arc stability over pure heliumImproved arc stability over pure helium► Arc cone shape more focused than pure heliumArc cone shape more focused than pure helium► Arc voltages between pure argon and pure heliumArc voltages between pure argon and pure helium► Higher flow rates than pure argonHigher flow rates than pure argon► Costs higher than pure argonCosts higher than pure argon