1、TIG Welding IntroductionTIG Welding Introduction2OutlineOutlineBackgroundBackground/Advantages & Disadvantages/Advantages & DisadvantagesSafetySafetyPreparation for TIG WeldingPreparation for TIG WeldingTechniques for Basic Weld JointsTechniques for Basic Weld JointsTIG Shielding GasesTIG Shielding
2、GasesWelding ParametersWelding ParametersTungsten Electrode SelectionTungsten Electrode SelectionConclusionConclusion3ConclusionConclusionTIG welding is an exciting skill that proves itself useful in TIG welding is an exciting skill that proves itself useful in countless applicationscountless applic
3、ationsBecause it welds more metal and metal alloys than any Because it welds more metal and metal alloys than any other process, TIG welding should be regarded as an other process, TIG welding should be regarded as an important tool where experience is the teacherimportant tool where experience is t
4、he teacherWelding parameters and tungsten electrode selection Welding parameters and tungsten electrode selection tables are recommended values and should be used as a tables are recommended values and should be used as a guidelineguidelineInformation presented here is only the tip of the iceberg, I
5、nformation presented here is only the tip of the iceberg, and further research and hands-on involvement should be and further research and hands-on involvement should be pursued to be comprehensivepursued to be comprehensive4BackgroundBackgroundWhat is TIG?What is TIG? Tungsten Inert GasTungsten Ine
6、rt GasAlso referred to as GTAWAlso referred to as GTAW Gas Shielded Tungsten WeldingGas Shielded Tungsten WeldingIn TIG welding, a tungsten electrode heats In TIG welding, a tungsten electrode heats the metal you are welding and gas (most the metal you are welding and gas (most typically Argon) prot
7、ects the weld from typically Argon) protects the weld from airborne contaminantsairborne contaminants5BackgroundBackgroundTIG welding uses a non-consumable TIG welding uses a non-consumable tungstentungstenFiller metal, when required, is added by Filler metal, when required, is added by handhandShie
8、lding gas protects the weld and Shielding gas protects the weld and tungstentungsten6AdvantagesAdvantagesWelds more metals Welds more metals and metal alloys than and metal alloys than any other processany other processHigh quality and High quality and precisionprecisionPin point controlPin point co
9、ntrolAesthetic weld beadsAesthetic weld beadsNo sparks or spatterNo sparks or spatterNo flux or slagNo flux or slagNo smoke or fumesNo smoke or fumes7DisadvantagesDisadvantagesLower filler metal Lower filler metal deposition ratesdeposition ratesGood hand-eye Good hand-eye coordination a required co
10、ordination a required skillskillBrighter UV rays than Brighter UV rays than other processesother processesSlower travel speeds than Slower travel speeds than other processesother processesEquipment costs tend to Equipment costs tend to be higher than other be higher than other processesprocesses8Saf
11、etySafetyElectric 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 se
12、curely in placeKeep all panels and covers securely in placeFumes 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 device9Sa
13、fetySafetyWelding 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 ov
14、er combustible surfaces Do not weld on closed containersDo not weld on closed containersArc rays can burn eyes and skin; Noise can Arc rays can burn eyes and skin; Noise can damage hearing.damage hearing. Wear welding helmet with correct shade of filterWear welding helmet with correct shade of filte
15、r Wear correct eye, ear, and body protectionWear correct eye, ear, and body protection10SafetySafetyHot 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 protec
16、tive gloves and clothingMagnetic fields from high currents can affect Magnetic fields from high currents can affect pacemaker operation.pacemaker operation.Flying metal can injure eyes.Flying metal can injure eyes. Welding, chipping, wire brushing, and grinding Welding, chipping, wire brushing, and
17、grinding cause sparks and flying metal; wear approved cause sparks and flying metal; wear approved safety glasses with side shieldssafety glasses with side shields11SafetySafetyWelding current can damage electronic parts in Welding current can damage electronic parts in vehicles.vehicles. Disconnect
18、 both battery cables before welding on a Disconnect both battery cables before welding on a vehiclevehicle Place work clamp as close to the weld as possiblePlace work clamp as close to the weld as possible12Techniques for Basic Weld JointsTechniques for Basic Weld JointsArc LengthArc LengthArc lengt
19、h normally one electrode diameter, when Arc length normally one electrode diameter, when AC welding with a balled end electrodeAC welding with a balled end electrodeWhen DC welding with a pointed electrode, arc When DC welding with a pointed electrode, arc length may be much less than electrode diam
20、eterlength may be much less than electrode diameter*Figure copied from “TIG Handbook”13Techniques for Basic Weld JointsTechniques for Basic Weld JointsGas Cup SizeGas Cup SizeInside diameter of gas Inside diameter of gas cup should be at least cup should be at least three times the three times the t
21、ungsten diameter to tungsten diameter to provide adequate provide adequate shielding gas coverageshielding gas coveragePicture on right shows Picture on right shows example of gas cup example of gas cup size and torch positionsize and torch position1-Workpiece, 2-Work clamp, 3-Torch, 4-Filler rod, 5
22、-Gas cup, 6-Tungsten electrode*Figure copied from “TIG Handbook”14Techniques for Basic Weld JointsTechniques for Basic Weld JointsElectrode ExtensionElectrode ExtensionRefers to distance the tungsten extends out Refers to distance the tungsten extends out beyond the gas cupbeyond the gas cupMay vary
23、 from flush with the gas cup to no more May vary from flush with the gas cup to no more than the inside diameter of the gas cupthan the inside diameter of the gas cupLonger the extension, the more likely it may Longer the extension, the more likely it may contact something by accidentcontact somethi
24、ng by accidentGeneral rule would be to start with an extension of General rule would be to start with an extension of one electrode diameterone electrode diameter15Techniques for Basic Weld JointsTechniques for Basic Weld JointsArc Starting with High Arc Starting with High FrequencyFrequencyTorch po
25、sition on left shows Torch position on left shows recommended method of starting recommended method of starting the arc with high frequency when the arc with high frequency when the torch is held manuallythe torch is held manuallyBy resting gas cup on base metal By resting gas cup on base metal ther
26、e is little danger of touching there is little danger of touching the electrode to the workthe electrode to the workAfter 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 49916Techni
27、ques for Basic Weld JointsTechniques for Basic Weld JointsManual Torch MovementManual Torch Movement*Figure copied from “TIG Handbook”17Techniques for Basic Weld JointsTechniques for Basic Weld JointsManual Torch MovementManual Torch MovementTorch and filler rod must be moved progressively Torch and
28、 filler rod must be moved progressively and smoothly so the weld pool, the hot filler rod and smoothly so the weld pool, the hot filler rod end, and the solidifying weld are not exposed to end, and the solidifying weld are not exposed to air that will contaminate the weld metal area or air that will
29、 contaminate the weld metal area or heat affected zoneheat affected zoneWhen arc is turned off, postflow of shielding gas When arc is turned off, postflow of shielding gas should shield the weld pool, electrode, and hot should shield the weld pool, electrode, and hot end of the filler rodend of the
30、filler rod18Techniques for Basic Weld JointsTechniques for Basic Weld JointsButt Weld and Butt Weld and Stringer BeadStringer BeadBe sure to center weld Be sure to center weld pool on adjoining pool on adjoining edgesedgesWhen finishing a butt When finishing a butt weld, torch angle may weld, torch
31、angle may be decreased to aid in be decreased to aid in filling the craterfilling the craterTorch and rod position for welding the butt weld and stringer bead*Figure copied from “TIG Handbook”19Techniques for Basic Weld JointsTechniques for Basic Weld JointsLap JointLap JointPool is formed so that t
32、he Pool is formed so that the edge of the overlapping edge of the overlapping piece and the flat surface piece and the flat surface of the second piece flow of the second piece flow togethertogetherTorch angle is important Torch angle is important because the edge will because the edge will become m
33、olten before the become molten before the flat surfaceflat surfaceEnough filler metal must Enough filler metal must be added to fill the joint as be added to fill the joint as illustrated on the rightillustrated on the rightTorch and rod position for welding the lap joint*Figure copied from “TIG Han
34、dbook”20Techniques for Basic Weld JointsTechniques for Basic Weld JointsT-JointT-JointEdge will heat up and melt Edge will heat up and melt soonersoonerTorch angle illustrated will Torch angle illustrated will direct more heat onto the direct more heat onto the flat surfaceflat surfaceElectrode may
35、need to be Electrode may need to be extended further beyond extended further beyond the cup in order to hold a the cup in order to hold a short arcshort arcTorch and rod position for welding the T-joint*Figure copied from “TIG Handbook”21Techniques for Basic Weld JointsTechniques for Basic Weld Join
36、tsCorner JointCorner JointBoth edges of the Both edges of the adjoining pieces should adjoining pieces should be melted and the pool be melted and the pool kept on the joint kept on the joint centerlinecenterlineSufficient filler metal is Sufficient filler metal is necessary to create a necessary to
37、 create a convex bead as shownconvex bead as shownTorch and rod position for welding the corner joint*Figure copied from “TIG Handbook”22TIG Shielding GasesTIG Shielding GasesArgonArgonHeliumHeliumArgon/Helium MixturesArgon/Helium Mixtures23TIG Shielding GasesTIG Shielding GasesArgonArgonGood arc st
38、artingGood arc startingGood cleaning actionGood cleaning actionGood arc stabilityGood arc stabilityFocused arc coneFocused arc coneLower arc voltagesLower arc voltages10-30 CFH flow rates10-30 CFH flow ratesHeliumHeliumFaster travel speedsFaster travel speedsIncreased penetrationIncreased penetratio
39、nDifficult arc startingDifficult arc startingLess cleaning actionLess cleaning actionLess low amp stabilityLess low amp stabilityFlared arc coneFlared arc coneHigher arc voltagesHigher arc voltagesHigher flow rates (2x)Higher flow rates (2x)Higher cost than argonHigher cost than argon24TIG Shielding
40、 GasesTIG Shielding GasesArgon/Helium MixturesArgon/Helium MixturesImproved travel speeds over pure argonImproved travel speeds over pure argonImproved penetration over pure argonImproved penetration over pure argonCleaning properties closer to pure argonCleaning properties closer to pure argonImpro
41、ved arc starting over pure heliumImproved arc starting over pure heliumImproved arc stability over pure heliumImproved arc stability over pure heliumArc cone shape more focused than pure heliumArc cone shape more focused than pure heliumArc voltages between pure argon and pure heliumArc voltages bet
42、ween pure argon and pure heliumHigher flow rates than pure argonHigher flow rates than pure argonCosts higher than pure argonCosts higher than pure argon25Welding ParametersWelding ParametersAluminum weld parameters*Figure copied from “TIG Handbook”26Welding ParametersWelding ParametersAluminum with
43、 advanced squarewave weld parameters*Figure copied from “TIG Handbook”27Welding ParametersWelding ParametersStainless steel weld parameters*Figure copied from “TIG Handbook”28Welding ParametersWelding ParametersTitanium weld parameters*Figure copied from “TIG Handbook”29Welding ParametersWelding ParametersMild steel weld parameters*Figure copied from “TIG Handbook”30Tungsten Electrode SelectionTungsten Electrode SelectionGuide to selecting a tungsten electrode based on amperage range*Figure copied from “Guidelines to Gas Tungsten Arc Welding (GTAW)”
