Tungsten Inert Gas Welding

A brief description of Tungsten Inert Gas Welding

1. SEMINAR ON TIG WELDING
Presentedby
•AVINASHJURIANI14MT000354
M.TechMechanicalEngineeringSpecializationinManufacturingTechnology2014-2016

2. TIG WELDING
Background
•Initiallydevelopedin1941by
RusselMeredithforwelding
magnesium,asitsoxideshavehigh
m.p.thanparentmetal
•TIGdesignatednowadaysas
GTAW(Gastungstenarcwelding)
•Currentlyusedforwelding
aluminium,stainlesssteel,titanium,
nickel,copper,etc.
•Highlyattractivereplacementforgas
weldingasinertgasisusedfor
shieldinginsteadofslag

3. THE TIG PROCESS
Working
•Arcisstruckbetweenthenon-consumable
tungstenelectrodeandtheworkpiecetofuse
metals
•Arciscoveredbyalayerofshieldinggaswhich
actsasthefluxandkeepsthenitrogenandoxygen
intheairfromcomingincontactwiththemolten
puddle.
•Whenthepuddleisformedonthebasemetal,the
torchismovedalongthejointuntiltheworkpiece
isfusedtogether
•Afillerrodmayormaynotbeused
•Ifafillerrodisused,itshouldbethesame
compositionasthebasemetal.
•Thefillerrodisfedmanuallyintotheleadingedge
ofthepuddle.
•Thetorchmaybemovedinasemicircularmotion
tovarythewidthofthebead.

4. FEATURES OF TIG WELDING
•Temperaturemaybeintherangeof10000k
•Automaticandmanualtechniquescanbeused
•TIGmaybedoneinallpositions.
•Metalthicknessupto5mm
•Weldspeedfrom8mm/sto50mm/s
•Withsuperiorarcandweldpuddlecontrol,cleanweldsare
produced
•Nosparksorspatterbecauseonlythenecessaryamountof
fillermetalisaddedtotheweldingpool.
•Nosmokeandfumesunless
•Nofluxrequiredasargongasprotectstheweldpoolfrom
contamination

5. W
ELDING
POSITIONS
Viewof
different
positions

6. TIG WELDING EQUIPMENT
•Welding current generator
DCSP/AC
•Electrodeleadhoseforcurrent,
maybeawoventubeorflexible
cable&shieldinggashose
•Gascylinderwithflowmeter
•Weldingtorch

7. TIG TORCH PARTS, ORIENTATION &
ELECTRODE GRINDING
•Nozzleforgasflow
•Collettoholdtungstenelectrode
•Gascapmadeofceramic
•Tungstenelectrodetobegrindedbeforeinsertinginto
collet

9. WELDING IN SIMPLE STEPS

10. WELDING PARAMETERS & PRACTICAL APPROACH

11. DCSP VS AC IN TIG
DCSP
•Higherpenetration
•Deeperweldpuddle
•62.5%ofheatatworkenables
thicksheetsweld
•Toweldmetalslikecopper,
stainlesssteel,etc.whichdo
notneedcleaningofoxide
AC
•Mediumpenetration
•Mediumdepth
•50%ofheatatbothelectrode
&workpieceenablesthin
sheetsweld
•Preferredforaluminium&
magnesium

12. TIG SHIELDING GASES
ARGON VS HELIUM
Argon
•Heavierinweight
•Goodarcstarting
•Lessbasemetaldistortion
•Goodcleaningaction
•Goodarcstability
•Focusedarccone
•Lowerarcvoltages
•10-30CFHflowrates
•Forthinsheets
Helium
•Fastertravelspeeds
•Increasedpenetration
•Difficultarcstarting
•Lesscleaningaction
•Flaredarccone
•Higherarcvoltages
•Higherflowrates(2x)
•Highercostthanargon
•Forthicksheets

13. ELECTRODE USAGE NOZZLES
•Puretungstenelectrodeshave
lowcurrentcapacity
•Toimprovetheelectrical
conductivity,smallamountsof
thoriaorzirconia
•Electrodeswith1percentthoria
areusedforweldsonaircraft,
missiles,nuclearreactors,and
heatexchangers
•ZirconiatedTungstenismost
commonlyusedforACwelding
ofaluminumandmagnesium
alloys,preferredwhenTungsten
contaminationofweldis
intolerable.
•Nozzlesaremadefromceramic,
metal,plastic,andPyrexglass
materials
•Ceramicnozzlesareusedonjobsup
to275amps.
•Metalnozzlesormetal-coated
ceramicnozzlesareusedonjobs
where300ormoreampsofcurrent
areneeded.

14. OVERVIEW OF TIG WELDS

15. ADVANTAGES & DISADVANTAGES
•Advantages
•Weldsmoremetals&metalalloys
•Highqualityandprecision
•Pinpointcontrol
•Aestheticweldbeads
•Nosparksorspatter
•Nofluxorslag
•Nosmokeorfumes
•Disadvantages
•Lowerfillermetaldepositionrates
•Goodhand-eyecoordinationa
requiredskill
•BrighterUVraysthanother
processes
•Slowertravelspeedthanother
processes
•Equipmentcoststendtobehigher

16. TIG EQUIPMENT SPECIFICATIONS

17. REFERENCES
http://fairfld61.files.wordpress.com/
http://www.wikihow.com/TIG-Weld
Atextbookofproductiontechnologybyp.c.sharma
s.chandpublications