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Seminar Reporton

 Tungsten inert gas welding

Session- 2015-16

By

Rahul Shaw (12/MM/27)

Department of Metallurgical and Materials ngineering

 !ational "nstitute of #echnology$ Durgapur 

Mentor% Dr& S& '& Mitra

Contents

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Sl No. Title Page No.

1. Certifcate 0

2. ntroduction 1

!. "elding #peration 2-$

$. T%pes o& Tungsten 'lectrodes 5

5. T( S)ielding (ases 6

6. *ses +

+. ,dantages

. /isadantages

. ,pplications

10. Re&erences 10

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Certifcate

 T)is is to certi&% t)at t)is report on Tungsten nert (as"elding )as 3een carried out 3% Rahul Shaw4 fnal %ear

undergraduate student o& t)e /epartment o& etallurgical and

aterials 'ngineering at NT /urgapur under t)e superision o&

t)e undersigned.

Dr. S.K. Mitra

rofessor/epartment o& etallurgical and aterials 'ngineering

NT /urgapur

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1

1. INTRODUCTION

 Tungsten nert (as T(7 is an arc welding process t)at uses a

non-consuma3le tungsten electrode to produce t)e weld. T)e

weld area is protected &rom atmosp)eric contamination 3%

an inert s)ielding gas argon or )elium74 and a fller metal is

generall% used. ,lso re&erred to as (T," or (as S)ielded

 Tungsten "elding.

, constant-current welding power suppl% produces electrical

energ%4 w)ic) is conducted across t)e arc t)roug) a column o& 

)ig)l% ioni8ed gas and metal apour 9nown as a plasma. (T,"

is most commonl% used to weld t)in sections o& stainless steel

and non-&errous metals suc) as aluminium4 magnesium4 and

copper allo%s. T)e process grants t)e operator greater control

oer t)e weld t)an competing processes suc) as s)ielded metal

arc welding and gas metal arc welding4 allowing &or stronger4

)ig)er :ualit% welds. ;oweer4 (T," is comparatiel% more

comple< and di=cult to master4 and &urt)ermore4 it issignifcantl% slower t)an most ot)er welding tec)ni:ues. ,

related process4 plasma arc welding4 uses a slig)tl% di>erent

welding torc) to create a more &ocused welding arc and as a

result is o&ten automated.

 (T, welding can 3e used to &or nearl% all t%pes and t)ic9nesses

o& metal. (T, welding is ?u< less4 slag less4 and smo9eless.

"elders )ae fne control o& t)e welding process. (T, welding

is ideal &or close-tolerance welds. Some (T, welds ma9e t)ecritical root pass. (T, used w)en appearance is important.

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2

2. WELDING OER!TION

!.anual Torc) oement

 Torc) and fller rod must 3e moed progressiel% and smoot)l%so t)e weld pool4 t)e )ot fller rod end4 and t)e solidi&%ing weld

are not eected 8one.

")en arc is turned o>4 post?ow o& s)ielding gas s)ould s)ield

t)e weld pool4 electrode4 and )ot end o& t)e fller rod.

@ig 1A Torc) moement

@ig 2A Torc)

and

@iller

etal

positioning

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!

". Torch !n#le

,s close to perpendicular as possi3le. a% 3e angled 0-15

degrees &rom perpendicular &or 3etter isi3ilit%. ,s t)e gas ?owsout it &orms a protectie 8one around t)e weld. Too muc) tilt

distorts protectie s)ielding gas 8one. Belocit% o& s)ielding gas

a>ects protectie 8one. ow-pressure area deelops 3e)ind t)e

cup w)en elocit% increases. S)arper angle and )ig)er ?ow

rate increases contamination.

C. $iller Ro% &ani'ulation

@iller rod must 3e 9ept inside t)e protectie 8one. & fller rod is

remoed &rom t)e gas protection4 it o

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$

@igure $A Too muc) fller rod angle )as caused o

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5

(. T)'es o* Tun#sten

Electro%es

• ure tun#sten+ Green

  Pure Tungsten is an e

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6

  @ig5A

 Tungsten 'lectrodes

/. TIG Shiel%in# Gases

1. !r#onA t )as good arc starting4 good

cleaning action4 good arc sta3ilit%4 &ocused

arc cone4 lower arc oltages and 10-!0 C@;

?ow rates.2. 0eliu,A t gies &aster trael speeds4

increased penetration4 3ut di=cult &or arcstarting4 less cleaning action4 less low amp

sta3ilit%4 )ig)er arc oltages4 )ig)er ?ow

rates 2

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+

3. Uses

• (as tungsten arc welding is most commonl% used to weld

stainless steel4 mild steels and non&errous materials4 suc)

as aluminum and magnesium4 3ut it can 3e applied to

nearl% all metals.

•   ts applications inoling car3on steels are limited not

3ecause o& process restrictions4 3ut 3ecause o& t)e

e

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4. !%5anta#es• "elds more metals and metal allo%s t)an an% ot)er

process

• ;ig) :ualit% and precision

• ,est)etic weld 3eads

• No spar9s or spatter

• No ?u< or slag

• No smo9e or &umes

6. Disa%5anta#es• ower fller metal deposition rates

• (ood )and-e%e coordination a re:uired s9ill

• Grig)ter *B ra%s t)an ot)er processes

• Slower trael speeds t)an ot)er processes

• ':uipment costs tend to 3e )ig)er t)an ot)er processes

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7. !''lications• ")ile t)e aerospace industr% is one o& t)e

primar% users o& gas tungsten arc

welding4 t)e process is used in a

num3er o& ot)er areas.

•  an% industries use T( &or welding

t)in wor9pieces4 especiall%non&errous metals.

• t is used e

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10

RE$ERENCES

  ,merican "elding Societ% 200$7. "elding )and3oo94

welding processes Part 1.

   Ie>us4 arr% 20027. "eldingA Principles and

applications @i&t) ed.7.

  innic94 "illiam ;. 167. (as tungsten arc welding

)and3oo9.

  "eman4 Jlas 200!7. "elding processes )and3oo9

  )ttpsAKKen.wi9ipedia.orgKwi9iK(asLtungstenLarcLwelding