FCAW.ppt

FCAW

1. Flux-Cored Arc Welding (FCAW)
An arc welding process that uses an arc between
a continuous filler metal electrode and the weld
pool with shielding from a flux contained within
the tubular electrode or from an externally
supplied gas and without the application of
pressure

2. Flux-cored arc welding (FCAW)
•Flux-coredarcwelding(FCAW)isasemi-automaticor
automaticarcweldingprocess.
•FCAW requiresacontinuously-fedconsumabletubular
electrodecontainingafluxandaconstantvoltageor,less
commonly,aconstantelectriccurrent.
•Anexternallysuppliedshieldinggasissometimesused,but
oftenthefluxitselfisreliedupontogeneratethenecessary
protectionfromtheatmosphere.
•Theprocessiswidelyusedinconstructionbecauseofitshigh
weldingspeedandportability.
•FCAWovercomesmanyoftherestrictionsassociatedwith
SMAW.

3. Schematic Illustration for FCAW Process
Welding Direction

4. Types of FCAW
•Selfshieldingtype-thatrequiresnoshieldinggas
•Fluxcoreinthetubularconsumableelectrode
•Thiscorecontainsmorethanjustflux;italso
containsvariousingredientsthatwhenexposedto
thehightemperaturesofweldinggeneratea
shieldinggasforprotectingthearc
•ThistypeofFCAWispreferablebecauseitis
portableandhasexcellentpenetrationintothebase
metal.Also,theconditionsofairflowdonotneedto
beconsidered.

5. •Gasshieldingtype-usesashieldinggasthatmustbe
suppliedbyanexternalsupply
•Thistypewasdevelopedprimarilyforweldingsteels
•Sinceitusesbothafluxcoredelectrodeandanexternal
shieldinggas,onemightsaythatitisacombinationof
gasmetal(GMAW)andflux-coredarcwelding
•ThisparticularstyleofFCAWispreferableforwelding
thickerandout-of-positionmetals.Theslagcreatedby
thefluxisalsoeasiertoremove
•However,itcannotbeusedinawindyenvironmentasthe
lossoftheshieldinggasfromairflowwillproducevisible
porosityonthesurfaceoftheweld.

6. GAS SHIELD
SELF SHIELD

7. Advantages
•FCAWmaybean"all-position"processwiththerightfiller
metals.
•Noshieldinggasneededmakingitsuitableforoutdoorwelding
and/orwindyconditions.
•Ahigh-depositionrateprocess.
•Some"high-speed"(e.g.,automotiveapplications).
•Lessprecleaningofmetalrequired.
•Metallurgicalbenefitsfromthefluxsuchastheweldmetalbeing
protectedinitiallyfromexternalfactorsuntiltheslagischipped
away.
•Lowoperatorskillisrequired.

8. Disadvantages
•MeltedContactTip–happenswhentheelectrode
actuallycontactsthebasemetal,therebyfusing
thetwo.
•Irregularwirefeed–typicallyamechanical
problem.
•Porosity–thegases(specificallythosefromthe
flux-core)don’tescapetheweldedareabeforethe
metalhardens,leavingholesintheweldedmetal.
•Morecostlyfillermaterial/wireascomparedto
GMAW.

10. FLUX CORED ELECTRODE CONFIGURATIONS
BUTT LAP HEART
Metal Core
Flux

11. FLUX CORED ELECTRODE FORMING OPERATION
Strip steel
Flux Hooper
Flux Fill
“U” –Forming Rolls
Closing Rolls
To drawing operation

12. Functions of the Flux Ingredients

14. SLAG SYSTEMS

15. METHODS OF APPLICATIONS &
POSITION CAPABILITIES
Semiautomatic
Automatic
No manual process possible
All position welding

16. WELDABLE METALS & ALLOYS
•Best wieldable are
•Low carbon steels
•Low alloy steels
•High and medium carbon steels
•Alloy steels
•Certain grades of stainless steels
•Using spl electrodes
•Cast irons
•Nickel alloys

17. WELDABLE THICKNESS RANGES
#Depends on the type of shielding
#Self shielding = Less penetration
Max penetration is 6 mm
#Gas shielding = Deep penetration
Max penetration is 13 mm
#But with edge preparation,
Both types can go upto 19mm

18. JOINT DESIGN

19. WELDING CURRENT
•Similar to GMAW
•DCEP is most used
•DCEN is sometimes used
•DC –CV is the power source
•Current = 50 A –750 A
•AC can used with spl flux formulations
•CC power supply is then used

22. •Flux-cored electrodes are produced in
diameters ranging from 0.8 to 3.2 mm
•Electrodes for all-position welding may be
available in 0.8 mm , 0.9 mm , 1.2 mm , 1.4
mm , and 1.6 mm
•Electrodes for flat-and horizontal-position
welding may be available in 1.6 mm, 2.0 mm,
2.4 mm, 2.8 mm and 3.2 mm
•Other diameters may be made available by
agreement between the manufacturer and
the purchaser

23. Shielding Gases
Gas can be Inert, Reactive, or Mixtures of both
Gas flow rate is between 35-45 CFH
Argon and Carbon Dioxide are the main three
gases used in GMAW
Carbon Dioxide most used
Carbon Dioxide + Argon mixture sometimes used

24. DEPOSITION RATES & QUALITY OF WELDS
•High deposition rates
•High quality welds

25. LIMITATIONS & APPLICATIONS
•Only for ferrous alloys
•Removal of slag
•Expensive
•Replacing SMAW, GMAW (CO
2version) and
SAW for thinner materials
•Automotive industry, Pipe industry, Tank
industry, General construction industries