MIG-MAG eng 260710 @1544

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    MIG/M

    AG&

    FluxCoredArcWelding

    KorayYU

    RTIIK

    [email protected]

    ail.com

    [email protected]

    tu.edu.tr

    MIG/MAG

    &FluxCoredArcWelding,2of85

    Content

    ReviewofPartIandII

    Definition

    Advantages

    Disadvantages

    ApplicationFields

    Equipment

    FillerMetals(Wireelectrodes)

    ShieldingGases

    InternalControlSystem(Principle)

    ForcesactingontheA

    rc

    TypesofArc

    Setting-upofaMIG/MAGW

    eldingUnit

    WeldingParameterInfluences

    PulsedArc

    PossibleDefectswhenMIG/MAGWelding

    WeldBevelPreparation

    Backing

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    MIG/MAG

    &FluxCoredArcWelding,3of85

    Definition

    Afixedcompositionofgasshieldstheweldmetal.

    Fillermetalisanelectrode

    atthesametime(a

    differencew.r.t.TIG)

    Fillermetaliscontinuous(adifferencew.r.t.TIG&

    MMA)

    NaturallybornSemi-mechanized

    DCEP(reversepolarity),

    DCENisseldomused

    becauseofpoortransfer

    ofmoltenmetalfromthewireelectrodetothe

    workpiece.

    Advantages

    Allpositionsareavaila

    ble

    Lessandsometimese

    vennoslagremoval(man-

    hour),

    MetalDepositionRate

    ishigh,

    Fast(2timesmoretha

    nMMA),

    Lessdistortion,

    Lowcostfillermetal(w

    .r.t.MMA&UP)

    Disadvantages

    LackofFusion

    Atstart

    Fillermetalmeltsontocold

    substrate

    Whenlowlinear

    weldingspeed

    Weldpoolflowinginfrontofthearc

    Sensitivetoenvironme

    ntalconditions

    MIG/MAG

    &FluxCoredArcWelding,4of85

    FieldsofApplication

    Constructionalsteeloralu

    minummembers,

    Shipyards,

    Automotive,

    PipeLines,

    PressureVesselsandProcessingEquipments,

    HeatExchangers,Boilers,Piping

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    MIG/MAG

    &FluxCoredArcWelding,5of85

    Eq

    uipment

    Powersupply

    Wirefeedunit

    Hoseassembly

    Torch

    Blowtorch

    Powersupply

    Wirefeed

    unit

    Hoseassembly

    Torch

    Blowtorch

    Ves

    selof

    Shieldinggas

    Wo

    rkpiece

    Neutralcable

    Wireelectrode

    Arc

    .

    MIG/MAG

    &FluxCoredArcWelding,6of85

    Po

    werSupply

    Constantpotentialpowersupply

    Thepotentialchangeb

    etween3to5Voltscorrespo

    ndstocurrentamplitudeof100A

    Selfcorrectingarc

    Kuralolarakgelemanlarayarlanabilenendktan

    sasahiptir.

    Endktanskaynakakmndakisapmalarazaltrveakmart

    hzndeitirir.rneintutuma

    srasndahzlbirakmartavantajlyken,ksadevreylearksrasndayavabirakmartdahaaz

    srantoluturur.

    Types;

    Conventional

    WithTrystor

    Withtransistorrectifier

    Withtransistorinverte

    r

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    MIG/MAG

    &FluxCoredArcWelding,7of85

    WireFeedUnit

    1.5m/min20m/min

    MIG/MAG

    &FluxCoredArcWelding,8of85

    WireFeedUnit

    1.5m/min20m/min

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    MIG/MAG

    &FluxCoredArcWelding,9of85

    WireFeedUnit

    Oneormorethanonedrivingunit

    arepossible

    MIG/MAG&

    FluxCoredArcWelding,10of85

    WireFeedUnit

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    MIG/MAG&

    FluxCoredArcWelding,11of85

    Ho

    seAssembly

    Carries;

    Coolingair(lower

    than250A)or

    water,

    Wireelectrode,

    Shieldinggas,

    Weldingcurrentand

    potential.

    MIG/MAG&

    FluxCoredArcWelding,12of85

    To

    rch

    (1)

    Torchhandle,

    (2)

    Mouldedphenolicdielectric(showninwhite)

    andthreadedmetalnutinsert(yellow),

    (3)

    Shieldinggasdiffuser,

    (4)

    Contacttip,

    (5)

    Nozzleoutputface

    [Reference:Mysid,TTlig

    htningRod]

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    MIG/MAG&

    FluxCoredArcWelding,13of85

    WireElectrodes

    WireElectr

    odes

    Solid

    FluxCo

    red

    Lessweldingcurrentforthe

    samemetaldepositionrate.

    Metalzl

    Crufzl

    Rutile

    Basic

    MIG/MAG&

    FluxCoredArcWelding,14of85

    WireElectrodes

    WireElectrodes

    forSteels

    Solid

    FluxCo

    red

    C-steel

    ISO17632

    StainlessSteel

    ISO17633

    C-steel

    ISO14341

    StainlessSteel

    ISO14343

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    MIG/MAG&

    FluxCoredArcWelding,15of85

    WireElectrodesIS

    O

    14341

    MIG/MAG&

    FluxCoredArcWelding,16of85

    ISO

    14341

    WireElectrodes

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    MIG/MAG&

    FluxCoredArcWelding,17of85

    ISO

    14341

    WireElectrodes

    MIG/MAG&

    FluxCoredArcWelding,18of85

    ISO

    14341

    WireElectrodes

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    MIG/MAG&

    FluxCoredArcWelding,19of85

    ISO

    14341

    WireElectrodes

    MIG/MAG&

    FluxCoredArcWelding,20of85

    ISO

    14341

    WireElectrodes

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    MIG/MAG&

    FluxCoredArcWelding,21of85

    ISO17632-

    WireElectrodes

    MIG/MAG&

    FluxCoredArcWelding,22of85

    ISO17632-

    WireElectrodes

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    MIG/MAG&

    FluxCoredArcWelding,23of85

    ISO17632-

    WireElectrodes

    MIG/MAG&

    FluxCoredArcWelding,24of85

    ISO17632-

    WireElectrodes

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    MIG/MAG&

    FluxCoredArcWelding,25of85

    Sh

    ieldingGases

    MIG/MAG&

    FluxCoredArcWelding,26of85

    Sh

    ieldingGases

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    MIG/MAG&

    FluxCoredArcWelding,29of85

    ForcesinArcandontotheDroplet

    20%

    100%Ar

    100%CO2

    Surface

    tension

    P

    incheffect;

    Anelectromagneticforc

    e

    Proportionaltothesquareofcurrentamplitude,I

    S

    urfacetension;

    Oxidepatchesonthed

    ropletredusethesurface

    tension

    Thehighersurfacetens

    ion,thebiggerdroplets

    M

    etalsevaporating;

    Pressureagainsttothe

    droplet

    P

    lasmabeam;

    G

    ravitation;

    MIG/MAG&

    FluxCoredArcWelding,30of85

    ProcessVariationsMetalTransfer

    S

    hortCircuitTransfer(ShortArc)Welding[15

    2

    0V]

    Metalistransferredfrom

    thewiretotheweld

    poolonlywhencontact

    betweenthetwois

    made,orateachshort

    circuit.

    Thewireshortcircuitst

    otheworkpiece20to

    200timespersecond

    Usessmallwireinther

    angeof.8to1.2mm

    diameter

    Operatesatlowarclen

    gths(lowvoltages)and

    weldingcurrents

    Fast-freezingweldpuddleisobtained

    Thisweldingtechnique

    isparticularlyusefulfor

    joining

    thinmaterialsina

    nyposition,

    thickmaterialsin

    theverticaland

    overheadposition

    ,

    andforfillinglargegaps

    Shortarcweldingshouldalsobeusedwhere

    minimumdistortionoftheworkpieceisa

    requirementbecauseofitslowheatinput

    C,M2andM3gases.

    Hardtocontrolandeas

    ytoleavedefect.

    V

    A

    20

    150

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    MIG/MAG&FluxCoredArcWelding,31of85

    ProcessVariationsMetalTransfer

    MIG/MAG&FluxCoredArcWelding,32of85

    G

    lobularTransfer(LongArc)Welding[>20

    V

    ]:

    Metaltransferringthrou

    ghthearc,

    Usually,thedropsofmoltenmetalhavea

    greaterdiameterthanthewireitself,

    Themetaltransferwith

    spatterand

    occasionalshortcircuiting,

    Occurswithgasescons

    istingmorethan

    20%CO2,

    Suchgaseshavegood

    thermal

    conductivity,sotheinte

    rfacebetweenthe

    electrodeandthearcis

    verynarrow,

    Nouseforhardwelding

    positions,

    Metaltransferefficiency

    isverylow,in

    between87and93%,

    Lackoffusionriskisve

    ryhigh.

    V

    A

    20

    150

    ProcessVariationsMetalTransfer

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    MIG/MAG&FluxCoredArcWelding,33of85

    S

    prayarc[higherthan25V

    ]:

    Byraisingtheweldingc

    urrentandvoltagestill

    further,themetaltransf

    erwillbecomeatruespray

    arc.

    Theminimumwelding

    currentatwhichthisoccursis

    calledthetransitioncurrent,abovethetransition

    currentpincheffectbecomeseffective.

    Thetransitioncurrent

    dependsonthemetalwire

    diameterandshieldin

    ggas.

    However,iftheshield

    inggasforweldingcarbonsteel

    containsmorethanabout20%CO2thereisno

    transitionfromglobulartransfertospraytransfer.

    Themoltendropsfrom

    thewireareverysmall,

    affordinggoodarcstability,shortcircuitingisrare.

    Littlespatter,highdepo

    sitionratesofweldmetal,

    morethan98%.

    3mmandgreaterinthickness

    V

    A

    20

    150

    ProcessVariationsMetalTransfer

    MIG/MAG&FluxCoredArcWelding,34of85

    S

    prayarc

    V

    A

    20

    150

    ProcessVariationsMetalTransfer

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    MIG/MAG&FluxCoredArcWelding,35of85

    P

    ulsedArc;

    Avariationofthespray

    arctechniqueisknownasp