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Arc Welding

Shield metal AW Gas metal AW(MIG)

Gas tungsten AW(TIG)

Arc Welding ( 아크용접 ) : Electric discharge is heat sorce.

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Heat transfer in arc welding

• Welding speed ise = efficiencyV = voltage appliedI = currentu = specific energyA=weld section area

uA

VIev

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Shielded metal arc welding• SMAW ( 피복금속 AW) is the simplest and most

versatile joining process.• It uses a consumable electrode coated in flux giving off

a shielding gas.

http://www.youtube.com/watch?v=TeBX6cKKHWY&feature=related

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Submerged arc welding

• Weld arc is covered by a flux powder which is fed into the weld zone by gravity through a nozzle.

• Flux completely covers the molten metal and prevents weld from oxidization and spatter.

http://www.youtube.com/watch?v=Uns93e4HaNU&feature=related

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Gas metal arc welding

• GMAW( 가스방호 AW)= MIG (metal inert-gas welding)• Weld area is shielded by gas (Ar, He, CO2) to prevent

oxidation.

MIG: http://ma.gnu.ac.kr/vod/Joining/Metal_Inert_Gas_Welding.MP4

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Flux-cored arc welding

• FCAW ( 유심용제 AW) is similar to MIG but electrode is tubular and filled with flux.

• Continuous and automatic electrode feeding.

FCAW vs. MIG: http://www.youtube.com/watch?v=chE6RPhM3xE

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Electrogas welding

• EGW welds thick vertical edges in one pass with special equipment. A shielding gas is sometimes used. Used in shipbuilding and storage tanks.

http://www.youtube.com/watch?v=8nwP0JYQIdg

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Electroslag welding

• ESW is for thick (25~300mm) vertical edges.• Flux is added. After the molten slag reaches the tip of

the electrode, arc is extinguishes and energy is supplied through the electrical resistant of the molten zone.

http://www.youtube.com/watch?v=rCL8NCy2eg8

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Gas tungsten arc welding• GTAW( 텅스텐 AW)=TIG(Tungsten inert gas)• A filler metal is supplied from a filler wire.

http://www.youtube.com/watch?v=VEEpikDY058