Uni-Mig KUMJRRW200MIG Instruction Manual download pdf (Page 11)

Installation set up for MMA (Stick) Welding with RAZOR 165-200 MIG

(1) Turn the power source on and select the MMA function with the MIG/MMA selector switch.

(2) Connection of Output Cables

Two sockets are available on this welding machine. For MMA welding the electrode holder is shown

be connected to the negative socket, while the earth lead (work piece) is connected to the positive

socket, this is known as DC- polarity. However various electrodes require a different polarity for

optimum results and careful attention should be paid to the polarity, refer to the electrode

manufacturers information for the correct polarity.

DC+ Electrode connected to output socket.

DC- Electrode connected to output socket.

(3) Set the welding current relevant to the electrode type and size being used as recommended by the

electrode manufacturer.

MMA (Manual Metal Arc) Welding

One of the most common types of arc welding is manual metal arc welding (MMA) or stick welding. An electric cur-

rent is used to strike an arc between the base material and a consumable electrode rod or ‘stick’. The electrode rod

is made of a material that is compatible with the base material being welded and is covered with a ux that gives off

gaseous vapours that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from

atmospheric contamination. The electrode core itself acts as ller material the residue from the ux that forms a slag

covering over the weld metal must be chipped away after welding.

Core wire

Flux coating

Gas shield from ux melt

Arc with core wire melt

Flux residue forms slag cover

Weld metal

Power Source

▬

• The arc is initiated by momentarily touching the electrode to the base metal.

• The heat of the arc melts the surface of the base metal to form a molten pool

at the end of the electrode.

• The melted electrode metal is transferred across the arc into the molten pool

and becomes the deposited weld metal.

• The deposit is covered and protected by a slag which comes from the

electrode coating.

• The arc and the immediate area are enveloped by an atmosphere of

protective gas

Core wire

Flux coating

Base metal

Protective gas

Arc

Slag

Weld pool

Manual metal arc ( stick) electrodes have a solid metal wire core and a ux

coating. These electrodes are identied by the wire diameter and by

a series of letters and numbers. The letters and numbers identify the metal

alloy and the intended use of the electrode.

The Metal Wire Core works as conductor of the current that maintains the arc.

The core wire melts and is deposited into the welding pool.

The covering on a shielded metal arc welding electrode is called Flux.

The ux on the electrode performs many different functions.

These include:

● producing a protective gas around the weld area

● providing uxing elements and deoxidizers

● creating a protective slag coating over the weld as it cools

● establishing arc characteristics

● adding alloying elements.

Covered electrodes serve many purposes in addition to adding ller metal to

the molten pool. These additional functions are provided mainly by the cover-

ing on the electrode.

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Uni-Mig KUMJRRW200MIG Instruction Manual Page 11

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