Mma (Stick) Welding Guide - Unimig VIPER Operating Manual

MMA (STICK) WELDING GUIDE

MMA (MANUAL METAL ARC) WELDING
One of the most common types of arc welding is manual metal arc welding (MMA) or MMA welding. An electric current 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 flux 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 filler material the residue from the flux that forms a slag covering over the
weld metal must be chipped away after welding.
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Power Source
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Core wire
Flux coating
Base metal
Protective gas
Arc
Slag
Weld pool
36 | VIPER MIG 185 Manual
Core wire
• 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
Manual metal arc ( stick) electrodes have a solid metal wire core and a flux coating. These electrodes
are identified 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 flux on the electrode
performs many different functions.
• These include:
• Producing a protective gas around the weld area
• Providing fluxing elements and de-oxidisers
• 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 filler metal to the molten pool. These
additional functions are provided mainly by the covering on the electrode.
Flux coating
Gas shield from flux melt
Arc with core wire melt
Flux residue forms slag cover
Weld metal