Unimig KUMJRRW320ACDC, Руководство по эксплуатации

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Core Wire
Flux Coating
Gas shield from flux melt
Arc with core wire melt
Flux residue forms slag cover
Weld Metal
STICK (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.
• 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 a 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.
MMA (STICK) WELDING GUIDE
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