Cover ed electrodes serve many purposes in
addition to fil ler metal to the molten pool.
These additional functions are provided
mainly by the covering on the electrode.
2.7 Stick (MMA) Welding
Fundamentals
Electrode Selection
As a general rule, the selection of an
electrode is straight forward,in that it is
only a matter of selecting an electrode of
similar composition to the parent metal.
However, for some metals there is a choice
of several electrodes, each of which has
particular properties to suit specific classes
of work. It is recommend to consult your
welding suppli er for the correct selection of
electrode.
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 diferent functions.
These include:
• producing a protective gas around the weld area
• providing fluxing elements and deoxidizer
• creating a protective slag coating over the weld
as it cools
• establishing arc characteristics
• adding alloying elements.
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