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 m etal 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.
Covered electrodes serve many purposes in addition to
filler metal to the molten pool. These additional functions are
provided mainly by the covering on the electrode.
3.2.4 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 supplier for the correct selection of electrode.
Electrode Size
The size of the electrode genera lly depends on
the thickness of the section being welded, and
the thicker the section the larger the electrode
required. The table gives the maximum size of
electrodes that maybe used for various
thicknesses of section base on using a general
purpose type 6013 electrode.
AverageThickness
of Material
MaximumRecommended
Electrode Diameter
1.0-2.0 mm
2.5 mm
2.0-5.0 mm
3.2 mm
5.0-8.0 mm
4.0 mm
>8.0 mm
5.0 mm