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WELDING PROCEDURE
Before commencing, make sure that your hand held welding mask or welding helmet is in
position to protect your eyes. It is also advisable to wear gloves and clothing, which cover
the hands and arms to prevent flash burns.
1.
Striking Arc.
This is done by bringing the electrode into contact with the work piece using a light
tapping action and withdrawing to create a gap of 1.5 mm – 3.00 mm.
2.
Maintaining Arc.
Having created an arc, all that is necessary to maintain it is to proceed steadily in
one direction keeping the gap between the electrode and the work piece constant.
The electric current will flow through the electrode, across the arc gap, and in doing
so will melt the electrode core wire and protective flux. The electrode length will
gradually decrease as the metal is transferred to the work piece under a protective
slag formed by the flux. This slag can then be removed when cooled by lightly tap-
ping with a pointed tool or a welders chipping hammer.
3.
To stop welding
All that is required is to withdraw the electrode from the work piece - thus breaking
the circuit. Be careful with the end of the electrode, as it will be hot! Provided the
current setting is correct, the surface of the work piece will also melt by the intensity
of the electric arc. A degree of “penetration” is thereby obtained and a complete
“fusion” of the work piece and the deposited electrodes met
4.
Selection of electrode.
There is no hard and fast rule by which a particular gauge of electrode is selected.
Usually this is determined by, the type of weld required and the thickness of the work
piece.
E.g. a butt weld in 2.5mm sheet metal can be done by a 2.0mm or 2.5mm electrode,
the difference being that the 2.5mm electrode will do the job quicker. The table be-
low Gives guidance as to which electrode is most suitable according to the material
thickness.
This table is only a guide, and values given are an indication only.
ELECTRODE SIZE
MATERIAL THICK-
NESS (MILD STEEL
MM
(Weld Current) Amp
MM
2
55
1.6 - 2.5
2.5
55 - 90
2.5 - 4.0
3.2
90 - 135
4.0 - 6.0
4.0 135
-180 6.0 - 8.0
Содержание RXT170P
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