WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 1
c.
Classification of Electrodes.
(1) Metal-arc electrodes may be grouped and classified as bare
electrodes, thinly coated electrodes, and shielded-arc or heavy
coated electrodes.
A classification number series, (formulated
by the American Welding Society), has been adopted by the welding
industry for the identification of electrodes. By means of this
numbering system, the following characteristics of a given
electrode can be identified:
(a) Whether the electrode has a light or heavy coating.
(b) The composition of the coating.
(c) The recommended welding position.
(d) The type of electric current (direct or alternating
current) and the polarity for which the electrode is intended.
(e) The base metal for which the electrode is recommended.
(2) The identification system for steel arc welding electrodes
is a four digit number series preceded by a letter as described
below:
(a) The symbol E indicates that the electrode is intended for
use in electrical welding.
(b) The first two (or three) digits of the number indicate the
tensile strength (the resistance of the material to forces trying
to pull it apart), in thousands of pounds per square inch, of the
deposited metal.
(c) The third (or fourth) digit indicates the position of the
weld.
The number 0 in either one of these positions indicates
the classification is not used.
The number 1 indicates the
electrode may be used for all welding positions.
The number 2
indicates that the electrode may be used only in the flat and
horizontal positions. The number 3 indicates the electrode is to
be used only in the flat welding position.
(d) The fourth (or last) digit indicates the type of coating on
the electrode, and the power supply (either alternating current
(ac) or direct
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