Stick electrodes can be classified according to their coating as under:
Type Code
Type
Coating
Characteristics
Type of Slag
-
Slag Removal Ability
Penetration Depth
-
Gap Bridging Ability
Weld Appearance
Characteristics
Electrode Manipula-
tion
O
Bare Electrode
finely distributed arc
stabilizers in the
electrode material
minimal slag
shallow
-
excellent
more difficult to weld
than any other stick
electrode
very high deposition
rate, minimal heat
stress, little heat
distortion
convex, coarsely
rippled
OO
Flux-Core Electrode
arc stabilizers rolled
into the electrode's
core
minimal slag
average to deep
-
excellent
slightly easier to
weld than bare
electrodes
good deposition
rate, minimal heat
stress, little weld
distorition,
especially for root
welds
convex
-
coarsely rippled
N
Titania Oxide Type
high contens of
titanium oxide
porous, even slag
blanket
-
easily removed
average
-
good to excellent,
depending on
coating thickness
weldability of fillet
welds improves with
increasing coating
thickness
general purpose
electrodes, for
steels sensitive to
welding conditions,
for thin plate
slightly convex to
flat, finely to
medium-coarsely
rippled
flat, finely rippled
Es
Acid-Coated Type
high contents of
heavy metal oxides
porous, even slag
blanket
deep
-
average
weldability of fillet
welds improves with
increasing coating
thickness
for steels sensitive
to welding
conditions, requires
good weld
preparation
Ox
Iron Oxide Type
high contents of iron
oxides
tight slag blanket of
evenly distributed
thickness
-
very easily
shallow
-
very poor
good weldability,
fillet welds in gravity
position only
for unalloyed low-
carbon steels,
requires good weld
preparation
concave, very finely
rippled
Kb
Basic Low-
Hydrogen Type
high contents of
calcium or other
alkaline carbonates
thick slag blanket
-
fair
medium
-
good
handling requires
some practice, in
particular when
setting electrode to
and removing from
weld
particularly suitable
for thick plate and
rigid assemblies, for
high-carbon steels,
for thermo steels
slightly convex,
medium-coarsely
rippled
Ze
Cellulose Type
high contents of
organic components
minimal, often
quickly solidifying
thin slag blanket
-
easy
deep
-
very good
good handling as
only minimal slag,
heavy fume
generation
for out-of-position
welding
slightly convex,
rippled
17
In addition to the electrodes types shown in the above table there are several special types available coded SO. Cast
iron electrodes, for example, fall into this class.
When buying Kb and So type electrodes make sure they are suitable for AC current. As far as the quality grades are
concerned, a higher number indicates a better grade quality. For common low-carbon steels grades 7 - 9 are best
suitable.
The last letter of the code shown on the stick electrode indicates the coating thickness.
d
=
light coating
m
=
medium coating
s
=
heavy coating