784 Agricultural Mechanics and Technology Systems
Copyright Goodheart-Willcox Co., Inc.
Electrode Categories
AWS places SMAW electrodes into four
broad categories. The classifi cations are fast-
fi ll, fi ll-freeze, fast-freeze, and low-hydrogen.
Fast-Fill Electrodes
A fast-fi ll electrode has a heavy iron
powder fl ux. This type of fl ux increases the
deposition rate and produces a thick, easily
removed slag that promotes the formation
of a very smooth bead. Fast-fi ll electrodes
are often called cover rods in reference to the
smoothness of their beads. The arc length of
electrodes with thick iron powder fl uxes
appears short because it is mostly concealed
within the cup formed at the tip. An E7024
is an example of this type of electrode.
Fill-Freeze Electrodes
A fi ll-freeze electrode produces a medium arc and has a moderate
deposition rate. Fill-freeze electrodes produce beads with uniform ripple
patterns on their surfaces. Fill-freeze electrodes are particularly well suited
for use on sheet metal because warpage is minimized. An E6013 is an
example of this type of electrode.
Fast-Freeze Electrodes
A fast-freeze electrode provides deep penetration and only moderate
amounts of fi ll. The thin fl ux of fast-freeze electrodes burns away at a
comparatively rapid rate. The result is a shallow cup at the electrode tip that
leaves most of the arc exposed. The highly exposed arc has the appearance of
being more aggressive than the arc produced by other classes of electrodes.
The beads they produce have a light slag that may adhere to the weld. Fast-
freeze electrodes are preferred for out-of-position welding. E6010 and E6011
are common examples of fast-freeze electrodes.
Low-Hydrogen Electrodes
Low-hydrogen electrodes are all fi ll-freeze as well. They produce a
medium penetrating arc and have a smooth, moderately high deposition
rate. Special formulations in the fl ux reduce the formation of hydrogen
compounds in the weld that can lead to cracking. After being exposed to
the atmosphere for nine hours, low-hydrogen electrodes pick up enough
moisture to counteract the low-hydrogen characteristic. The moisture
absorbed into the coating can be transferred into the weld metal in the form
of hydrogen. The hydrogen can lead to under-bead cracking, sometimes
called hydrogen-induced cracking. The moisture does not affect the welding
performance of the electrode.
Goodheart-Willcox Publisher
Figure 29-11. Electrode types are identified by a standard
coding system.