The coating of these electrodes contains
organic materials that turn into gases
in the arc. About 30% of the coating weight is cellulose. In some
paper pulp and wood powder are added to the coating in certain ratios
the amount of pure cellulose. These organic compounds in the coating
in the arc to from carbon monoxide, carbon dioxide and hydrogen,
the arc tension and thus, the welding arc becomes stronger and harder.
with other types of electrodes, with the same current values, a
penetration is obtained with cellulosic electrodes.
This type of electrode is generally produced with thin or medium
thick nesses. When the coating is thin, a light amount of slag is
formed on the
welding beam and the spatter loss is high. On the other hand, the
and vertical down welding capability as well as penetration of the
by this electrode is good. Since this electrode can be used in every
(particularly in vertical down), it has a wide range of applications
in the ship
building industry and in the welding of pipelines with a wall thickness
than 12.5 mm. The cellulose that burns during welding forms a very
protective gaseous atmosphere.
The main features of cellulosic electrodes are as follows:
- Deep penetrating welding in every position,
- Vertical down welding capability,
- Weld metal with good mechanical properties.
The titanium compounds in the coating provide arc stability as well
as help clean
the slag easily. Adding a certain amount of ferromanganese to the
coating makes it
possible to compensate for the manganese that is lost through oxidation
during welding and to
deoxidize the weld pool. Since these electrodes are generally manufactured
using a sodium
silicate binder, they can best be used with DC(+).