Tabla de contenido
Publicidad
US
7.5.2
Striking the arc
SMAW welding may also be referred to as welding with coated electrodes. Striking
the arc melts the electrode, and its coating forms protective slag.
If, when striking the arc, the tip of the electrode is pressed against the metal, it
immediately melts and sticks to the metal, rendering continued welding impossible.
Therefore, the arc has to be struck in the same way that you would light a match.
Quickly strike the electrode against the metal and then raise it to give an appropriate
arc length (approx. 0.1 inch). If the arc is too long, it will crackle and split before
finally going out completely. Once the arc has been struck, move the electrode from
left to right. The electrode should be at an angle of 60° to the metal.
7.5.3
Manipulation of electrode
In SMAW welding, there are three motions to being matched in the end of electrode:
the electrode moving to the molten pool along axes [1]; a small oscillation maybe
neccessary to achieve the desired width of the melt pool [2]; the electrode moving
along welding way [3].
The operator can choose the manipulation of electrode based on welding joint sharp,
welding position, electrode spec, welding current and operation skill, etc.
workpiece
1 electrode moving
2 the electrode oscilliation (right and left)
3 the electrode move along weld
7.5.4
Anti-electrode pick-up
If, during the welding, the electrode would get in direct contact (touching) with the
workpiece to form short circuit, the welding current will drop to a miminum to prolong
the life of the electrode.
7.5.5
Joint forms in SMAW
Butt joint
bh43a
electrode
weld
Corner joint
- 14 -
Lap joint
T joint
© ESAB AB 2012
Publicidad
Capítulos
Tabla de contenido
