Lincoln Electric PRO 155, Operator'S Manual

Page: 28 / 46

B-15
PRO 155
B-15
LEARNING TO WELD
FIGURE B.23
Welding In The Vertical Position
Welding in the vertical position can be done either ver-
tical-up or vertical-down. Vertical-up is used whenev-
era larger, stronger weld is desired. Vertical-down is
used primarily on sheet metal 5/32
” (3.9 mm) and
under for fast, low penetrating welds.
Use of this unit on thicker materials than recom-
mended may result in poor welds. The welds may
“ look ” good, but may just be “ sitting ” on top, of
the plate. This is called “ Cold Casting ” and will
result in weld failure.
Vertical-up And Overhead Welding
The problem, when welding vertical-up, is to put the
molten metal where it is wanted and make it stay
there. If too much molten metal is deposited, gravity
will pull it downwards and make it
“ drip ” . Therefore, a
certain technique has to be followed.
When welding out-of-position, run stringer beads.
Don
’ t whip, break the arc, move out of the puddle, or
move too fast in any direction. Use Wire Feed Speed
(WFS) in the low portion of the range. The general
technique and proper gun angle is illustrated in Figure
B.24.
Generally, keep the electrode nearly perpendicular to
the joint as illustrated. The maximum angle above per-
pendicular may be required if porosity becomes a
problem.
FIGURE B.24
Vertical-down Welding
Refer to Figure B.25 Vertical-down welds are applied
at a fast pace. These welds are therefore shallow and
narrow and, as such, are excellent for sheet metal.
Vertical-down welds may be applied to 5/32
” (3.9 mm)
and lighter material.
Use stringer beads and tip the gun in the direction of
travel so the arc force helps hold the molten metal in
the joint. Move as fast as possible consistent with
desired bead shape.
The important thing is to continue lowering the entire
arm as the weld is made so the angle of the gun does
not change. Move the electrode wire fast enough that
the slag does not catch up with the arc. Vertical-down
welding gives thin, shallow welds. It should not be
used on heavy material where large welds are
required.
FIGURE B.25
45 °
WARNING
PROPER GUN ANGLE
FOR GMAW PROCESS
WELDING IN THE VERTICAL UP POSITION PROPER GUN ANGLE
FOR FCAW PROCESS
WELDING IN THE VERTICAL UP POSITION