788 Agricultural Mechanics and Technology Systems
Copyright Goodheart-Willcox Co., Inc.
the same vertical plane, and a butt weld is
placed between them along a horizontal line.
A horizontal fi llet weld (2F) is placed in
the joint between two parts, one located in
a vertical plane and fi tted to the surface of
the second part lying in a horizontal plane.
Vertical Position
Vertical welds (3G and 3F) are welded
similar to horizontal welds, except that the
welding progresses from top to bottom
(downhill welding, sometimes referred
to as vertical-down) or from bottom to top
(uphill welding, sometimes referred to
as vertical-up). Because gravity affects the
molten pool of vertical welds, a lower
amperage setting than that used when
welding fl at or horizontally is helpful to
control the weld pool. Best welding results
are achieved by maintaining a short arc,
moving the electrode at a uniform speed,
and feeding the electrode at a constant
speed as it melts.
Overhead Position
Welding in the overhead position (4G
and 4F) is like welding fl at, except that it is
upside-down. Due to the effect of gravity,
fast-freeze electrodes must be used. The
weld pool must resolidify quickly to reduce
dripping. A close fi t of parts to be welded,
with minimal gaps, reduces the heat required
for welding. The width of the molten pool
is kept small, and the amount of fi ll must be
limited on each pass. Multiple passes may
be needed on thicker material.
The term overhead can be misleading.
It refers to the position of the electrode,
which is pointing up at a downward facing joint, Figure 29-16. It does not
necessarily mean the joint is over the welder’s head. In fact, when welding
overhead, welders should make every attempt to position their bodies out of
the direct path of the resulting shower of hot slag and molten metal.
Pipe Welding Positions
Welding pipes that are fi xed in position requires a combination of
different welding positions in a single joint. For example, when joining two
Grooved Butt Welds
Flat 1G
Horizontal 2G
Vertical 3G
Overhead 4G
Fillet Welds
Flat 1F
Horizontal 2F
Vertical 3F
Overhead 4F
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Figure 29-15. Welding positions.