Pass; Welding; Multiple Pass Welding; Special Welding Methods - Century OM-117071002 Operator's Manual

MULTIPLE PASS WELDING
Butt Weld Joints. In PREPARING THE
WORK PIECE, we discussed the need
for edge preparation on thicker materials
by grinding a bevel on the edge of one
or both pieces of the metal being joined.
When this is done, a V is created,
between the two pieces of metal, that
will have to be welded closed. In most
cases more than one pass or bead will
need to be rayed into the joint to close
the V. Laying more than one bead into
the same weld joint is known as a
multiple-pass weld.
NOTE: WHEN USING SELF-
SHIELDING FLUX-CORE
WIRE it is very important to
thoroughly chip and brush
the slag off each completed
weld bead before making
another pass or the next
pass will be of poor quality.
The illustrations in Figure 15 show the
sequence for laying multiple pass beads
into a single V butt joint.
Root Pass
Pass
Figure 15. Triple Pass V Butt Joint
Most fillet weld joints, on metals of
moderate to heavy thickness, will require
multiple pass welds to produce a strong
joint. The illustrations in Figure 16 show
the sequence of laying multiple pass
beads into a T fillet joint and a lap fillet
joint.
Lap Joint Welded
In Three Passes
Figure 16. Triple Pass Lap And T
Weld Joint
SPECIAL WELDING
METHODS
SPOT WELDING
The purpose of a spot weld is to join
pieces of metal together with a spot of
weld instead of a continuous weld bead.
There are three methods of spot
welding: Burn-Through, Punch and Fill,
and Lap (see Figure 17). Each has
advantages and disadvantages
depending on the specific application as
well as personal preference.
PUNCH A ND FILL
BURN THROUGH
LAP SPOT
Figure 17. Spot Weld Methods
1. The BURN-THROUGH METHOD
welds two overlapped pieces of
metal together by burning through
the top piece and into the bottom
piece.
0.030 inch self-shielding flux-core wire
should not be used with the burn-
through method unless the metal is
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