Figure 6-38.--Tee joint--single pass fillet weld.
Figure 6-40.--Lap joints.
to produce the single-V groove joint for the same plate
thickness. In general, butt joints prepared from both
You must take care to ensure penetration into the
sides permit easier welding, produce less distortion,
root of the weld. This penetration is promoted by root
and ensure better weld qualities in heavy sections than
openings between the ends of the vertical members and
joints prepared from one side only.
the horizontal surfaces.
TEE JOINTS.--Tee joints are used to weld two
LAP JOINTS.--Lap joints are used to join two
plates or sections whose surfaces are located
overlapping members. A single lap joint, where
approximately 90° to each other at the joint. A plain tee
welding must be done from one side, is shown in view
joint welded from both sides is shown in figure 6-38.
A of figure 6-40. The double lap joint is welded on both
The included angle of bevel in the preparation of tee
sides and develops the full strength of the welded
joints is approximately half that required for butt joints.
members (view B of fig. 6-40). An offset lap joint (view
Other edge preparations used in tee joints are
C of fig. 6-40) is used where two overlapping plates
shown in figure 6-39. A plain tee joint, which requires
must be joined and welded in the same plane. This type
no preparation other than cleaning the end of the
of joint is stronger than the single lap type, but is more
vertical plate, and the surface of the horizontal plate is
difficult to prepare.
shown in view A of figure 6-39. The single-beveled
EDGE JOINTS.--Edge joints are used to join two
joint (view B of fig. 6-39) is used in plates and sections
or more parallel or nearly parallel members. Edge joints
up to 1/2 inch thick. The double-bevel joint (view C of
are not very strong, and are used to join edges of sheet
fig. 6-39) is used on heavy plates that can be welded
metal, reinforcing plates in flanges of I-beams, and for
from both sides. The single-J joint (view D of fig. 6-39)
edges of angles. Two parallel plates are joined together,
is used for welding plates that are 1 inch thick or
as shown in view A of figure 6-41. On heavy plates,
heavier where welding is done from one side. The
double-J joint (view E of fig. 6-39) is used for welding
very heavy plates from both sides.
Figure 6-41.--Edge joints for light sheets and plates.
Figure 6-39.--Edge preparations for tee joint.