WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 1
(5) Combat Vehicles. Tank hulls are constructed of armor plate
for protection of the crew and to which the internal and external
mechanisms of the tank are fastened to the hull. The suspension
system consists largely of castings and forgings.
Various
castings are used throughout the powertrain.
Component parts
that do not carry the driving power load can be repaired by
welding. In general, the repair of these parts requires special
precautions such as preheating, postweld heat treatments, and the
proper welding procedure. One of the principal repairs performed
on combat vehicles is welding damage sections of armor plate.
The technique for welding armor plate will be discussed in Task
2. The following paragraphs describe the type and techniques of
joint design.
4.
Welding Joint Design
a. General. The properties of a welded joint depend partly on
the correct preparation of the edges being welded.
The joint
edges should be cleaned of all rust, oxides and other impurities,
and prepared to permit fusion without excessive melting.
This
preparation is governed by the form, thickness, kind of metal,
the load to be supported, and the available means for preparing
the joint.
b. Types of Joints.
There are basically five types of joints
used to weld various forms of metal. These types of joints are
described in the following subparagraphs.
(1) Butt Joint (figure 5 on the following page).
This type
joint is used for joining the edges of two plates or surfaces
located approximately in the same plane.
Plain square butt
joints for thin metal sections are shown in figure 5, view A.
These joints are used for butt welding light sheet metal.
Butt
joints for heavy sections with several types of edge preparation
are shown in figure 5, views B through E.
These edges can be
prepared by flame cutting, shearing, flame grooving, machining,
chipping, or grinding. Plate thicknesses of 3/8 to 1/2 inch can
be welded using the single V or single U joints as shown in
figure 5, views B and C. The edges of heavier sections should be
prepared as shown in figure 5, views D and E. In general, butt
joints prepared from both sides permit easier welding, produce
less distortion, and ensure better weld metal qualities in heavy
sections than joints prepared from one side only.
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