WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 2
with downhand (flat position) electrodes unless the parts are
positioned properly.
Step 4. Check for the proper joint preparation.
Make sure all
joints are properly prepared.
(5) Warping of Thin Plates.
Step 1. Check for shrinkage of the deposited weld metal. Select
an electrode with high welding speed and moderate penetrating
properties.
Step 2. Check for excessive local heating at the joint.
Weld
rapidly to prevent excessive local heating of the plates adjacent
to the weld.
Step 3. Check for proper preparation of the weld joint.
Avoid
an excessive root opening in the joint between the parts to be
welded.
Hammer the joint edges thinner than the rest of the
plates before welding.
Hammering elongates the edges and the
weld shrinkage causes them to pull back to the original shape.
Step 4. Check the welding procedure.
Use either the special
intermittent or alternating welding sequence, or backstep or skip
welding procedure.
Step 5. Check the clamping of parts.
Properly clamp
parts
adjacent to the joint.
Use backup fixtures to cool
parts
rapidly.
10. Conclusion
This task served to describe the theory, principles, and
procedures of welding armor plate; the methods of destructive and
nondestructive testing of welds, and the troubleshooting of welds
pertaining to electric arc welding. This task completes the text
material of this lesson.
The next task consists of a practical
exercise which you are required to complete by providing the
answers to the questions.
102
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