Thermal Arc 211i, Руководство по эксплуатации

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BASIC WELDING FABRICATOR 211i
Manual 0-5157 4-15 BASIC WELDING
D. Presetting
It is possible in some cases to tell from past experi-
ence or to find by trial and error (or less frequently,
to calculate) how much distortion will take place in a
given welded structure. By correct pre-setting of the
components to be welded, constructional stresses
can be made to pull the parts into correct alignment.
A simple example is shown in Figure 4-31.
E. Preheating
Suitable preheating of parts of the structure other
than the area to be welded can be sometimes used to
reduce distortion. Figure 4-32 shows a simple applica-
tion. By removing the heating source from b and c as
soon as welding is completed, the sections b and c
will contract at a similar rate, thus reducing distortion.
Art # A-07707
Figure 4-31: Principle of Presetting
Art # A-07708
B
Preheat Preheat
Dotted lines show effect if no preheat is used
Weld
C
Figure 4-32: Reduction of Distortion by Preheating
Art # A-07709
Figure 4-33: Examples of Distortion
Art # A-07710_AB
1
Block Sequence.
The spaces between the welds are
filled in when the welds are cool.
2
3
Figure 4-34: Welding Sequence
Art # A-07711_AB
4
3
2
1
Figure 4-35: Step back Sequence
Art # A-07428_AB
Figure 4-36: Chain Intermittent Welding
Art # A-07713_AB
Figure 4-37: Staggered Intermittent Welding