Thermal Arc 175 SE ARC MASTER - Page 36

ARC MASTER 175 SE OPERATION
Manual # 0-5054 4-10 March 20, 2008
E. Preheating
Suitable preheating of parts of the structure other
than the area to be welded can be sometimes used
to reduce distortion. Figure 4-23 shows a simple
application. 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 4-22: Principle of presetting
Art # A-07708
B
PreheatPreheat
Dotted lines show effect if no preheat is used
Weld
C
Figure 4-23: Reduction of distortion by preheating
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Figure 4-24: Examples of distortion
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Figure 4-25: Welding sequence
Art # A-07711
Figure 4-26: Step back sequence
Art # A-07712
Figure 4-27: Chain intermittent welding
Art # A-07713
Figure 4-28: Staggered intermittent welding