LIBRARY ı6ıul 0) - Cranfield University

Step 11
Step 12
Step 13
Step 14
Step 15
Adjust the value of DCI to force the mode of metal transfer to either dip or
spray, based on the threshold limits shown in Figure 2.8 and on the
restrictions of mode of metal transfer imposed in the case of a gap being
present andlor the weld being positional:
If Imean
> 240 Amps then set the mode of metal transfer to spray (DCI
= 0.0)
If DCI indicates tendency to mixed globular and spray modes of metal
transfer (DCI < 0.3) then make sure the transfer mode is spray (DCI
= 0.0)
If DCI indicates tendency to wire stubbing in dip mode of metal
transfer (DCI > 0.75), make sure that this does not occur (DCI =
0.75)
If DCI indicates tendency to globular and mixed globular and spray
modes of metal transfer (DCI < 0.65) AND (there is a gap OR
positional welding) then force the metal transfer to the dip mode (DCI
= 0.65)
Estimate the welding voltage, Vmean
, using equation (3.13). This equation was
obtained by dividing both sides of equation (3.5) by VM. , rearranging the
terms and applying the definition of DCI from equation (2.5).
vvan 1- DCI - 65
(3.13)
Given the welding current, 'mean
, the welding voltage, V.,,.,, and the welding
speed, Sw, estimate the penetration by selecting the minimum between the
side penetration, Pen, , and the bottom penetration, Penb , which are
calculated by using equation (3.7) with the suitable regression constants (see
Table 3.1).
If the estimated minimum penetration is between 10% and 60% of the
minimum plate thickness, Tm,. , then calculate the possibility measure of good
arc ignition, using equation (3.9). Otherwise jump to Step 20.
If a good arc ignition is expected to occur (Pr(arc) < 0.4) then estimate the
possibility measure of undercut, Pr(und) Otherwise jump to Step 20.
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