LIBRARY ı6ıul 0) - Cranfield University

Expected mean current from transient values:
,
mann - a31 max + 1'31miu
Expected background to average voltage ratio:
Vbk = a4 + 04Ij + 54SO
V. , an
Expected background voltage:
Vbk = a5 +f
where
WFS is the wire feed speed;
SO is the stand-off;
V is the set-up voltage;
mr. +6srmemi (3.5)
'mean is the average welding current;
Imin is the minimum current value in a sample;
I. is the maximum current value in a sample;
Vmean is the average welding voltage;
Vbk is the background voltage;
a1... 5,01... 3,51... 5 are regression coefficients.
b) Models for predicting bead geometry (see Figure 3.3)
Expected bead dimension (BD)
where
BD
WFS
SW
BD=a6WFSß`
Sw
is the bead dimension (Leg,, side leg length; Legb, bottom leg length);
is the wire feed speed;
is the welding travel speed;
a6 and 06 are regression
constants.
Expected weld penetration (Pen)
where
Pen=a, (l, . V.. )0.5 +07S
69
(3.3)
(3.4)
(3.6)
(3.7)