LIBRARY ı6ıul 0) - Cranfield University

Table 7.2 - Bead geometry along the welds produced in the non-controlled flat
nncitinn fillet welding trials
Run Measured feature Position alon the weld mm Geometry feature
mm 30 65 100 135 170 Min. Required Expected
2 Leg., 4.90 4.79 4.46 4.72 4.47 4.00 4.46
Pen.,, 0.78 0.69 0.63 0.54 0.46 0.32 0.60
Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0
3 Le 6.13 6.25 5.98 5.80 5.73 6.00 6.41
Pen,. 0.99 0.87 0.85 0.78 0.81 0.32 1.26
Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0
M4 Le 4.39 4.05 4.31 4.68 4.06 4.00 4.54
Pen,,, 1.09 1.19 1.17 1.06 1.10 0.32 1.26
Max. Undercut 0.28 0.55 0.37 0.37 0.48 0.0 0.0
5 Le 4.61 4.68 5.03 4.74 4.97 5.00 5.40
Pen,,, 2.04 1.86 1.74 1.57 1.47 0.32 1.70
Max. Undercut 0.30 0.32 0.21 0.30 0.30 0.0 0.0
6 Le-gW 5.08 5.21 5.14 4.93 5.03 5.00 5.43
Pen, 1.78 1.70 1.67 1.57 1.59 0.32 1.86
Max. Undercut 0.21 0.11 0.18 0.32 0.32 0.0 0.0
7.3 Tests with only stand-off control
Some tests using only stand-off control were carried out with the same
welding parameters as shown in Table 7.1. The welding trials were referenced as "Sn"
(n--2,..., 6) and the resulting bead appearances
and bead profiles are shown in Figures
7.15,7.17,7.19 and 7.21. Figures 7.16,7.18,7.20 and 7.22 show the variation of the
mean welding voltage and current as well as the stand-off along the welds. The stand-
off was maintained within -1.0 mm and 2.5 mm from the required stand-off for all the
welds. The resulting weld beads did not present any significant differences in
appearance from the non-controlled trials. However a more consistent penetration
depth was obtained along the weld beads. Table 7.3 shows the geometry features
measured along the welds produced in the stand-off controlled welding trials.
The same defects observed in the non-controlled spray transfer welding trials
were observed to occur in the stand-off controlled ones. One difference observed,
however, was that the defects occurred with the same intensity through-out the weld
beads, while in the non-controlled trials a reduction in the level of defects was
observed towards the end of the welds. This difference was possibly caused by the
fact that the stand-off was kept almost constant in the controlled trials whereas in the
case of the non-controlled trials the increase in stand-off reduced the damaging effect
of the excessive set-up welding voltage. Also, the finger-like penetration profile was
observed to occur.
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