D.H. Lammlein PhD Dissertation - Vanderbilt University

Figure 77: Macrosection of the weakest 90° conical weld(90°,1400rpm, 4ipm, Run#1).
Failure occurred at the jointline and along the retreating side weld nugget boundary. A
significant lack of penetration (weld root) defect can be seen in this weld indicating a
slight error in the automated zeroing process for this particular weld. Three welds at
each parameter set were performed to distinguish such outliers.
Figure 78: A particularly revealing macrosection (90°,1400rpm, 5ipm, Run#1). A
jointline remnant can be seen curving through the weld nugget center. In addition, the
lack of consolidation near the cone tip which is typical of a cone weld can be seen clearly
here. The lack of sufficient probe surface area, heating, and pressure at the cone tip
result in a lack of consolidation there.
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