Examples of Failing Welds: Sample #1 (Destructive Testing) Cold Welds Hot Welds Failure was as the weld Poor fusion of the filler rod / wire to the tubes Weld bead radius is smaller than tube wall thickness Little to no heat discoloration The fitted / coped edges of the tube are visible after separation Failure was at the weld Weld / tube thickness was very small at point of failure Weld bead radius is distinctly larger than tube wall thickness Extreme heat discoloration

Examples of Failing Welds: Sample #2 (Destructive Inspection) Inconsistent and unclearly defined fusion line Weld bead radius is smaller than tube wall thickness Weld bead does not adequately contact and fuse the both tubes 1

Sample #1 – Destructive Testing Sample #2 – Destructive Inspections Examples of Passing Welds Sample #1 – Destructive Testing Sample #2 – Destructive Inspections Moderate Heat Discoloration Weld bead radius is approximately the same as tube wall thickness Clearly defined and substantially uniform width fusion line, no burn - through Failure was not at the weld Weld bead radius is approximately the same as tube wall thickness Moderate Heat Discoloration 2