Posted by Gordon England on July 16, 2003 at 19:16:44:
In Reply to: mystery material removal posted by Jennifer Weinbrecht on July 15, 2003 at 15:12:18:
: Has anyone ever had a situation where multiple passes (unintentional - apparently due to turntable failing) resulted in a band of missing material of the substrate, discovered after stripping? The band of missing material is about 0.002 inch lower than surrounding substrate where multiple passes did not occur. There was only one pre-heat pass. Not sure when turntable stopped during 12 passes. Tungsten Carbide on Mirage 250, air plasma spray. Very strange.
Hi Jennifer
Yes, very strange. I would be inclined first to check that the original dimensions were in fact correct. Check that the grit blasting prior to spraying was ok ( area being over blasted ). Check that the material was not removed during coating stripping. I can't see the plasma spraying having anything to do with this, particularly as the area is not associated with the excessive coating build-up. Could component distortion from localised overheating be confused with material loss?
Hope this helps
Regards Gordon
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