The cracks of parts were confirmed by Scanning electron microscope test (SEM). All surfaces were scanned and two areas were captured. No any crack was found on suspected articles (Pic no 4-Ltl. However it was observed unsmooths surface on the suspected article but could not find on normal article (Pic no.10-11). lt would be possible that the unsmooth surface
might reflect the light from optical microscope and looks like crack in surface.