Research on Defects Examination and Crack Assessment for Cast Iron Dryer

The strength and hardness tests to the experiment dryer were carried on, from the relation of strength and hardness, the relative hardness RH is 0.8 according to ‘principle met using’. The velocity of sound should be measured first in the thickness measurement, the ‘false’ thickness phenomenon in dryer flange and the convex transition segment were discovered. The ultrasonic examination characteristics of the cast iron dryer was analyzed, the sensitivity of various sensors were carried on. The small angle double crystal longitudinal wave sensor can examine the Φ3 equivalent diameters of the volume defects, and the big angle double crystal longitudinal wave sensor can examine 2 mm deep surface crack of the body and the transition area. The safety assessment on 2 mm deep surface crack was carried on.