THE EFFECTS OF ULTRASONIC INSPECTION TECHNIQUES ON SIGNAL-TO-NOISE RATIO OF Ti-17 TITANIUM ALLOY ROUND BILLET 350 MM IN NOMINAL DIAMETER

摘要

Experiments using inspection system manufactured by GE, and a Ti-17 billet 350mm processing a reference block. Machining three sizes of FBHs were 1.2,2.0 and 3.2mm, with metal distances from 5 to 188 mm, divided into seven zones. Respectively by contact, conventional and multi-zone immersion to test the billet The focal depths in billet of multi-zone transducers were from 13 to 175 mm. The results showed that The signal-to-noise ratio of contact is Φ3.2-18dB, the operation is convenient and economy, but its sensitivity is relatively low. The S/N ratio of conventional immersion is Φ2.0-18dB, it has good reliability and high efficiency. The S/N ratio of multi-zone immersion is Φ1.2-14.5dB, and the efficiency is relatively low but it has high detection sensitivity with smaller defects. In order to ensure the quality of Ti-17 billet, should be prefer multi-zone immersion technique.