APPLICATION OF DISCRETE SPECTRUM TO ULTRASONIC FLAW INSPECTION OF HCC ROUNDS FOR PIPE-MAKING

When longitudinally detecting bulky defectives of HCC rounds, serious structural noise is produced. With the discrete spectrum technique for signal processing, the noise level will be considerably lowered, hence, increasing the signal-noise ratio. Relevant experiment result shows that it is possible to find out any defect equal to or bigger than Φ3mm flat-hole equivalent in a HCC round with the discrete spectrum technique in ultrasonic detecting process.