Ultrasonic flaw detecting method for stainless steel coated tube

Abstract

Abstract PURPOSE:To increase an SN ratio by using an ultrasonic flaw detector and an ultrasonic probe which have 5-15MHz wide-band frequency characteristics. CONSTITUTION:A coated tube 2 while rotated on its axis is sent axially, and a lateral wave ultrasonic beam is transmitted by the ultrasonic probe 4 and its reflection echo is received. In this case, the ultrasonic flaw detector 5 uses a detector which has 5-15MHz wide band frequency characteristics. Therefore, a high frequency component is attenuated in a member and a low frequency component remains, so a defect echo is obtained highly and the SN ratio is improved. Further, the probe 4 uses a probe having 5-15MHz wide band frequency characteristics as well as the flaw detector 5. When frequency characteristics has a wide band, the pulse width is narrow, so a grove-shaped echo received by the probe 4 within a time interval is reduced and the probe 4 can be arranged so that the grove-shaped echo is not received as much as possible. Thus, the SN ratio is improved.

Inventors

• 👤 Noritsugu Fujii
• 👤 藤井　教嗣

Bibliographic Details