Effect of Selecting Immersion Probes on Back-wall Echo Monitor of 1Cr21Ni5Ti Steel Bars

In order to discuss the factors of immersion probes impact on the back-wall echo monitor of 1Cr21Ni5Ti stainless steel bars, different frequency or types of focus probes and different water paths settings were usd. Also, LS200B type equipment was employed for the ultrasonic test of the bars.Then, the PROCESS image evaluation software was utilized to analyze the C-scan images. The results show that the back-wall echo amplitude of 1Cr21Ni5Ti bars circumferential direction is varied. The probe frequency, focus type and water paths will affect the amplitude level of the back-wall echo.