Evaluation of bar for critical applications using ultrasonics

Ultrasonic Testing is carried out on bars of special steels, titanium alloy etc. in Nuclear Fuel Complex using longitudinal and shear waves. Flat bottomed holes or side drilled holes are used as reference standards for normal beam testing, while notches are used for angle beam testing. For normal beam testing DAC is made with the help of flat bottomed holes drilled to different depths. Whenever any indication comes tube movement is to be stopped for comparing with DAC. With the selection of right frequency probe and right focussing equalization of the flaw echoes can be achieved over a limited metal path distance and then the evaluation of flaw does not require stationary comparison. For angle beam testing of bars rectangular notches are found to be more adequate for detecting surface cracks than V-notches. (author)