Ultrasonic Testing using a Combination of Logarithmic and Linear Amplifiers

An ultrasonic imaging system using a combination of logarithmic and linear amplifiers has been developed. The new system links the two amplifiers effectively to image the crack opening, crack tip, inner configuration of the pipe joint and the weld metal to base-metal interface configuration. The reconstructed image helps an ultrasonic operator to identify crack echoes from geometrical echoes in flaw detection, and to identify the crack tips for crack depth sizing. This paper discusses the use of two amplifiers of different character and reports that there is a suitable combination of amplifiers. The effectiveness of the system is verified through the ultrasonic imaging of stress corrosion cracking in a stainless steel pipe weld.