Development of an Automated - Ultrasonic Gauging System for Tubes and Pipes

Tubes/Pipes employed in critical applications such as Power Plants, Petrochemical industry and others, demand very stringent quality control. Various Non-Destructive Testing (NDT) techniques are used for inspection of such objects both during fabrication as well as in-service stages. Ultrasonic testing (UT) is a very popular NDT technique adopted in such applications. Flaw detection and thickness gauging are the main UT methodologies adopted in such inspections. Today, ultrasonic imaging systems are also available and such a system can be utilized for complete volumetric inspection of the desired tubes/pipes. In flaw detection, the prime objective is detection of internal flaws, if any, where as gauging enables high resolution thickness and dimension measurements. Imaging systems basically provide both the operations, though gauging using imaging technique may not provide very high resolution. An advanced system capable of both, B/C-Scan imaging and high resolution gauging of tubes/pipes has been developed at Electronics Division, B.A.R.C. The system is based around an Industrial Personal Computer and all the electronics hardware needed for imaging and gauging has been developed at B.A.R.C. Extensive application software – based on Visual Basic and Visual C++, running under Windows98 – has been developed to provide realize an advanced system suitable for tube/pipe inspection and gauging. A two axes motorized mechanical scanner has been fabricated and it provides automated inspection of tubes from inside using water immersion technique, under the control of host PC. Initial trials have been carried out using Zircaloy and Stainless Steel sample tubes with artificial defects. This paper highlights the hardware and software features of the ultrasonic system and includes a discussion on the trial inspections carried out with the system.