Digital radiography and Computed radiography for Enhancing the Quality and Productivity of Weldments in Boiler components
This paper presents a detailed performance analysis and comparison of Conventional film radiography, Real Time Radioscopy with Digital Radiography (DR) using Flat Panel and Computed Radiography (CR) using Flexible Phosphor Imaging Plates, in the case of Quality evaluation of weldments in Boiler Components. Conventional Film Radiography is a slow, expensive and hazardous method, particularly for mass production. Eventhough Real Time Radioscopy (RTR) with Image Intensifiers is an alternative to film radiography, conventional RTR systems are compared unfavorably with film radiography in two aspects viz.low contrast sensitivity and limited resolution.The new digital detector arrays (Flat Panel Detector) have the potential to substitute the X-Ray films as they have considerably higher image quality than the conventional Image Intensifiers. They allow fast acquisition of radiography images with high dynamic range, and high signal to noise ratio.Computed Radiography is one of the Digital Radiographic Techniques used in lieu of conventional film radiography. The Phosphor Imaging plates (IP) are used as digital detectors in place of photographic X-Ray films.The experimental results revealed that DR can successfully replace Real Time Radioscopy with X-Rays and Image Intensifier, for Tubular Steel welds up to Single wall thickness 12mm. Using the Flat Panels with 200 microns pixel pitch, it was possible to achieve more than 3 line pairs / mm, at an MTF of over 20%. On the other hand CR has been found to be suitable for Radiography of thick wall welds (Steel thickness up to 140 mm) in Boiler components using Gamma Ray Isotopic Sources like Ir-192, Co-60 and X-Ray sources including Linear Accelerators (up to 6 MeV) with spatial resolution better than 25mico meter, meeting the 2 % Radiographic sensitivity requirements as per ASME code.
Real Time Radioscopy (RTR) Digital Radiography (DR) Computed Radiography (CR) Weldments in Boiler Components Quality evaluation
R.J. PARDIKAR
SDGM / NDT, BHEL, Tiruchirappalli,Tamilnadu-620014.
国际会议
第十七届世界无损检测会议(17th World Conference on Nondestructive Testing)
上海
英文
3547-3554
2008-10-25（万方平台首次上网日期，不代表论文的发表时间）