EVALUATION OF ULTRASONIC TEST INDICATIONS OF CREEP DAMAGES IN HIGH TEMPERATURE PRESSURE PARTS OF POWER PLANTS

NDTnet

WCNDT '96 - New Delhi
Table of Contents

Ultrasonic Testing - Microstructure and Material Degradation

EVALUATION OF ULTRASONIC TEST INDICATIONS OF CREEP DAMAGES IN HIGH TEMPERATURE PRESSURE PARTS OF POWER PLANTS

V. Krishnamurthy, G. Venkataraman and R. S. Babu
Welding Research Institute, Bharact Heavy Electricals Limited
Tiruchirappalli - 620 014, India

Keywords: Ultrasonic, creep, material degradation, in-situ characterization, power plant

ABSTRACT

It is well know that high temperature components working in the creep range undergo material degradation to a noticeable extent after the designed life. In some instances the damage occurs in the form of creep pores and grain boundary creep cracks as a result of dislocation interactions. The intrinsic micro defects such as creep pores in localized regions attenuate ultrasonic sound waves. The attenuation pattern of indications from different stages of crept materials followed a pattern which enabled to obtain a correlation between the observed pattern and the severity of creep damage. The attenuation of multiple echoes from the conventional normal and angle beam probes of different frequencies bears a comparison to that of attenuation techniques and velocity measurements. This approach enables in-situ characterization of components. A comparative damage evaluation of serviced plant components by metallography agrees fairly well with the ultrasonic evaluation.

Ultrasonic Testing - Microstructure and Material Degradation

Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 4, pages 2225 - 2230
Publisher: Ashgate Publishing Company