PRCI PR-198-808

L51613e

C.W. Pope & Associates

Need: Stress corrosion cracking poses a serious threat to aging underground cathodically protected gas pipelines. As coatings deteriorate, local conditions conducive to corrosion and stress corrosion cracking become more common. During the last decade: there havebeen several ruptures in various places throughout the world attributed to SCC. One of the most important steps in combatting failure by stress corrosion cracking is to perform regular, reliable and cost effective monitoring of the pipelines. Current methods available including hydrotesting and MPI are expensive, time consuming, not conducive to regular testing and are not entirely reliable. Regular testing of pipes will improve understanding of stress corrosion cracking, initiation propagation and tolerance.

Benefit: This report describes the present state of development of the ultrasonic pipe inspection vehicle being jointly developed by C.W. Pope and Associates and the Centre for Industrial Control Sciences at the University of Newcastle, Australia. The present aim is the evaluation of unpressurised pipelines to record areas of stress corrosion cracking (SCC) at relatively low cost and with minimum sophistication.The report addresses the suitability of ultrasonics in detecting stress corrosion cracking, outlines the system developed to date, and presents results and discussion from the laboratory trials in which the vehicle has been run in four samples of pipeline containing SCC.

Result: The prototype version of the detection system has been successfully developed for the laboratory trials detailed in this report. The system is reliably detecting and reporting the presence of modest SCC activity in pipe samples.

Product Details

Published:

09/06/1989

Number of Pages:

66

File Size:

1 file , 4.9 MB