Crack growth monitoring on industrial plant using established electrical resistance ‘scanner’ technology

Abstract

DC electrical resistance techniques (potential drop methods) are well-established methods for detecting both corrosion and crack growth during laboratory-based experiments. However, application of the techniques to large industrial plant has, to date, been somewhat limited. Rowan Technologies has, over the past nine years, been developing and refining its scanner technology to monitor corrosion/erosion, thermal parameters and more recently crack initiation and propagation on an EPRI-sponsored project. Crack monitoring is achieved by welding matrices of electrodes to the external (air-side) metal surfaces, from which a number of high-precision measurements are made to detect and quantify changes in electrical resistance associated with crack growth. Extensive laboratory-based work preceded a full-scale trial of the scanner on an 830MW supercritical boiler in the USA, where circumferential cracking of weld overlaid boiler tubes is of major concern. This paper discusses the background to the technique, reports on the laboratory-based results of simulated crack growth and also gives initial results from the boiler trial.

Inspection and monitoring systems subsea pipelines: A review paper

“…Thus, a larger drop in electrical potential does not necessarily correlate to the size of damage since the path of current may simply be altered. Some efforts, such as electrode placement optimization 57,65 and current distribution calculations, 66 have been reported to combat such drawbacks. Recent work in this field has proposed both the use of a large database to match current distribution patterns to certain types of damage 67 and improvements to the mathematical modeling of damage-induced current redistribution.…”

Improved formula for localized corrosion using field signature method

“…For general corrosion, the degree of corrosion occurred in the entire metal surface is the same, therefore the current distribution will not changed. However, for localized corrosion, the extent of corrosion in various parts of the measured pipe is inconsistent, therefore the current field in the measured pipe will be changed [20,21]. Therefore Eq.…”

Detection of Cracks in Clay Soil Using Quasi-3D Electrical Resistivity Tomography Method: Numerical and Experimental Study

“…It provides non-invasive 2D/3D resistivity sections, at laboratory and field scales, that have been used at the early stages to map fractures and faults [6,7,8]. For detecting small scale cracks, electrical resistivity method has proven successful in identifying cracks in metals [9], and concrete [10]. In soil science, laboratory experiments were conducted to characterize cracking of clay soils.…”