Portable Electronically Based Method for the Nondestructive Remote Sensing of Crevice Corrosion.

摘要

Corrosion in the crevices of gasketed joints in the presence of sea-water has been particularly troublesome for the Navy in pipelines. Some of the existing non-destructive techniques can be used without entering the pipeline system but most of them suffer from low signal-to-noise ratios due to spurious signals caused by scattering on rough-pitted surfaces. The main advantages of four-point probe pulsed current resistance measurements, the innovative approach described in this report, are that the sensing probe can be easily adapted for inspection of different sizes of flanges and the costs for development and application of this technique will be very low. Significant conclusions from the research included: (1) the results fully demonstrated the feasibility of using the pulsed current resistance technique for the non-destructive detection of crevice corrosion in flanges; (2) resistance measurements based on current pulsing are more sensitive than measurements made using constant DC currents; (3) the pulsed current resistance measurement technique can be easily automated and computerized, which can provide high resolution three-dimensional images of flange damage. The key research and development area for follow-on work is full development of an automated, portable, flange crevice corrosion detection system, consisting of: (1) resistance probes of appropriate size; and (2) a computerized resistance meter based on high amplitude pulsed currents/low voltage sensing system. Flanges, Gasketed joints, Crevice corrosion, Non-destructive detection, Four-point probe, Resistance measurements.