Effect of velocity on current density for cathodically polarized steel in seawater

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Corrosion

DOI:https://doi.org/10.5006/1.3283972· OSTI ID:315921

Hugus, D; Hartt, W H ^[1]

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1. Florida Atlantic Univ., Boca Raton, FL (United States)

A series of cathodic polarization experiments was performed in which sections of UNS G10230 steel pipe were galvanically coupled through an external resistor to an aluminum anode ring. These cells were incorporated into a seawater flow loop such that the hydrodynamic conditions were defined quantitatively. Seawater velocities for the experiments were 0.03, 0.09, and 0.30 m/s. From the results, the trend of steady-state potential vs current density at a given velocity was characterized in terms of the recently proposed slope parameter approach to cathodic protection (CP) design. Also, an expression for the velocity dependence of the maintenance current density was developed. Anomalous behavior was encountered for some specimens tested at velocities of 0.09 m/s and 0.30 m/s in that these exhibited a period of depolarization followed, in some cases, by repolarization. This behavior was reviewed in terms of transitory calcareous deposit protectiveness, possibly reflecting the relative amounts of calcium and magnesium in the deposits at a particular time.

• Sponsoring Organization: USDOE
• OSTI ID: 315921
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 2 Vol. 55; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
CATHODIC PROTECTION
DEPOSITS
DESIGN
OFFSHORE OPERATIONS
SEAWATER
STEELS
VELOCITY