The effect of velocity upon maintenance current density for cathodically polarized steel in sea water

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:352568

Hugus, D; Hartt, W H ^[1]

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1. Florida Atlantic Univ., Boca Raton, FL (United States). Dept. of Ocean Engineering

A series of cathodic polarization experiments was performed in which sections of UNS G10230 steel pipe were galvanically coupled through an external resistor to aluminum anode rings. These cells were incorporated into a sea water flow loop such that the hydrodynamic conditions were quantitatively defined. Sea water velocity for the experiments was 0.03, 0.09, and 0.30 m/s. From the results, the steady-state potential versus current density trend at a given velocity was characterized in terms of the recently proposed slope parameter approach to cathodic protection 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 and 0.30 m/s in that these exhibited a period of depolarization followed, in some cases, by repolarization. This behavior is discussed in terms of transitory calcareous deposit protectiveness, possibly reflecting the relative amounts of Ca and Mg in the deposits at a particular time.

• OSTI ID: 352568
• Report Number(s): CONF-980316--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
ANODES
CATHODIC PROTECTION
CURRENT DENSITY
ELECTRIC POTENTIAL
FOULING
SEAWATER
STEELS
VELOCITY