Nace CP 1, Course Manual

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NACE GLOSSARY OF CORROSION-RELATED TERMS
©
2002, NACE International. This publication may not be reprinted without the written consent of NACE International.
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insignificant.
RESISTIVITY
(1) The resistance per unit length
of a substance with uniform cross
section. (2) A measure of the
ability of an electrolyte (e.g., soil)
to resist the flow of electric
charge (e.g., cathodic protection
current). Resistivity data are
used to design a groundbed for a
cathodic protection system.
REST POTENTIAL
[See Corrosion Potential. ]
REVERSIBLE POTENTIAL
[See Equilibrium Potential. ]
RIMMED STEEL
An incompletely deoxidized steel.
[Also called
Rimming Steel .]
RISER
(1) That section of pipeline
extending from the ocean floor
up to an offshore platform. (2)
The vertical tube in a steam
generator convection bank that
circulates water and steam
upward.
RUST
Corrosion product consisting of
various iron oxides and hydrated
iron oxides. (This term properly
applies only to iron and ferrous
alloys.)
RUST BLOOM
Discoloration indicating the
beginning of rusting.
S
SACKING
Scrubbing a mixture of a cement
mortar over the concrete surface
using a cement sack, gunny
sack, or sponge rubber float.
SACRIFICIAL ANODE
[See Galvanic Anode. ]
SACRIFICIAL
PROTECTION
Reduction of corrosion of a metal
in an electrolyte by galvanically
coupling it to a more anodic
metal (a form of cathodic
protection).
SCALING
(1) The formation at high
temperatures of thick corrosion-
product layers on a metal
surface. (2) The deposition of
water-insoluble constituents on a
metal surface.
SCANNING ELECTRON
MICROSCOPE
An electron optical device that
images topographical details with
maximum contrast and depth of
field by the detection,
amplification, and display of
secondary electrons.
SENSITIZING HEAT
TREATMENT
A heat treatment, whether
accidental, intentional, or
incidental (as during welding),
that causes precipitation of
constituents (usually carbides) at
grain boundaries, often causing
the alloy to become susceptible
to intergranular corrosion or
intergranular stress corrosion
cracking.
SHALLOW GROUNDBED
One or more anodes installed
either vertically or horizontally at
a nominal depth of less than 15
m (50 ft) for the purpose of
supplying cathodic protection.
SHIELDING
(1) Protecting; protective cover
against mechanical damage. (2)
Preventing or diverting cathodic
protection current from its natural
path.
SHOP COAT
One or more coats applied in a
shop or plant prior to shipment to
the site of erection or fabrication.
SHOT BLASTING
Abrasive blast cleaning using
metallic (usually steel) shot as
the abrasive.
SHOT PEENING
Inducing compressive stresses in
the surface layer of a material by
bombarding it with a selected
medium (usually steel shot)
under controlled conditions.
SIGMA PHASE
An extremely brittle Fe-Cr phase
that can form at elevated
temperatures in Fe-Cr-Ni and Ni-
Cr-Fe alloys.
SLIP
A deformation process involving
shear motion of a specific set of
crystallographic planes.
SLOW STRAIN RATE
TECHNIQUE
An experimental technique for
evaluating susceptibility to
environmental cracking. It
involves pulling the specimen to
failure in uniaxial tension at a
controlled slow strain rate while
the specimen is in the test
environment and examining the
specimen for evidence of
environmental cracking.
SLUSHING COMPOUND
Oil or grease coatings used to