C O R R O S I O N P R E V ENT I O N T E CHNI Q UE S Flashcards
The most common method of preventing
corrosion is the
selection of proper metal
or alloy
Not stainless; Not the most
corrosion-resistant material
stainless steel
t is a generic name for a
series of more than 30
different alloys containg 11.5
to 30% chromium and 0 to
22% nickel, together with
other alloy addition.
stainless steel
Stainless steel have widespread applications in resisting
corrosion but it should be remembered that
____________
they do not resist all corrosives.
stainless steel are
less resistant than ordinary structural steel:
Chloride-containing medium
Stressed structures
also more susceptible
to localized corrosion than ordinary
structural steels
Stainless steel
Frequently, the quality of stainless steel is checked
with a magnet
__________ stainless steels represent good alloys
and stainless steels that are magnetic are inferior
nonmagnetic
There is ___________ between magnetic
susceptibility and corrosion resistance
no correlation
A large number of corrosion failures
can be directly attributed in the
Indiscriminate selection of stainless steels
The corrosion resistance of a_________is
usually better than that of one containing
impurities or small amounts of other
elements
pure metal
are usually
expensive and relatively soft and weak
pure metals
Not expensive in a fairly pure
state - 99.5% plus.
Used for handling hydrogen
peroxide
Aluminum
More corrosion-resistant
than induction-melted
zirconium.
Used in atomic-energy
application.
ARC-MELTED ZIRCONIUM
This category involves integral or solid
nonmetallic construction and also sheet
linings or coverings of substantial
thickness
Nonmetallics
The five general classes of nonmetallics
are
rubbers, natural, and synthetic;
plastics;
ceramics;
carbon and graphite;
and wood.
Compared with metals and
alloys: weaker, softer, and
more resistant to chloride
ions but less resistant to
strong sulfuric acid and
oxidizing acids.
rubbers and plastics
Has excellent corrosion and
high-temperature resistance.
Brittle and has lower tensile
strength.
ceramics
Good corrosion resistance,
electric and heat conductivity
Fragile
carbon
frequently as
important as the choice of materials of
construction.
design of a structure
Design should consider ________ together with an _____ for corrosion
mechanical and strength requirement, allowance
Corrosion is a penetrating action. Hence, it is
necessary to make allowances for the reduction of _________ n designing pipes, tanks, and other
components that can corrode
thickness
is usually made twice the
thickness that would give the desired life.
Wall thickness
Wall thickness must meet the mechanical
requirements such as
pressure, weight, and stress
considerations