ALL ABOUT TEMP-PLATE® - Paul Mueller Company

Factors Affecting Corrosion
Some of the factors that influence corrosion, other than
the composition of the metal and corrodent itself, are as
follows:
1. The presence of impurities in the corrosive medium.
Inasmuch as pure chemicals or solutions are seldom
encountered in commercial work, the presence of
even minor percentages of impurities is of most
importance and should be considered when using
published corrosion tables.
2. The temperature of the corrodent. As a rule, the degree
of corrosion increases with increase in temperature.
There are numerous cases where metals satisfactory for
cold solutions are entirely unsuitable for these same
solutions at more elevated temperatures.
3. The degree of aeration to which a corrodent is
exposed. Liquids kept in closed containers from
which air or a circulation of air is excluded will cause
different degrees of corrosion than these same liquids
when freely exposed to the atmosphere. This applies
also to the presence of atmospheric gases which may
sometimes change the corrosive behavior of metals
to a marked degree.
4. Velocity of corrodent. Since published corrosion
tables are usually based on static tests, the corrosion
actual service may differ due to the effect of the
velocity.
THE PROBLEMS OF CORROSION
Importance of Passivating
The corrosive-resistant qualities of stainless steels are
inherent in the metal itself. However, the contamination
of the surface by adhering dirt or scale will have a
deleterious effect. For this reason, it is essential that all
scale be completely removed and the parts be kept clean
while in service.
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