Page 403 - Corrosion Engineering Principles and Practice

372 C h a p t e r 9 A t m o s p h e r i c C o r r o s i o n 373

Khartoum, Egypt 1
Abisco, North Sweden 3
Singapore, Malaysia 9
Daytona Beach, Fla. (Inland) 11
State College, Pa. 25
South Bend, Pa. 29
Miraflores, Canal Zone, Panama 31
Kure Beach, N.C., 250 m. from ocean 38
Sandy Hook, N.J. 50
Kearny, N.J. 52
Vandegrift, Pa. 56
Pittsburgh, Pa. 65
Frodingham, U.K. 100
Daytona Beach, Fla., near ocean 138
Kure Beach, N.C., 25 m. from ocean 475
TABLE 9.5 Relative Atmospheric Corrosion Susceptibility of
Open-Hearth Steel

As shown in Table 9.5, it is impossible to give a corrosion rate for
steel in the atmosphere without specifying the location, composition,
and certain other factors. If one can relate exposure conditions to
those described in the literature, a fairly good estimate can be made
of the probable corrosion behavior of a selected material. However,
all aspects of the exposure of the metal surface must be considered.
A high-strength low-alloy (HSLA) steel, also called weathering
steel, may show an advantage in corrosion resistance of 12:1 over
carbon steel when freely exposed in a mild environment. This is why
weathering steel has been the choice of many designers for the
construction of boldly exposed surfaces, from buildings to utility poles
(Fig. 9.45). While weathering steel does not require any particular care
once installed, it may suffer surprising corrosion attack in crevice
areas. As the severity or the physical conditions of exposure change,
the HSLA steel will show less superiority. In crevices or on the backside
of structural forms in a corrosive atmosphere, HSLA steel will in fact
not perform better than plain carbon steel (Fig. 9.46).
Very little needs to be said about the behavior of stainless steels
(Types 200 and 300), which contain high percentages of nickel and
chromium, except that they can keep their shiny aspect without tar-
nishing for many decades, as illustrated in “The Triad,” a tall sculpture
erected in the busy part of Toronto, Canada in 1984 (Fig. 9.47). Stainless
steel has also been used to great advantage in more notorious buildings
and monuments.