Page 333 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

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impairment of fit or function. Corrosion control shall be achieved by a combination
of design features, materials selection such as composites, galvanized steel, E-coat,
coil coating, production techniques, process controls, inspection, and documentation.
The minimum requirement is galvanizing of ferrous components in accordance with
the galvanizing policy, appropriate pretreatment, and E-coat primer. Subsequent use
of rust-proofing materials, such as MIL-C-46164, is not a substitute for any of these
minimum requirements.
The MTVs of the first batch did not meet the corrosion protection requirements.
Corrosion on the cabs was found in 3 years although the contract specified that cor-
rosion of the vehicles should not occur for 10 years. Rather than replacing the MTVs,
damage was repaired to give a life of 10 years free from corrosion.
The army subjected one of the 4995 trucks to corrosion tests. The corrosion dam-
age occurred in 60 areas, and the procedures were modified, and about 3751 trucks
were produced with galvanized steel cabs.
Corrosion also occurs in Howitzer firing platforms. Severe galvanic corrosion
because of dissimilar contact in the areas on the platform took place where water
could collect. The total cost of the remedy of the corrosion problem is estimated to
be nearly $9 million. Another corrosion problem experienced with the towed M198
Howitzer can be solved by drilling a drain hole at the lowest point.
Nearly 8–22% of overhaul and repair costs of helicopters are because of corrosion.
In 1998, nearly 44 billion was spent on corrosion control of helicopters.

4.34.2 Navy
The fleet consists of ships, submarines, aircraft weapons, and facilities, and the total
cost of corrosion is estimated to be $2 billion/year.
The surfaces of ships are exposed to extremely aggressive environments. An
extensive corrosion control program is required to maintain the fleet during dry-dock
cycles. The primary defense against corrosion is the diligent use of protective
coatings. In addition to coatings, CP is used for protection of the underwater hull.
The cost of CP is lower than coatings. The traditional coatings have a design life of
10–15 years after which the old coating is removed and a new coating is applied.
Between major maintenance cycles, there is an annual maintenance demand for
continuous coating maintenance.
Table 4.51 lists the annual coating maintenance of Navy surface ships.
One of the major tools to prevent corrosion on naval aircraft is painting. During
the period from August 1995 through 1996, 341% more paint than necessary was
used for the prevention and control of corrosion damage of the F-18 aircraft and F-14
squadrons, by painting large sections of their aircraft every 56 days.

4.34.3 Air Force

The total cost of direct corrosion maintenance to the Air Force for 1997 was estimated
at nearly $800 million. The majority of the cost can be attributed to repair ($573
million) and paint ($146 million). Corrosion maintenance consists of inspection for