The best and the logical solution to protect the steel materials
against corrosion is coating it with the hot-dip galvanizing
method.
Steel materials are corroded by loosing their physical, chemical,
electrical and other characteristics affecting from the atmospheric
conditions where they are. Those changes are summarized as
“rusting”. Rusting is not only a visual defect but also a
chemical reaction which negatively affects the metal. Also,
as rust has about thirty times the volume of steel, rusty
metal tends to destroy its environment. Therefore, the surface
of steel structures should be treated with protective methods
to get rid of the corrosive effects of the environment. Some
examples of protective methods are painting and coating with
plastics, nickel, chrome, copper and zinc. However, among
all the methods, hot-dip galvanizing is the most reliable
and long lasting coating method.
Hot-dip galvanizing features following advantages against
other surface treatment methods:
-
Buildup of a thick, penetrating and homogenous surface
film even in critical spots like interiours, sharp edeges,
cutting edges, bore surfaces, cavities, difficult to
approach with other methods.
-
All
other methods are sensitive to surface damage like minor
scratches as corrosion will start from these areas and
will peel away the surface film. However, hot-dip galvanizing
is resistant to scratching and has “self healing” properties.
These properties can be summarized as “cathodic protection”.By
the same token, hot-dip galvanized surfaces are resistant
agains shocks like hammer blows.
-
Zinc will form a metallurgical bond with the ferrous
substrate and the alloy formed at the surface will increase
the surface resistance to external influences.
-
Within all surface treatment films, galvanizing is the
most long lasting treatment and does not require any
maintenance.
-
Hot-dip galvanized surfaces display a certain visual
appeal. Freshly galvanized surfaces show up a shiny
and two dimensionally chyrstalline sturcture, later
the surface assumes a homogenous dull gray appearance.
-
Hot-dip galvanizing is an economical treatment of ferrous
metals.
However,
hot-dip galvanizing has also certain disadvantages:
-
No
repairs and modifications are possible with hot-dip
galvanized structures. Any changes require the process
to be repeated.
-
Preferably, all members have to be galvanized separately,
thus, an assembly has to be disassembled, galvanized
and the reassembled and rebedded as required.
-
Some structures, like tanks with small openings are
not suitable for hot-dip galvanizing. The designer has
to know beforehand, that the upcoming structure will
be subjected to hot-dip galvanizing.
-
The
hot-dip galvanizing plant is an expensive and not very
common investment, the logistics of the process may
be difficult.
On
most yachts chains and anchors are hot-dip galvanized. Specially
classic yachts display hot dip galvanized anchor fittings,
chain plates, fairleads, gooseneck and masttop fittings and
a number of other structures.
YachtWORKS,
recommends and performs hot-dip galvanizing according to TS-914
and DIN 50976 standards. Please contact us for quotes and
for schedules. |
