the Finnish Maritime Administration and
through it for shipyards and industries
that use seawater in cooling systems.
Under the late Professor Seppo Yläsaari,
the laboratory played a decisive role in
transferring know-how to practical applications in Finland concerning cathodic corrosion prevention systems with
external power sources used on ships.
The systems are now used in a large par t
of ships and in industrial seawater pipelines and por t structures. We have also
trained staff at the Maritime Administration and various companies in corrosion
prevention techniques,” Aromaa says.
“Our expertise also covers industrial and marine seawater pipelines and
their heat exchangers, and corrosion prevention and protection. We have studied the use of corrosion inhibitors in
several different systems. We have studied the use of different organic and inorganic coatings to protect structures in
various circumstances.”
Hot galvanisation
provides good protection
against corrosion
In marine corrosion protection, hot galvanisation has established itself as one of the
principal protection methods.YIT Industria
Oy has manufactured and coated pipelines
and pipe modules since 1976.The method
involves the hot galvanisation of pipes after
manufacture so that the coating is uniform
on both the outside and the inside. Some
30% of the pipes on a ship – mainly water
and air pipelines – are hot galvanised. Coating is also used as corrosion protection for
railings, stairs and hatches, for example,
where the coating is covered with paint for
even better protection.
Zinc is a common coating material
also on oil drilling platforms, where underwater structures are generally not painted.
They receive additional protection from
cathodic anodes, of which there may be
hundreds of tonnes on a big platform.
Rubber cures pipeline corrosion
“Pipeline corrosion on cruise ships is largely the result of difficult conditions: the ships
take their water from the sea and often
ports surrounded by coral reefs, where the
water contains coral sand which erodes
pipelines,” explains director Hannu
Vesterinen from Kumijaloste Oy.
“Rubberisation has proved to be a
very good solution.There are various materials available to suit different needs,
such as for ships handling oil. Moreover,
rubberisation does not increase fire load
in areas where fire safety is critical.”
”Rubberisation is usually done after the pipeline has been welded together. A raw rubber film of roughly
4mm is spread at a temperature of
about 140º centigrade by vulcanising
so that it is fixed tightly to the interior
surface of the pipeline. Its adhesion
strength is higher than the tensile
strength of rubber.”
SEATEC 2005 41