75 years of Egokiefer: Tradition and Innovation

Surface Technology
is matched to the base material. Hard chromium coatings can
be ground and polished to a mirror finish. Due to the hardness
and homogeneous structure of the coating, surface
finish qualities are achieved that are not possible with other
coatings. STI | Hartchrom realises high-gloss surface finishes
with a roughness in the micro range on rolls with a surface
area of several square metres. Hard chromium coatings are
generally cheaper than other coating processes, particularly
for large parts. However, there are some cases in which the
combination of coating and mechanical finishing thermally
sprayed HVOF coatings can be interesting in terms of cost.
Calender rolls: hard chromium coatings have priority
particularly in high-end applications. Case 1: a paper mill
changed the calender rolls on a large paper machine from
hard chromium to another type of coating due to the greater
resistance to wear outside the production web. In view of the
massive corrosion problems, however, the mill changed back
to hard chromium coating again. Case 2: in the HVOF (High
Velocity Oxygen Fuel thermal spraying) process, thermally
sprayed layers permit a larger variety of ductors than hard
chromium coatings. However, a hard chromium coating with
matched ductor remains constantly smooth during usage, or
becomes even smoother.
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Top class
«Innovation is the basis
for success.»
New markets, new products
STI | Hartchrom is continuously expanding its range of services
for its customers. In accordance with the motto «We surface
your visions», STI | Hartchrom provides individual complete
solutions and a large range of innovative processes and coatings.
Along with hard chromium plating and textured chromium
plating, STI | Hartchrom is covering a wide range of
new applications and possibilities to the usual excellent STI
quality with its adoption of thermal spraying (HVOF) and
chromium-ceramic coatings (deposition of ceramic in hard
chromium coatings). «
Piston crowns, piston rings for engines: a hard chromium
plating optimised for piston grooves combines very good
wear properties with good lubrication due to deposited «oil
pockets». Maximum protection against wear for piston rings
and increased thermal hardness of the coating is provided by
a new chromium-ceramic coating.
Gun barrels: due to the particularly high adhesive strength,
the durability of the coating, the protection against erosion
and the thermal protection action, hard chromium coatings
are unequalled for gun barrels. In the past, massive efforts
were made to replace hard chromium with other coatings.
However, the other coatings did not withstand the high
mechanical and thermal loads.