Damage
to the shaft end is a direct consequence of bearing damage.
Shafts are still frequently repaired using the "cold" technique
in which a new layer of metal is applied at a temperature
below 300 °C. The disadvantage of this method is
that machined surfaces such as keyways and threads cannot
be treated. The applied layer would be detached at the
slightest impact and during balancing.
TurboNed,
in co-operation with Castolin, has developed a technique
in which a sprayed-on layer is fused into the underlying
material at high temperature (approximately 1150 °C).
The most important advantage of this new technique is that
it is now even possible to produce a new keyway and thread.
The
new thread will have the same tensile strength as the original
material while the shaft can be balanced on the newly applied
layer without any risk of damage. The quality of the sprayed-on
layer is very sensitive to the conditions under which it
is applied, the nature of the surface and its roughness.
By connecting the spraying unit directly with the blasting
booth, a grease-free environment has been created in which
the pre-heated shaft ends can be treated under optimum
conditions.
TurboNed
has a written quality assurance procedure for shaft end
repairs ensuring that the correct methods are adhered to
exactly for every repair. The dimensions and runout are
calibrated and inspected by TurboNed technicians, who have
been trained and certified by Castolin to carry out the
procedure. UV/penetrant tests are also incorporated in
this procedure to further ensure the integrity
of the repair.
