SKF - Rolling Bearings

Inspection and cleaning
Bearing storage
The conditions under which bearings, seals
and lubricants are stored can have an adverse
effect on their performance. Inventory control
can also play an important role in performance,
particularly if seals and lubricants are
involved. Therefore, SKF recommends a “first
in, first out” inventory policy.
Storage conditions
To maximize the service life of bearings, SKF
recommends the following basic housekeeping
practices:
• Store bearings flat, in a vibration-free, dry
area with a cool, steady temperature.
• Control and limit the relative humidity of the
storage area as follows:
––
75% at 20 °C (68 °F)
––
60% at 22 °C (72 °F)
––
50% at 25 °C (77 °F)
• Keep bearings in their original unopened
packages until immediately prior to mounting
to prevent the ingress of contaminants
and corrosion.
• Bearings that are not stored in their original
packaging should be well protected against
corrosion and contaminants.
Inspection and cleaning
As with all other important machine components,
rolling bearings must be cleaned and
inspected frequently. The intervals between
these inspections depend entirely on the operating
conditions.
If it is possible to ascertain the condition of a
bearing during service, by using condition
monitoring equipment, listening to the bearing
with a stethoscope, monitoring temperature
or lubricant analysis, then it is usually sufficient
to clean and inspect all components
annually. Where loads are heavy, the frequency
of inspection should be increased.
After the bearing components have been
cleaned with a suitable solvent such as white
mineral spirits, they should be oiled or
greased immediately to prevent corrosion.
This is particularly important for bearings in
machines that are left to stand for extended
periods.
Shelf life of open bearings
SKF bearings are coated with a rust-inhibiting
compound and suitably packaged before distribution.
For open bearings, the preservative
provides protection against corrosion for
approximately five years, provided the storage
conditions are appropriate.
Shelf life of capped bearings
The maximum storage interval for capped SKF
bearings is dictated by the lubricant inside the
bearings. Lubricant deteriorates over time as
a result of ageing, condensation, and separation
of the oil and thickener. Therefore, capped
bearings should not be stored for more than
three years.
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