Cosmos SDM-72 - Correlation between the Abrasion of the Bearing and Steel Dust Concentration in the Grease; Criterion

18
3-2. Correlation between the Abrasion of the Bearing and Steel Dust
Concentration in the Grease.
Table 2 shows the inspection results of correlation between the
abrasion of the bearing and steel dust concentration by disassembling
and inspecting the bearing of various rotating machinery such as
motors, pumps and blowers.
Table 2 Correlation between the Abrasion of the Bearing
and Steel Dust concentration in the Grease
Fe concentration %Wt Number of bearing and status of abrasion
0.3 – 1.0 ◆◆◆
0.1 – 0.3 ●●▲▲▲▲
0.05 – 0.1 ●●●●●
0.03 – 0.05 ○○
0.01 – 0.03 ○○○○○○○○○
0 – 0.01 ○○○○○○○○○○○
Table number of bearings 36 pieces
◆ = Large damage (continuous flaking of inner and outer rings)
▲ = Medium damage (partial flaking of inner and outer rings)
● = Slight damage (slight flaking, discolored abrasion of inner and outer rings)
○ = No abnormality
3-3. Criterion
The following table is an example of the criterion.
This criterion is relatively strict in order to carry out appropriate
corrective lubrication improvements, to detect the abnormal trend at
an early stage.
Table 3 Criterion of the Steel Dust Concentration in the Grease
Criterion Countermeasure
Normal
value
Smaller than 0.05%
Management of steel dust contents
in the grease at normal cycle
Precaution
value
0.05 – 0.1%
Repeat grease lubrication and
remeasure the steel dust
concentration 1 month later.
Irregular
value
Greater than 0.1%
Countermeasure for improvement of
lubrication, precision diagnosis at
short cycle management.