How to judge if the bearing can be used again?

"Inspect the bearings that have been removed from the equipment during regular maintenance, operation inspection and peripheral parts replacement to determine whether they can be used again or whether the condition is better than bad.The bearing and appearance of the disassembled bearing should be carefully investigated and recorded."

Secondly, check if the raceway surface, rolling surface and mating surface, as well as the wearing state of the cage are damaged or abnormal.

To determine whether the bearing can be used again, it shall be decided after considering the degree of bearing damage, machine performance, importance, operating conditions, inspection period, etc.Check the results, if the bearing has damage and abnormal conditions, the contents of the damage section to find out the cause and develop countermeasures.In addition, the inspection result shows that if there are the following defects, the bearing can not be used again, and a new bearing needs to be replaced.



a. Any of the inner and outer rings, rolling bodies, retainers with cracks and debris.

b. Any of the inner and outer rings, rolling body with peeling.

c. The raceway surface, baffle and rolling body have significant stuck injuries.

d. The cage is severely worn or the rivets are loose.

e. raceway surface, rolling body rusty and scarred.

f. There are significant indentation and indentation on the rolling surface and rolling body.

g. There is creep in the inner diameter or outer diameter of the inner ring.

h. Too hot and discolored.

i. the sealing ring and dust cover of the grease seal bearing are seriously damaged.

Check and troubleshoot in operation

The inspection items in operation include rolling sound, vibration, temperature and lubrication state of the bearing. The specific conditions are as follows:

1.Bearing rolling sound 
The size and sound quality of the rolling sound of the running bearing are checked by the acoustic meter. Even if the bearing is slightly damaged such as peeling, abnormal sound and irregular sound will be produced, and can be distinguished by the acoustic meter.

2.Bearing vibration
Bearing vibration is very sensitive to the damage of bearing, such as peeling, indentation, rust, crack and wear, etc. can be reflected in the vibration measurement of bearing. Therefore, the size of vibration can be measured by using a special bearing vibration measuring device (frequency analyzer, etc.), and the specific case of abnormality cannot be inferred through frequency division.The measured values are different due to the operating conditions of the bearing or the mounting position of the sensor, so it is necessary to analyze and compare the measured values of each machine before determining the judgment criteria.

3.Bearing temperature
The temperature of the bearing can be inferred from the temperature of the bearing outside. If the temperature of the bearing outer ring can be measured directly by oil hole, it is more suitable.Generally, the temperature of the bearing rises slowly as the operation begins and reaches a steady state after 1-2 hours.The normal temperature of the bearing varies with the machine's heat capacity, heat dissipation, speed and load.If the lubrication and installation department is appropriate, the bearing temperature will rise suddenly and there will be abnormal high temperature. At this time, the operation must be stopped and necessary precautions should be taken.The working temperature of the bearing can be monitored at any time by using a heat sensor, and the automatic alarm door or stop to prevent the occurrence of shaft accidents when the temperature exceeds the specified value.