Burn damage State appears to be so-called deep-groove ball bearings: Raceway of deep groove ball bearing wheels, rolling elements and cage fever until the discoloration, dramatically softened in the rotation, cladding and damaged.
Secondly might be too much load (preload is too large). Excessive speed. Clearance is too small. Intrusion of water or other foreign objects. If the above two conditions are not so is the poor accuracy of shaft, bearings, shaft deflections. See here, I think we all want to know here, first of all, to study the lubricant and lubrication method, selected on bearing lubricant, and the amount and selection of the correct bearing. Research to meet clearance and preload, deep groove ball bearings, and improved sealing device. Check the accuracy of shaft and housing.
In deep groove ball bearing of grinding, grinding wheel and the workpiece contact areas, consume large amounts of energy, produce a lot of grinding heat, causing local transient high temperature of grinding zone. Using the theory of linear motion-heat-source heat transfer formula, calculation or the application of IR method and method of thermocouple measuring instantaneous temperature under laboratory conditions, can be found in 0.1~0.001ms in the grinding zone of instantaneous temperature can be as high as 1000~1500℃. Such instantaneous temperature, sufficient to enable the work surface a certain depth of high temperature oxide layer on the surface, non-crystalline, high-temperature tempering, quenching for the second time, crack even burn and many other changes.


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