False Brinelling
False brinelling is a fretting wear failure mode in rolling-element bearings caused by small-amplitude oscillations or vibrations that produce micromovements between rolling elements and raceways. This leads to material removal and polished, crater-like indentations without plastic deformation, distinguishing it from true brinelling.
In shop floor maintenance, false brinelling primarily occurs when bearings are stationary but subjected to external vibration, such as during transport by rail or sea, storage near forklifts, or equipment lockdown. The lubricant film cannot replenish due to micro-oscillations, creating boundary lubrication and metal-to-metal contact. In CMMS/Asset Reliability systems like ServiceGrid, it is flagged as a motion problem requiring vibration isolation, proper preloading, or transport-specific lubrication protocols to prevent damage.
- Transporting unsecured bearings without strapping the shaft or housing, exposing them to train or forklift vibration.
- Using inadequate or depleted lubricant that fails to form an elastohydrodynamic film under micromotion.
- Neglecting preloading or vibration isolation during storage or shipping, allowing free oscillation.
How to distinguish false from true brinelling microscopically?
False brinelling shows polished, shiny surfaces with no raised shoulders and machining marks removed; true brinelling retains original machining marks and has raised shoulders from plastic deformation.
What wear particles characterize false brinelling?
Magnetite (Fe₃O₄) particles, appearing as black debris surrounding wear scars, confirm fretting wear.
Why does false brinelling disappear after break-in?
The polished wear pattern is not permanent deformation; initial rotation replenishes lubricant and smooths the surface, masking the defect.
Is false brinelling ISO-classified?
Yes, under ISO 15243 Section 5.3.3.3 as fretting corrosion, distinct from plastic deformation.
Can false brinelling occur in rotating bearings?
Rarely; it is overwhelmingly a non-rotating, stationary phenomenon, though extreme low-amplitude dithering in lightly loaded rotating systems may trigger it.
What lubricant property mitigates false brinelling?
Lubricants with high film strength and anti-wear additives (e.g., zinc dialkyldithiophosphate) that sustain boundary lubrication during micromotion.
Does false brinelling cause fatigue?
Yes, the craters act as stress concentrators, accelerating rolling contact fatigue and eventual spalling.
What is the root cause in tribological terms?
Mixed/boundary lubrication failure due to inability of lubricant to replenish the contact zone under oscillatory motion, leading to adhesive wear and material loss.
Can preloading prevent it?
Yes, preloading reduces free oscillation amplitude, minimizing micromovement.
What CMMS alert should trigger in ServiceGrid?
Alert on bearing vibration during shutdown/storage with condition: non-rotating plus external vibration source detected.