Microspalling of bearing steel

Microspalling of bearing steel 

   Microspalling or surface damage is a surface failure mechanism commonly found in modern mechanical parts with heavy duty, non-conformal, roll-slip lubrication contacts (such as bearings and gears). This damage is caused by rolling contact fatigue of rough peak level, which is caused by repeated rough peak stress fluctuations during rolling contact and can be represented by numerous micro-cracks and micro-spalling formed on the rolling surface. It generally occurs under poor lubrication conditions (low Λ value) when the thickness of the oil film is insufficient to completely separate the rolling surface. The load is carried by rough peak-rough peak contact and lubricant respectively. Because the current trend is to use thinner lubricants to maximize the efficiency of mechanical parts, the focus is on understanding micro-spalling and designing rolling surfaces that are more resistant to micro-spalling and withstand higher power densities.