1. Surface scoring on single-row deep groove ball bearings: Cutting abrasive particles identified in ferrographic analysis, with non-ferrous metal composition.

2. Surface corrosion on bearing journal of single-row deep groove ball bearings: Spectral analysis reveals abnormal iron concentration; ferrographic analysis shows numerous submicron particles of iron composition; lubricating oil exhibits excessive moisture content or acid value.

3. Bearing shell surface corrosion: Spectral analysis revealed abnormal concentrations of non-ferrous metal elements; ferrography showed numerous submicron wear particles composed of non-ferrous metals; lubricating oil contained excessive moisture and acid value.

4. Bearing shell back micro-motion wear: Spectral analysis detected abnormal iron concentrations; ferrography contained numerous submicron wear particles composed of iron; lubricating oil exhibited abnormal moisture and acid value. Under liquid lubrication conditions, sliding surfaces are separated by lubricating oil, preventing direct contact. This significantly reduces friction losses and surface wear, while the oil film also possesses certain vibration-damping capabilities.

5. Scratching on shaft neck surfaces of single-row deep groove ball bearings: Ferrographic analysis reveals iron-based cutting abrasive particles or black oxide particles, with temper colours present on the metal surface.