Floating Oil Seal Ring Material: 420 / 440C Stainless Steel. The sealing surface requires a mirror finish of Ra 0.04‑0.08 μm with no deep scratches. The mainstream abrasive used in the industry is white fused alumina micropowder (national standard lapping micropowder, JIS lapping micropowder), Al₂O₃ ≥99.2%, acid-washed, dried and magnetic separated. Oversized particles are strictly controlled to prevent fatal scratches on the sealing surface.
Common Grades of White Fused Alumina Micropowder for Floating Oil Seal Lapping
| Process | JIS Mesh Size | D50 Particle Size | Description |
|---|---|---|---|
| Rough Lapping (removal of tool marks, flatness correction) | 1200# / 1500# | 7‑10 μm | Remove machining tool marks and correct flatness as preparation for fine lapping |
| Fine Lapping (mainstream for mass production) | 2500# | 5‑7 μm | Final lapping powder adopted by most floating oil seal manufacturers, directly achieving Ra 0.06‑0.08 μm to meet factory sealing specifications |
| High-End Ultra-Fine Mirror Finishing | 3000‑4000# | 2.5‑5 μm | For premium oil seals targeting lower roughness; lower efficiency and higher cost |
