White Fused Alumina WA (Abrasive Sand / Fused Alumina Powder) for Polishing Stainless Steel Sealing Parts Stainless steel sealing components, such as mechanical seal rings, valve seats and flange sealing faces, demand superior surface finish, flatness and consistent sealing performance. White fused alumina (WA, also called fused alumina or white emery) is widely adopted for precision lapping and mirror polishing. It is made of high-purity fused α‑alumina with Al₂O₃ ≥99% and Mohs hardness 9. It features steady self-sharpening property and low impurities, so it seldom leaves deep scratches and delivers uniform sealing surfaces to prevent gas or liquid leakage.
Key advantages:
- Low iron content avoids rust stains and surface contamination on stainless steel;
- Uniform sharp grains provide controlled cutting. It removes turning marks and defects efficiently without heavy deep scratches, which simplifies mirror finishing;
- Good chemical resistance. It works well with both water-based and oil-based lapping slurries;
- Tight particle size distribution per FEPA W standards. Few oversize grains reduce the risk of damaging precision sealing faces;
- Flexible for multiple processes: wet lapping, dry lapping, tumbling, polishing compound and suspended polishing liquid.
Grit selection for stainless steel seals:
- 600# 800#: Rough lapping, to remove turning lines and level the base surface
- 1000# 1200# /1500#: Intermediate lapping, the most common grade for seal faces to eliminate coarse marks
- 2000# 2500# 3000#: Fine & mirror finishing, achieving Ra 0.02–0.1 μm for high-pressure leak-free sealing
Processing note: Polish step by step from coarse to fine without skipping grades. Acid-washed high-purity grades are available for ultra-precision mechanical seals.
Typical parts: mechanical seal rings, stainless steel valve seats, flange faces, pump seals and hydraulic sealing components.