Overview
250 mesh is the precision SKU in our 316L line. Cut point ≈58 µm, D50 ≈ 40–48 µm; a single layer typically yields filtration efficiency in the 1–5 µm range after sintering. This is the working size for PTFE membrane substrates and for the fine layer of precision sintered cartridges.
For membrane converters, the substrate's surface roughness drives PTFE bond strength and back-pulse life. Our 250-mesh fine fraction is sieved to a tighter PSD (D90 capped at ≈70 µm) so a few oversize particles do not dominate substrate roughness.
Chemistry
UNS S31603, identical to other 316L SKUs. Per-batch OES verification.
Physical properties
| Property | Method | Typical value |
|---|---|---|
| Sieve cut point | Mechanical sieving | 250 mesh (≈58 µm) passing |
| D10 / D50 / D90 | Laser diffraction | 18 / 45 / 65 µm |
| Apparent density | ASTM B212 | 2.5–2.8 g/cm³ |
| Tap density | ASTM B527 | 3.3–3.7 g/cm³ |
| Oxygen content | LECO | ≤ 3000 ppm (≤ 2000 ppm available as a custom option) |
Application notes
- PTFE membrane substrate — pressed and sintered followed by secondary surface finishing yields Ra ≤ 5 µm, a workable surface for membrane lamination and pulse-jet cleaning durability.
- Food-grade and pharmaceutical sintered cartridges — 316L chemistry plus precision PSD control supports FDA contact-material qualification at the device level.
- Polymer melt filtration — high-temperature, high-pressure filtration where pore-size predictability is the deciding spec; 250-mesh fine layer is the workhorse.
Available upgrades
- Tighter PSD (250 / -325 mesh blend)
- Lower oxygen target (≤ 2000 ppm)
- Dual-element blends (e.g. with 304L or -325 mesh fines, blended by weight ratio)
All available as custom orders; 3–4 weeks from spec confirmation to delivery.