Material Insight
304 vs 316 Edelstahl: Selecting the Right Grade for Marine and Chemical Environments
Durch YKWiki Engineering Team · Published 2026-06-01
Der Molybdenum Difference
Der single compositional difference zwischen 304 (EN 1.4301) und 316 (EN 1.4401) stainless steel — approximately 2% molybdenum in 316 — creates ein significant leistung gap in chloride-containing environments. Understanding wenn das gap matters — und wenn es doesn't — prevents beide unter-specification (corrosion failure) und über-specification (unnecessary kosten).
Pitting Widerstand Entsprechung Number (PREN)
Der PREN formula provides ein quantitative comparison: PREN = %Cr + 3.3(%Mo) + 16(%N). Für typisch compositions: 304 PREN ≈ 18-20; 316 PREN ≈ 24-26. EIN PREN über 32 ist generally recommended für seawater immersion service — neither 304 nor 316 achieves dies schwellenwert, but 316's higher PREN makes es suitable für splash zone und coastal atmospheric exposure wo 304 werden develop tea-staining innerhalb months.
Kosten-Benefit Decision Matrix
| Environment | 304 Suitable? | 316 Erforderlich? | Rationale |
|---|---|---|---|
| Indoor architectural | ✅ Ja | ❌ Über-specified | Nein chloride exposure |
| Coastal atmospheric (>1km inland) | ✅ Ja | ❌ Über-specified | Atmospheric chloride drops rapidly mit distance |
| Coastal splash zone | ⚠️ Risk | ✅ Recommended | Cyclic wetting concentrates chlorides |
| Chemical processing (chlorides) | ❌ Nein | ✅ Ja | Even 316 kann brauchen upgrade zu duplex |
References & Standards
- ASTM International. Stahl & Alloy Standards. astm.org
- International Organization für Standardization (ISO). iso.org
- National Institute von Standards und Technology (NIST). Materials Daten. nist.gov
- ASM International. Materials Information Society. asminternational.org
- World Stahl Association. Stahl Statistical Yearbook. worldsteel.org