NiCr15Fe · N06600 · Ni ≥72% · Cr 14–17% · Fe 6–10%
Nickel-chromium-iron alloy for high-temperature and caustic service. 72%+ nickel base with 15% chromium provides outstanding resistance to oxidation and scaling at temperatures well above 1000°C, and immunity to stress corrosion cracking in concentrated hot caustic — the two principal reasons to specify this alloy over stainless steel. No molybdenum — for aggressive wet chloride corrosion, specify 2.4856 (Inconel 625) instead.
| System | Designation |
|---|---|
| EN Werkstoffnummer | 2.4816 |
| EN Grade Name | NiCr15Fe |
| UNS / ASTM | N06600 / ASTM B366 WPNIC (buttweld fittings) |
| Trade Name | Inconel 600 (Special Metals/Precision Castparts) |
| AWS Filler (GTAW) | ERNiCr-3 (Inconel 82 filler) |
| Element | 2.4816 (Inconel 600) | Role |
|---|---|---|
| Ni | ≥72% | Base — primary resistance to caustic SCC, H₂O and CO₂ at temperature |
| Cr | 14.0–17.0% | Cr₂O₃ passive film — oxidation and scaling resistance |
| Fe | 6.0–10.0% | Structural strengthening at room temperature |
| C | ≤0.15% | Carbide strengthening at high temperature |
| Mo | None | Absent — no chloride pitting resistance enhancement |
Service to 1000°C+ in oxidising atmospheres. Cr₂O₃ scale is stable and non-spalling. Furnace piping, heat treatment, reformer convection sections, ethylene cracker piping.
Hot concentrated NaOH/KOH causes caustic SCC in austenitic SS. Inconel 600 is immune. Caustic evaporators, NaOH concentration process, alumina refinery Bayer process piping.
Qualified for PWR/BWR steam generator tubing and dry spent fuel storage. Radiation resistance, steam + caustic immunity. ASME III N06600 code qualification.
| Property | 2.4816 (Inconel 600) | 2.4856 (Inconel 625) |
|---|---|---|
| Mo content | None | 8–10% |
| PRE | Low (no Mo) | ~51 |
| Max service temp (oxidising) | 1000–1175°C | ~980°C |
| Caustic SCC resistance | Excellent | Good |
| Chloride pitting resistance | Poor (no Mo) | Excellent (PRE ~51) |
| Acidic reducing environments | Not suitable | Suitable |
| Choose 600 when… | High-temp oxidation, caustic, nuclear dry storage, dry gas environments | |
| Choose 625 when… | Wet chloride, mixed acids, seawater crevice, aggressive corrosion at temperature | |
