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 | |
DN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.
| Size | OD (mm) |
|---|---|
| DN 15 | 21.3 |
| DN 20 | 26.9 |
| DN 25 | 33.7 |
| DN 32 | 42.4 |
| DN 40 | 48.3 |
| DN 50 | 60.3 |
| DN 65 | 76.1 |
| DN 80 | 88.9 |
| DN 100 | 114.3 |
| DN 125 | 139.7 |
| DN 150 | 168.3 |
| DN 200 | 219.1 |
| DN 250 | 273.0 |
| DN 300 | 323.9 |
| DN 350 | 355.6 |
| DN 400 | 406.4 |
| DN 450 | 457.0 |
| DN 500 | 508.0 |
| DN 600 | 610.0 |
Inconel 600 (EN 2.4816, NiCr15Fe) is used primarily in three service environments: (1) High-temperature oxidising atmospheres — the 72% Ni, 15% Cr alloy forms a stable Cr₂O₃ protective oxide at temperatures up to 1000°C+ where austenitic stainless steels are inadequate. (2) Caustic service — Inconel 600 is highly resistant to stress corrosion cracking in hot concentrated caustic (NaOH), where austenitic stainless steel and even 316L suffer caustic SCC. (3) Nuclear dry storage and reprocessing environments — the alloy's radiation resistance and caustic/steam immunity makes it the standard for nuclear HVAC and dry spent fuel storage piping.
Inconel 600 (2.4816) is Ni-Cr-Fe without molybdenum — excellent high-temperature oxidation and caustic resistance, but limited corrosion resistance in wet chloride or reducing acid environments. Inconel 625 (2.4856) adds 8–10% Mo, which dramatically increases chloride pitting resistance (PRE ~51) and reduces general corrosion in acids. If the service is primarily thermal (furnace, high-temperature gas, caustic), 600 is correct. If the service involves aggressive corrosion in wet chloride or mixed acid environments, 625 is required.
NiCr15Fe (UNS N06600): at least 72% nickel, 14–17% chromium and 6–10% iron.
