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In industrial heat treatment, petrochemical reforming, and waste incineration processes, equipment must often endure cyclic heating to 1150°C in oxidizing or mildly carburizing atmospheres. Inconel 601 (UNS N06601 / W.Nr. 2.4851) is a solid-solution strengthened nickel-chromium-iron alloy distinguished by the addition of approximately 1.4% Aluminum (Al). This aluminum addition promotes the formation of a tenacious, adherent Al₂O₃ scale, giving Alloy 601 superior resistance to oxidation, scaling, and carburization at temperatures up to 1200°C (2192°F)—performance that standard Inconel 600 or 300-series stainless steels cannot match. Shanghai COCESS Special Alloys Co., Ltd supplies Inconel 601 plate, sheet, bar, seamless tube, and welded pipe in full compliance with ASTM B168, B166, and B167, with EN 10204 3.1 certification and global export support.
Chemical Composition & Metallurgical Feature
Unlike precipitation-hardenable alloys (e.g., Inconel 718), Inconel 601 is strengthened by solid-solution atoms (Cr, Fe) and the minor alloying of Al. The key differentiator from Inconel 600 is the 21–25% Cr + 1.0–1.7% Al combination, which enables selective oxidation of aluminum to form a protective α-Al₂O₃ film.
Typical Chemistry (wt%, per ASTM B168 / AMS 5870):
Nickel (Ni): 58.0 – 63.0 % (Balance / Matrix)
Chromium (Cr): 21.0 – 25.0 % (Typically 23.0%; forms Cr₂O₃ sub-layer)
Iron (Fe): 16.0 – 20.0 % (Austenite stabilizer / Cost reducer)
Aluminum (Al): 1.0 – 1.7 % (Typically 1.2–1.4%; KEY: promotes Al₂O₃ scale for oxidation/carburization resistance)
Carbon (C): ≤ 0.10 %
Manganese (Mn): ≤ 1.0 % (Usually ≤ 0.5%)
Silicon (Si): ≤ 0.50 %
Sulfur (S): ≤ 0.015 % (Premium grade ≤ 0.005%)
Copper (Cu): ≤ 1.0 %
Physical & Mechanical Properties (Solution Annealed Condition)
Inconel 601 is typically supplied in the solution-annealed condition (1065–1175°C rapid quench). It is non-magnetic in the annealed state and offers good ductility for cold forming (bending, spinning).
Physical Constants:
Density: 8.11 g/cm³ (0.293 lb/in³)
Melting Range: 1320 – 1370 °C (2410 – 2500 °F)
Thermal Conductivity (20°C): ~11.5 W/m·K
Coefficient of Thermal Expansion (20–1000°C): ~14.2 × 10⁻⁶ /K
Continuous Oxidation Resistance Limit: Up to 1150–1200°C (2100–2190°F) in static air.
Room Temperature Mechanical Properties (Minimum per ASTM B168):
Tensile Strength (Rm): ≥ 586 MPa (85 ksi); typical 650–760 MPa
Yield Strength (Rp0.2): ≥ 241 MPa (35 ksi); typical 290–345 MPa
Elongation (A5): ≥ 30 % (typical 35–45%)
Hardness: ≤ 95 HRB (approx. ≤ 200 HB)
Key Performance Characteristics
Exceptional High-Temperature Oxidation & Scaling Resistance:
The Al₂O₃ scale formed on the surface is slow-growing and adheres well even under thermal cycling (heating/cooling), preventing flaking (spalling) that commonly occurs with chromia-only scales on 300-series SS or Alloy 600.
Good Carburization Resistance:
In endothermic (RX) or methanol-dissociated atmospheres used for case hardening, the protective oxide hinders inward diffusion of carbon, extending component life in carburizing furnaces (muffles, radiant tubes).
Sulfur-Bearing Atmosphere Caution:
In low-oxygen, high-sulfur (e.g., pure H₂S) environments, the Al/Cr scale can be reduced and lose protectiveness. However, in flue gases containing SO₂/O₂, Alloy 601 performs acceptably.
Aqueous Corrosion:
Similar to Alloy 600 but with slightly improved resistance to chloride-induced SCC due to higher Cr. Not recommended for strong reducing acids or seawater (use Alloy 625 or C-276 instead). Good resistance to caustic (NaOH/KOH) solutions.
Weldability:
Readily weldable using GTAW/GMAW with matching filler (ERNiCrFe-11 per AWS A5.14). Post-weld annealing (870–980°C) may be applied to relieve residual stresses but is not required for corrosion resistance.
Industrial Applications of Inconel 601
|
Industry / Process |
Typical Components |
Why Inconel 601? |
|---|---|---|
|
Heat Treatment & Furnace Mfg. |
Radiant tubes, muffles, retorts, hearth rolls, conveyor belts, fixturing, baskets |
Oxidation & carburization resistance to 1150°C; thermal fatigue resistance |
|
Petrochemical / Reforming |
Catalyst tube hangers, reformer furnace tube supports, pyrolysis tube shields |
High-temp strength + oxidation resistance in process heater environment |
|
Waste Incineration & Power |
Grate bars, burner nozzles, ducting, soot blower elements, flare tips |
Withstands SO₂/Cl⁻-containing flue gases and cyclic high temp |
|
Thermal Processing |
Thermocouple protection sheaths (to 1100°C), annealing covers |
Al₂O₃ scale protects against embrittlement and oxidation |
|
Aerospace / Gas Turbine (Secondary) |
Combustor liners (low-stress zones), afterburner parts |
Lightweight oxidation protection in moderate stress zones |
Supply Forms & Quality Assurance – Shanghai COCESS
Shanghai COCESS Special Alloys Co., Ltd stocks and processes Inconel 601 in:
Plate / Sheet / Strip: ASTM B168, AMS 5870 — Thk 0.5–50 mm
Round Bar / Forging Stock: ASTM B166 — Dia 6–300 mm
Seamless & Welded Tube / Pipe: ASTM B167 / B516 / B517 — OD 6–219 mm
Custom Cutting: Water-jet/plasma plate profiling, tube cut & chamfer, bar saw cut-to-length
Every order ships with EN 10204 3.1 Mill Test Report (heat analysis, mechanical results, heat treat record). Optional NDT (UT, PT, ET for tubes), third-party inspection (SGS/TÜV/DNV), and seaworthy export packaging are available.
For Inconel 601 (UNS N06601) stock availability, mill test report samples, or a project quotation, please contact Shanghai COCESS Special Alloys Co., Ltd. Our technical team can advise on forming allowances, weld filler selection (ERNiCrFe-11), and appropriate annealing practices to ensure optimal performance in your high-temperature application.
Website: https://en.cocessalloys.com
Email: sales@cocessalloys.com
