Inconel 601 is a nickel-chromium alloy (approximately 60.5 percent nickel, 23 percent chromium, 14 percent iron) with the addition of aluminum (1.0 to 1.7 percent). The aluminum content promotes the formation of a tenacious, adherent oxide layer that gives Inconel 601 outstanding resistance to high-temperature oxidation, carburization, and sulfidation. The alloy is solid-solution strengthened and is not precipitation hardenable.

The nominal chemical composition is: nickel 58.0 to 63.0 percent, chromium 21.0 to 25.0 percent, aluminum 1.0 to 1.7 percent, iron balance (typically 14 percent), silicon up to 0.5 percent, manganese up to 1.0 percent, carbon up to 0.10 percent.

Key mechanical properties (typical, annealed condition):

● Tensile strength: 550 to 690 MPa

● Yield strength (0.2% offset): 205 to 345 MPa

● Elongation: 30 to 45 percent

● Hardness: 65 to 85 HRB

● Density: 8.11 g/cm³

Inconel 601 exhibits excellent oxidation resistance up to 1,200°C (2,200°F) in cyclic and continuous service. It resists carburization and nitriding at high temperatures and has good stress rupture properties. The alloy also offers good corrosion resistance in many aqueous environments, though its primary use is for high-temperature applications.

Standards: ASTM B168 (plate, sheet, strip), B166 (rod, bar, wire), B167 (pipe, tube). AMS 5870 (sheet), AMS 5715 (bar). ASME SB-168, SB-166, SB-167.

Typical applications of Inconel 601 include:

● Industrial heating: radiant tubes, retorts, muffles, and furnace rolls in heat treatment and annealing furnaces.

● Petrochemical processing: heater tubes, reformers, and ethylene cracking furnaces.

● Power generation: superheater and reheater tubing in boilers.

● Gas turbine components: combustion chambers, transition ducts, and afterburner parts.

● Automotive exhaust systems: diesel glow plugs and exhaust gas recirculation (EGR) components.

● Thermal processing equipment for metals and ceramics.

Comparison with Inconel 600: Inconel 601 has higher oxidation resistance at temperatures above 1,100°C due to its aluminum content. Inconel 600 is preferred for chloride stress corrosion cracking resistance in aqueous environments. Inconel 601 is generally the better choice for sustained high-temperature service in air or combustion atmospheres.

Selection guidance: Choose Inconel 601 for high-temperature applications requiring exceptional oxidation resistance up to 1,200°C, especially in cyclic heating conditions. For lower temperatures or where aqueous corrosion is the primary concern, Inconel 600 or 625 may be more suitable. For maximum high-temperature strength rather than oxidation resistance, consider Inconel 617 or 230.