Overview
Seamless N10665 Nickel Alloy Tube (UNS N10665, EN 2.4617) is a nickel-molybdenum alloy optimized for unparalleled resistance to reducing acids, particularly hydrochloric acid (HCl). Composed of 65% nickel, 28-30% molybdenum, ≤1% iron, and trace cobalt, it eliminates the iron-rich intermetallic phases of earlier B-series alloys (e.g., B-1), providing superior resistance to grain boundary corrosion. Manufactured via hot-extrusion and cold-drawing to meet ASTM B622 and ASME SB622, the seamless construction ensures uniform wall thickness and freedom from weld defects critical for aggressive chemical service.
Nickel Alloy N10665’s single-phase austenitic microstructure remains stable during welding, minimizing the risk of sensitization in high-temperature reducing environments.
Chemical Composition
| Grade | Ni | Cr | Mo | Fe | C
| Si | Co | Mn | P | S |
| N10665 | Bal | ≤1.00 | 26.00-30.00 | ≤2.00
| ≤0.02 | ≤0.10 | ≤1.00 | ≤1.00 | ≤0.04 | ≤0.03 |
Features
Superior Reducing Acid Resistance: Resists concentrated HCl (up to 37% at 120°C) and sulfuric acid (up to 50% at 150°C), outperforming all stainless steels and most nickel alloys in pure reducing conditions.
Immunity to Intergranular Corrosion: Low iron (<1%) and controlled carbon (<0.02%) prevent the formation of brittle Mo2C carbides, ensuring corrosion resistance even in as-welded conditions.
High Thermal Conductivity: Offers thermal conductivity twice that of 316L stainless steel, making it suitable for heat exchanger applications requiring efficient heat transfer.
Moderate Formability: Can be cold-formed for simple geometries (≤30% reduction) but requires preheating (150-200°C) for hot forming; GTAW with N10665 filler metal is recommended for welding.
Mechanical Properties
(as per ASTM B622)
Grade | Tensile Strength ksi(MPa) | Yield Strength ksi(MPa) | Elongation(%) |
N10665 | ≥110(760) | ≥51(350) | ≥40 |
Application
Hydrochloric Acid Processing: Used in pickling tanks, vaporizers, and pipelines for steel pickling, titanium dioxide production, and pharmaceutical HCl synthesis.
Petroleum Refining: Ideal for alkylation units, sulfuric acid regenerators, and equipment handling high-sulfur crude oil byproducts.
Chemical Synthesis: Employed in reactors and condensers for manufacturing organic intermediates (e.g., methanol, formaldehyde) in reducing atmospheres.
Metallurgy: Used in pressure leach vessels for nickel/cobalt ore processing, resisting chloride-induced corrosion in H2SO4-based leaching solutions.
Material Summary
Nickel Alloy N10665 is a solid solution strengthened, nickel-molybdenum alloy, with significant resistance to reducing environments like hydrogen chloride gas, and sulfuric, acetic and phosphoric acids. Molybdenum is the primary alloying element which provides significant corrosion resistance to reducing environments.
Nickel Alloy N10665 seamless pipe & tube is a kind of pipe or tube without weld seam. So its leakproofness and high pressure resistance is more better than that of welded pipe & tube. Nickel Alloy N10665 has excellent corrosion resistance and high temperature resistance. So if your project demand to work in the special or extreme environment, our Nickel Alloy N10665 seamless pipe & tube is your best choice.
Thanks to its superior composition and performance, Nickel Alloy N10665 is frequently chosen for applications requiring a high level of durability and chemical resistance. When manufactured as a seamless stainless steel tube, it offers enhanced integrity under pressure and in corrosive environments, making it a reliable solution for demanding industrial conditions.
