Incoloy Alloy 890 Forgings Forged bars, seamless rolled rings, flanges, discs and sleeves in UNS N08890, made in Jiangyin, China

What alloy 890 is, and why it is forged

Alloy 890 is the newest member of the Incoloy family of heat resistant alloys. It pairs the high chromium level of alloy 803 with deliberate additions of silicon, molybdenum and niobium: silicon and chromium build the protective surface oxide that blocks carbon and sulphur ingress, while molybdenum and niobium raise creep and stress-rupture strength above 980 °C (1800 °F). The alloy is covered by US Patent 5,873,950, granted 23 February 1999.

The grade is single phase and cannot be strengthened by ageing, so the benefit of forging it comes from the working process. Forging breaks down the cast structure, closes porosity and refines the grain, and a controlled finishing temperature keeps grain size uniform through the section. A forged and solution-annealed N08890 ring or hub gives more consistent properties through the thickness than the same shape cut from plate or machined from a cast blank, and it carries no weld seam that can crack under creep loading.

We supply alloy 890 to drawing. The melt route is agreed with the customer, normally ESR, or VIM + ESR + VAR where cleanliness is critical. Material is forged on hammers and a 4500 t hydraulic press, ring rolled where the geometry suits it, solution annealed, then rough or finish machined.

Chemical composition of Incoloy alloy 890 (UNS N08890)

Nominal analysis in weight percent, as published by the alloy originator. Heat analysis for every forging we ship is reported on the mill certificate.

Physical and thermal properties

Elastic modulus at temperature

Mean coefficient of thermal expansion

Mechanical properties, room and elevated temperature

Creep and rupture behaviour

Creep and stress-rupture strength are close to alloy 803 and slightly above alloy 800H and 800HT. The margin grows above 980 °C (1800 °F), where the molybdenum and niobium additions have most effect. For pressure-retaining or life-limited parts, agree the stress-rupture test plan at the enquiry stage, before the forging is made.

Heat treatment and our forging route

Alloy 890 is annealed by heating to 1121–1204 °C (2050–2200 °F), soaking for a time matched to the section thickness, then cooling rapidly in air or water quenching. Slow cooling through the intermediate range is what to avoid: extended exposure there precipitates carbides and sensitizes the alloy. Sensitization rarely matters in the dry, hot service this grade is bought for. It does matter if the part will also see an aqueous acid environment, which is a reason to ask for documented quench records.

Welding and fabrication

Forming procedures for alloy 890 are the same as those used for alloy 800HT and alloy 803. Work hardening during cold deformation is comparable to other Incoloy grades. The alloy can be joined by GMAW, GTAW and SMAW. Consumable choice follows the governing service requirement.

Alloy 890 forged forms and sizes we produce

Alloy 890 vs alloy 803 vs alloy 800H/800HT

These three grades compete for the same furnace and pyrolysis duties, and the choice usually comes down to how aggressive the carbon or sulphur activity is at the top of the temperature range.

Related grades we forge: Incoloy 800, Incoloy 800H, Incoloy 800HT, Incoloy 825, Inconel 601, Inconel 617, Inconel 625, Haynes 230.

Where alloy 890 forgings are used

• Ethylene and petrochemical pyrolysis: coil supports, return bends, header components and fittings exposed to coking and carburizing atmospheres.
• Heat-treatment plant: retorts, muffles, radiant tube supports, fixtures, baskets and trays cycling to 1150 °C and above.
• Carburizing and nitriding furnaces: fans, shafts, seals and hearth hardware where carbon pickup destroys stainless steel.
• Calcining and rotary kiln hardware: flights, seals and support rings in sulphur-bearing atmospheres.
• Waste incineration and energy from waste: grate and duct components handling mixed oxidizing and sulphidizing gas.
• Power generation: high-temperature ducting, hangers and structural forgings.

Quality, testing and documents

• Chemistry: heat analysis plus PMI on the finished forging; product analysis on request.
• Mechanical testing: room-temperature and elevated-temperature tensile, hardness; stress rupture by agreement.
• Non-destructive testing: ultrasonic to ASTM A388 or customer acceptance class, plus liquid penetrant to ASTM E165.
• Metallography: grain size to ASTM E112, microstructure photographs on request.
• Corrosion and sensitization: ASTM A262 Practice C where the part may see aqueous service.
• Documents: EN 10204 3.1 certificate as standard, 3.2 with a third-party inspector (TÜV, SGS, BV, Lloyd's) when specified; full traceability from heat number to piece mark.
• Dimensional: inspection report against your drawing, with forging tolerances agreed before production.

Sources and revision history

• Chemistry, physical constants, modulus, expansion, tensile, heat treatment and consumable data: Special Metals Corporation, INCOLOY alloy 890 technical bulletin, publication SMC-089 (2004).
• Product form specifications: ASTM B407, ASTM B408, ASTM B409, ASTM B906.
• Patent reference: US 5,873,950, 23 February 1999.
• Forging capability, process route, testing scope and commercial terms: Jiangyin Jiangnan Metal Co., Ltd.
• Revision history: published 11 June 2019. Checked against SMC-089 and updated on 17 August 2026; the room-temperature tensile values were corrected, having previously been taken from the 1100 °C row.