Introduction

Incoloy 800HT (UNS N08811 / Alloy 800HT / W.Nr. 1.4959) is a high‑carbon version of Incoloy 800H, offering superior creep rupture strength at temperatures above 700°C. Incoloy 800HT seamless pipe, reformer tube, cracking tube, pigtail, transfer line, round bar, forging, plate, sheet, and welding wire are widely used in steam reformers, hydrogen plants, ethylene cracking furnaces, ammonia reformers, and methanol production units. This nickel‑iron‑chromium alloy provides excellent oxidation and carburization resistance up to 1100°C. Compared to Incoloy 800H, Alloy 800HT delivers enhanced thermal stability and creep resistance for long‑term petrochemical service. Available per ASTM B407, B408, B409, B163, or customer specifications.

Chemical components（%）

Mechanical properties

Physical properties

Incoloy 800HT  Available Products and Standard

1. GB/T 15007 (Nickel and Nickel Alloy Plate, Strip, and Foil)

Domestic Grade: NS113 (GB/T 15007) / Incoloy 800HT equivalent

Type: Wire / Strip / Bar / Sheet / Seamless Tube / Pipe / Forgings

Size Range:

• Incoloy 800HT Wire: 0.1 – 15.0 mm dia

• Incoloy 800HT Strip: 0.05 – 5.0 mm thick × 5 – 500 mm wide

• Incoloy 800HT Round Bar: 8 – 355 mm dia

• Incoloy 800HT Sheet / Plate: 0.5 – 180 mm thick

• Incoloy 800HT Seamless Tube / Pipe: Custom sizes available

Surface: Annealed, Bright, Pickled, Ground

Testing: Chemical analysis, mechanical test (tensile strength, yield strength, elongation), hardness test, intergranular corrosion test, high-temperature creep rupture test, dimensional inspection

2. ASTM B407 (Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube)

Grade: UNS N08811 / Incoloy 800HT / Alloy 800HT / W.Nr. 1.4959

Type: Seamless Pipe / Seamless Tube / Reformer Tube / Cracking Tube / Heat Exchanger Tube

Size Range:

• Incoloy 800HT Seamless Pipe: 6 – 610 mm OD × 1 – 50 mm wall thickness

• Incoloy 800HT Seamless Tube: Custom sizes for reformer and cracking service

Surface: Annealed, Pickled, Bright

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hydrostatic test, eddy current test, creep rupture test, dimensional inspection

3. Additional Standards (upon request)

• ASTM B408 – Rod and Bar (Round Bar, Wire)

• ASTM B409 – Plate, Sheet, and Strip

• ASTM B163 – Seamless Condenser and Heat Exchanger Tube

• ASTM B564 – Forgings / Forged Ring / Flange

• ASTM B366 – Fittings (elbows, tees, reducers)

• ASME SB407 / SB408 / SB409 – Boiler and Pressure Vessel Code

• AMS 5871 – Bar, Wire, Forgings

Testing for additional products: Chemical analysis, mechanical test, hardness test, PMI (positive material identification), ultrasonic test, dimensional inspection

Advantages

(1)Superior creep rupture strength above 700°C: As a high‑carbon variant of Incoloy 800H, Incoloy 800HT reformer tube and seamless pipe deliver higher creep resistance for long‑term service in steam reformers and ethylene cracking furnaces.

(2)Excellent oxidation and carburization resistance up to 1100°C: Alloy 800HT plate and sheet withstand aggressive carbon‑rich atmospheres, making them ideal for transfer lines and pigtails in petrochemical plants.

(3)Enhanced thermal stability: Incoloy 800HT round bar and forging retain their austenitic structure and mechanical properties after prolonged exposure to high temperatures, outperforming standard 800H.

(4)Good weldability and fabricability: Incoloy 800HT welding wire and strip enable reliable fabrication of complex furnace components such as radiant tubes and heat exchanger coils.

(5)Proven for hydrogen and ammonia production: UNS N08811 seamless tube is the preferred material for reformer tubes in hydrogen plants, ammonia reformers, and methanol production units.

Applications

(1)Steam reformer tubes (hydrogen plants) – Incoloy 800HT seamless pipe and reformer tube are standard for primary and secondary reformers, handling high‑pressure steam and hydrocarbon mixtures at 850–1000°C.

(2) Ethylene cracking furnaces – Alloy 800HT cracking tube and pigtail resist carburization and thermal fatigue in ethylene production, extending tube life between decoking cycles.

(3)Transfer lines and pigtails – Incoloy 800HT seamless tube and fitting connect furnace outlets to quench systems, where high creep strength and oxidation resistance are critical.

(4) Radiant tubes and heat treating fixtures – Incoloy 800HT plate and strip are used in annealing furnaces, carburizing fixtures, and radiant burner tubes requiring thermal stability up to 1100°C.

(5) Ammonia and methanol reformers – Incoloy 800HT forging and flange serve in high‑temperature process piping and catalyst tube supports for synthetic gas production.

(6) Nuclear steam generators (advanced designs) – Incoloy 800HT heat exchanger tube is specified for very high‑temperature gas‑cooled reactors (VHTR) where creep strength is paramount.

MONO Group is one of Superalloy, Nickel alloy, high Temperature alloy manufacturer&Supplier&Wholesaler from China,We can supply high quality alloy plate,sheet,round bar,tube.pipes,fittings,flange,and custom parts in accordance with ASTM, ASME, DIN, ISO, GB, and other international standards. For inquiries or to request a quote , please freely contact us at info@monokj.com.