Incoloy 800H / HT (UNS N08810 / N08811): Round Bars, Seamless Tubes & Plates — Technical Data Sheet

Quick Answer: What Is Incoloy 800H / HT?

Incoloy 800H / HT (UNS N08810 / N08811) (UNS N08810 / N08811 / W.Nr. 1.4958 / 1.4959) is a premier iron-nickel-chromium superalloy formulated for service environments demanding high mechanical strength and exceptional corrosion resistance. Its high performance stems from the solid-solution strengthening combined with controlled aluminum and titanium (Al+Ti 0.85–1.20% in 800HT) for gamma-prime precipitation within its stable austenitic iron-nickel-chromium matrix. 800HT is supplied in the solution-annealed condition with chemistry controlled to ensure long-term creep-rupture strength. Operating efficiently from ambient up to approximately 1100°C (2010°F) for sustained high-temperature service, Incoloy 800H / HT is widely utilized in ethylene pyrolysis furnaces, reformer tubes, heat-treating equipment, and nuclear steam generators.

Product Overview

At the atomic level, its face-centered cubic (FCC) austenitic matrix providing excellent high-temperature stability. Its primary advantage is exceptional resistance to oxidation, carburization, and creep at temperatures well above those tolerated by stainless steels, which yields a protective chromia (Cr₂O₃) scale combined with high nickel to resist carburization and thermal cycling.

Shanghai Hangbo Alloy Group Co., Ltd., established in 2012, stands as a top-tier global manufacturer and supplier of Incoloy 800H / HT. Operating under a certified ISO 9001:2015 quality management system, we command an export network covering 50+ countries. Our portfolio contains high-precision centerless ground round bars, heavy industrial plates, and high-pressure seamless tubing engineered for critical industrial applications. By managing carbon distribution and grain refinement during melting and forging, we ensure our material provides robust structural performance under severe stress. Every order comes with 100% material traceability and certified documentation, ensuring compliance with strict global engineering standards.

Executive Standards

Shanghai Hangbo Alloy Group Co., Ltd. manufactures Incoloy 800H / HT in strict compliance with international technical specifications:

Note: Shanghai Hangbo executes 100% confirmation of chemical compliance using Optical Emission Spectroscopy (OES) for every melt lot.

Chemical Composition

The corrosion-resistant profile of Incoloy 800H / HT depends on its exact chemical balance. Chromium ensures high-temperature oxidation resistance, while molybdenum safeguards against localized pitting in chloride environments.

Mechanical Properties

Incoloy 800H / HT delivers excellent design allowable stresses. The data below outlines typical properties for annealed stock.

Room-Temperature Mechanical Properties

High-Temperature Performance: Strength Retention Analysis

Incoloy 800H / HT retains remarkable mechanical properties under thermal stress, establishing its credentials as a critical superalloy:

How Incoloy 800H / HT Is Produced

Round Bar & Forging

• 1. VIM + ESR Double Melting: ensures cleanliness and chemistry control for high-temperature service.
• 2. Hot Forging: heavy reduction refines grain structure.
• 3. Solution Annealing: controlled cooling preserves austenitic stability.
• 4. Precision Grinding: bars ground to h8/h9 tolerances.

Seamless Tube & Pipe

• 1. Billet Piercing & Extrusion: forged rounds pierced into heavy-walled hollows.
• 2. Cold Drawing / Pilgering: precise wall-thickness control for reformer and pyrolysis tubes.
• 3. Solution Annealing: full annealing for maximum high-temperature ductility.
• 4. Defect Testing: hydrostatic and Eddy Current testing per ASTM standards.

Sheet, Plate & Strip

• 1. Hot Rolling: controlled reduction avoids sigma-phase formation.
• 2. Cold Rolling: ±0.05 mm gauge control.
• 3. Leveling: tension leveling for flatness.
• 4. Pickling: nitric-hydrofluoric bath restores passive surface.

Industry Applications: Solving Engineering Challenges

Petrochemical / Ethylene

800H/HT is the standard for ethylene pyrolysis furnace tubes, transfer lines, and cracking coils operating above 900°C.

Hydrogen / Reforming

Used for reformer tubes, catalyst tubes, and outlet manifolds in hydrogen and ammonia plants.

Heat Treating

Radiant tubes, retorts, and furnace belts benefit from its carburization and thermal-fatigue resistance.

Nuclear / Power

800H is used in nuclear steam-generator tubing and intermediate heat exchangers.

Quality Assurance: 7-Stage Zero-Defect Inspection Protocol

Shanghai Hangbo Alloy Group Co., Ltd. deploys an intensive inspection matrix to support a zero-defect mandate across all production lines:

• 1. Chemical verification: OES analysis on every melt batch alongside handheld PMI validation on finished products ensures composition parameters match executive limits.
• 2. Ultrasonic Testing (UT): Performed per ASTM A388 standards across all bars and plates to confirm the absence of inner voids, seams, or gas inclusions.
• 3. Eddy Current Testing (ET): Applied 100% to tubes following ASTM E309 protocols to check surface and sub-surface continuity.
• 4. Hydrostatic Pressure Verification: Tubes undergo hydrostatic tests up to 10,000 PSI to verify wall integrity under high-pressure parameters.
• 5. Mechanical Destructive Testing: Tensile, offset yield, elongation, and Brinell hardness examinations are executed per heat lot to verify strength criteria.
• 6. Dimensional Metrology Check: Digital calipers and computerized laser sensors measure geometry, guaranteeing all diameter, wall, and length tolerances match orders.
• 7. Visual and Microstructure Audit: Surface quality checks are paired with metallographic microscope tests to evaluate grain size (ASTM E112) and phase homogeneity.

All items leave our facilities accompanied by ISO 9001:2015 certification and EN 10204 3.1 Mill Test Certificates. Third-party inspection options through SGS, TUV, or Bureau Veritas (BV) are organized upon customer request.

Frequently asked questions