Incoloy 800HT (UNS N08811) Round Bar, Seamless Tube & Plate Supplier | Shanghai Hangbo Alloy Group

By Shanghai Hangbo Alloy Group Co., Ltd. | ISO 9001:2015 Certified | 2026

Quick Answer: What Is Incoloy 800HT?

Incoloy 800HT (UNS N08811 / W.Nr. 1.4959) is a nickel-iron-chromium alloy specifically designed for high-temperature structural applications. It is a controlled-composition version of Incoloy 800H, with tighter limits on carbon (0.06-0.10%) and aluminum plus titanium (0.85-1.20%). These modifications, combined with a high-temperature solution anneal, provide significantly higher creep and stress-rupture strength at temperatures above 700°C (1290°F) compared to standard 800 or 800H grades.

Product Overview

Incoloy 800HT (UNS N08811) is the "high-performance" member of the 800 series family. While sharing the base nickel-iron-chromium chemistry that resists oxidation, carburization, and sulfidation, the 800HT grade is uniquely optimized for long-term creep resistance. The addition of aluminum and titanium, coupled with a mandatory coarse grain size (ASTM No. 5 or coarser), ensures the material maintains structural integrity under sustained load in the hottest sections of industrial plants.

Key properties include:

• Superior Creep-Rupture Strength: Engineered to outperform 800H above 700°C.
• Oxidation Resistance: Forms a stable, protective chromium-rich scale.
• ASME Code Compliance: Fully approved for pressure vessel and piping design.
• Microstructural Stability: Resists embrittlement during long-term high-temperature exposure.

Incoloy 800HT is the standard material for Ethylene Cracking Furnaces, Steam Methane Reformers (SMR), and Heat-Treating Equipment. Founded in 2012, Shanghai Hangbo Alloy Group Co., Ltd. is an ISO 9001:2015 certified manufacturer delivering premium 800HT materials to over 32 countries worldwide.

Executive Standards

Chemical Composition (ASTM B408 / B409)

Shanghai Hangbo Alloy Group performs 100% OES verification to ensure every heat meets the restricted "HT" chemistry limits.

Note: The restricted (Al + Ti) range of 0.85-1.20% is the defining characteristic of 800HT vs 800H.

Mechanical & Physical Properties

Room-Temperature Mechanical Properties (Annealed)

Physical Properties

How Shanghai Hangbo Produces Incoloy 800HT

1. Incoloy 800HT Round Bars & Forgings

1. Refined Melting: Utilizing AOD (Argon Oxygen Decarburization) or VIM+ESR to achieve the precise 0.06-0.10% Carbon and 0.85-1.20% Al+Ti targets.
2. Controlled Forging: Precision hot-forging with managed deformation to ensure uniform grain structure across large sections.
3. High-Temp Solution Anneal: Mandatory heat treatment at minimum 1150°C (2100°F) to dissolve secondary phases and establish the required coarse grain size (≥ ASTM No. 5).
4. Finishing: Centerless grinding or peeling to achieve h9/h11 tolerances.

2. Incoloy 800HT Seamless Tubes & Pipes

1. Extrusion: Hot extrusion of ESR billets to form heavy-walled mother tubes.
2. Cold Processing: Precision cold pilgering or drawing to final dimensions (OD 6mm - 219mm).
3. Hydrogen Annealing: Bright annealing in a controlled atmosphere to prevent oxidation and ensure surface purity.
4. Non-Destructive Testing: 100% Eddy Current and Ultrasonic testing for nuclear or supercritical applications.

3. Incoloy 800HT Steel Plates & Sheets

1. Rolling: Hot rolling followed by solution annealing.
2. Flattening: Precision levelling to ensure flatness tolerances per ASTM B409.
3. Surface Quality: Solution annealed and pickled (White surface) or bright annealed.

Industry Applications

Quality Assurance: 7-Stage Zero-Defect Inspection

1. OES/PMI Verification: 100% chemistry check to confirm "HT" range compliance.
2. Grain Size Inspection: Per ASTM E112 to verify No. 5 or coarser (Critical for 800HT).
3. UT (Ultrasonic Testing): Per ASTM A388 to ensure zero internal defects in bars.
4. ET (Eddy Current Testing): 100% surface inspection for seamless tubes.
5. Hydrostatic Testing: Verification of pressure integrity for reformer tubes.
6. Mechanical Testing: UTS, Yield, and long-term creep testing data available.
7. Dimensional Report: Full measurement report including wall thickness concentricity.

Documentation: ISO 9001:2015, EN 10204 3.1 MTC, and SGS/BV/TÜV reports.

Frequently Asked Questions (FAQ)

Q1: What is the main difference between Incoloy 800H and 800HT?

While both are for high-temp use, 800HT has a tighter (Al + Ti) range (0.85-1.20% vs 0.30-1.20%) and a mandatory high-temp solution anneal, resulting in superior creep strength above 700°C.

Q2: What is the maximum service temperature?

Incoloy 800HT can be used up to 1100°C (2012°F) in oxidizing environments, though its primary structural strength is optimized for the 700°C to 950°C range.

Q3: Can 800HT be welded?

Yes. It has excellent weldability. We recommend using Inconel 82 (ERNiCr-3) or Inconel 617 (ERNiCrCoMo-1) filler metals for maximum high-temperature joint strength.

Q4: Is a coarse grain size mandatory?

Yes. Per ASTM standards, 800HT must have a grain size of ASTM No. 5 or coarser to qualify for the high allowable stress values in ASME codes.

Q5: What sizes of round bar are in stock?

Shanghai Hangbo stocks diameters from 10mm to 300mm. Custom forged sizes up to 500mm are available on request.

Q6: Do you provide mill test certificates?

Yes, all materials are supplied with full EN 10204 3.1 MTCs showing chemistry, mechanical properties, and grain size.

Q7: How do you handle shipping to the USA/Europe?

We offer door-to-door (DDP/DAP) logistics to 32 countries, handling all customs clearance and high-performance packaging.

Contact & CTA

Response time: within 10 minutes. Trusted by engineers in 32 countries.

Shanghai Hangbo Alloy Group Co., Ltd. — Your Trusted Partner in High-Temperature Superalloys.