Material Family

Nickel-Iron-Chromium Austenitic Alloy (High-Temperature Optimized) Coil/Strip

The coiled form of the premium high-temperature, creep-resistant grades.

Mandatory Supply Condition

Solution Annealed with Controlled Coarse Grain Structure (ASTM grain size 5 or coarser). This is not optional—it is essential to develop the specified high-temperature creep strength.

This is the primary reason to specify 800H/HT over standard 800 coil for high-temperature designs.

Chemical Composition (Typical wt.%)

Common: Ni 30.0-35.0, Cr 19.0-23.0, Fe ≥39.5
C: 0.05 - 0.10
Al: 0.15 - 0.60
Ti: 0.15 - 0.60
800HT Specific: (Al + Ti) must be 0.85 - 1.20

Controlled Carbon (C) is key for strength. 800HT's required (Al+Ti) sum ensures optimal precipitation strengthening for the best creep performance.

Mechanical Properties (Annealed Coil, Room Temp)

Tensile Strength (Rm): 450 - 600 MPa (min yield varies by spec)
Yield Strength (Rp0.2): 170 - 240 MPa (min)
Elongation (A): 30% min

Room temperature properties are similar to standard 800. The critical properties are elevated temperature strength and creep data.

Coil Physical Specifications (Typical)

Thickness: 0.10mm - 3.0mm (0.004" - 0.125")
Width: 10mm - 600mm (0.4" - 24")
Coil I.D.: 300mm, 405mm, 508mm (12", 16", 20")
Coil Weight: 50kg - 2000kg

Supplied with precision gauge and width tolerances suitable for high-speed forming and stamping.

Key Performance Attributes

• Excellent and Predictable Creep & Stress-Rupture Properties above 540°C.
• Excellent resistance to oxidation, carburization, and sulfidation.• Good resistance to chloride stress corrosion cracking.• Good weldability and fabricability in the annealed condition.

The benchmark coil material for high-temperature, pressurized, or load-bearing components in coil form.

Primary Service Range

600°C - 950°C (1110°F - 1740°F) for maximum benefit of enhanced creep strength.

Optimized for long-term exposure in this high-temperature window, unlike standard 800 coil.

Key Standards (Strip/Coil)

ASTM B409 / ASME SB-409 (Sheet, Strip, and Plate)
MANDATORY: ASTM B407 (Specifies the grain size and heat treatment requirements for UNS N08810 & N08811)

Purchasing to ASTM B409 alone is insufficient. Orders must specify compliance with ASTM B407 to guarantee the high-temperature properties.

Typical Coil Applications

• Petrochemical: Reformer furnace internals (shims, spacers, clips), pigtails, tube supports.
• Heat Exchangers: High-temperature fin stock, air preheater elements for aggressive flue gases.
• Industrial Furnaces: High-temperature conveyor belts, mesh belts, radiant tube hangers.
• Power Generation: Spacer and seal strips in superheaters/reheaters.

Used to manufacture critical, repetitive high-temperature components that must resist creep deformation under load.