Name: Incoloy 800HT
Brand: Incoloy

Material Overview

Incoloy 800HT material profile

A concise grade introduction for buyers who need to confirm composition, properties, standards, available forms and suitable applications before sending an inquiry.

Engineering profile

Incoloy 800HT, designated UNS N08811, is a controlled-composition nickel-iron-chromium alloy developed for long-term service at elevated temperatures. Its specified carbon content, higher combined aluminum and titanium level, coarse grain structure and high-temperature solution treatment provide improved creep and stress-rupture strength compared with conventional Alloy 800 and many Alloy 800H products. Incoloy 800HT also offers useful resistance to oxidation, carburization and nitriding atmospheres, making it suitable for reformer tubing, ethylene furnace components, radiant tubes, pigtails, manifolds, retorts, steam superheater tubing and other high-temperature process equipment.

Technical data on this page is for material selection reference. Final acceptance values should be confirmed by the purchase standard, heat treatment condition, product form, size and material test certificate.

Chemical Composition

Incoloy 800HT composition range

The following table shows common limiting composition values for Alloy 625 / UNS N06625. Actual product chemistry is reported by heat on the material test certificate.

Element	Symbol	Composition, wt.%	Role in Incoloy 800HT
Nickel	Ni	30.0-35.0	Maintains the austenitic structure and supports resistance to carburization and thermal degradation.
Chromium	Cr	19.0-23.0	Provides resistance to oxidation and other high-temperature corrosive atmospheres.
Iron	Fe	39.5 min	Forms the principal balance of the alloy and improves resistance to internal oxidation.
Carbon	C	0.06-0.10	Controlled within a narrow range to improve creep and stress-rupture strength.
Aluminum	Al	0.25-0.60	Contributes to high-temperature strength and oxidation resistance.
Titanium	Ti	0.25-0.60	Supports high-temperature strength and metallurgical stability.
Aluminum + Titanium	Al + Ti	0.85-1.20	This restricted combined content distinguishes UNS N08811 from ordinary Alloy 800H chemistry.
Manganese	Mn	1.50 max	Controlled minor alloying and deoxidizing element.
Silicon	Si	1.00 max	Controlled for processing, weldability and high-temperature performance.
Copper	Cu	0.75 max	Controlled residual element.
Sulfur	S	0.015 max	Restricted to support hot workability and weld quality.

Physical Properties

Key physical and thermal data

These values help customers compare density, thermal behavior, magnetic response and conductivity during early material selection.

Property	Metric Value	Imperial Value	Condition / Notes
Density	7.94 g/cm3	0.287 lb/in3	Room temperature
Melting Range	1357-1385 °C	2475-2525 °F	Typical range
Specific Heat	460 J/kg·°C	0.11 Btu/lb·°F	Mean value from 0 to 100 °C
Thermal Conductivity	11.5 W/m·°C	Approx. 80 Btu·in/ft²·h·°F	Approx. 20 °C
Electrical Resistivity	0.989 µΩ·m	Approx. 595 ohm-cmil/ft	Approx. 20 °C
Modulus of Elasticity	196.5 GPa	28.5 x 10³ ksi	Approx. 20 °C, dynamic method
Shear Modulus	73.4 GPa	10.64 x 10³ ksi	Approx. 20 °C
Mean Coefficient of Thermal Expansion	14.4 µm/m·°C	Approx. 8.0 x 10^-6 in/in·°F	Mean value from approximately 20 to 100 °C
Magnetic Permeability	Approx. 1.014	Essentially non-magnetic	Annealed material at room temperature

Mechanical Properties

Room-temperature mechanical properties

Mechanical properties vary with product form, size, processing route and heat treatment. The table below summarizes commonly referenced nominal values for material selection.

Product Form / Condition	Tensile Strength	Yield Strength, 0.2%	Elongation	Technical Note
Rod and bar – solution annealed	450 MPa (65 ksi) min	170 MPa (25 ksi) min	30% min	Representative ASTM B408 room-temperature minimum requirements; dimensional provisions may affect the applicable values.
Plate, sheet and strip – solution annealed	450 MPa (65 ksi) min	170 MPa (25 ksi) min	30% min	Representative ASTM B409 requirements for controlled-grain UNS N08811 material.
Seamless pipe and tube – solution annealed	450 MPa (65 ksi) min	170 MPa (25 ksi) min	30% min	Representative ASTM B407 requirements; confirm the product size and test specimen provisions.
Welded heat-exchanger tube – solution annealed	450 MPa (65 ksi) min	170 MPa (25 ksi) min	30% min	Representative ASTM B515 requirements with controlled grain size and specified tube testing.
Representative annealed plate at 540 °C	Approx. 432 MPa (62.7 ksi)	Approx. 90 MPa (13.0 ksi)	Approx. 13%	Typical short-time elevated-temperature data, not a design allowable stress.
Representative annealed plate at 760 °C	Approx. 236 MPa (34.2 ksi)	Approx. 74 MPa (10.7 ksi)	Approx. 13%	Typical short-time data; long-duration design must use approved creep and rupture values.

Mechanical values are representative or specification-based and must not be used as universal design allowables. Final acceptance depends on the product standard, dimensions, solution treatment, grain size, test orientation and material test certificate. High-temperature equipment must be designed using the applicable ASME or project-approved creep and stress-rupture data.

For pressure equipment, aerospace parts or project-specific acceptance, use the minimum requirements in the specified ASTM, ASME, AMS, EN or customer drawing rather than nominal values.

Standards & Specifications

Common Incoloy 800HT standards by product form

YSN128 can quote Alloy 625 products according to ASTM, ASME, AMS, EN, DIN, ISO or customer drawing requirements. Certificate scope can be matched to the purchase order.

Product Form	Common Standards	Typical Supply Item	Certificate / Inspection
Plate, Sheet and Strip	ASTM B409 / ASME SB409, ASTM A240 / ASME SA240, EN 10028-7, EN 10095	Controlled-grain plate, sheet, strip and cut blanks	EN 10204 3.1 MTC, chemistry, tensile test, grain size and heat-treatment record
Rod and Bar	ASTM B408 / ASME SB408, ISO 9723, EN 10095	Round bar, rod, flat bar and machined blanks	MTC, PMI, tensile test, grain size and dimensional inspection
Seamless Pipe & Tube	ASTM B407 / ASME SB407, ASTM B163 / ASME SB163, ASTM B829 / ASME SB829	Seamless process pipe, furnace tube and heat-exchanger tube	Hydrostatic or eddy-current testing, grain size, MTC and dimensional inspection
Welded Pipe	ASTM B514 / ASME SB514 with ASTM B775 / ASME SB775	Longitudinally welded process and high-temperature pipe	Weld examination, pressure or specified NDT, heat-treatment record and MTC
Welded Heat-Exchanger Tube	ASTM B515 / ASME SB515 with ASTM B751 / ASME SB751	Boiler, condenser and heat-exchanger tubing	Flattening, flange and specified nondestructive tests, grain size and MTC
Forgings, Flanges and Valve Parts	ASTM B564 / ASME SB564, ISO 9725	Rings, discs, flanges, blocks and pressure-containing forgings	Tensile test, grain size, heat-treatment record, PMI, UT when specified and MTC
Wrought Fittings	ASTM B366 / ASME SB366	Elbows, tees, reducers, caps and custom wrought fittings	PMI, dimensional inspection, heat-treatment record and MTC
Pressure Equipment Design	Applicable ASME BPVC sections and current Code Cases	Boiler, pressure-vessel and high-temperature piping components	Design review must use the current Code edition, material listing and allowable stresses
Welding Products	AWS A5.14 ERNiCr-3; higher-temperature filler selected by qualified WPS	GTAW, GMAW and submerged-arc welding consumables	Consumable certificate, lot traceability and procedure qualification

Available Product Forms

Incoloy 800HT supply range

Review available product forms, size ranges, standards and delivery options for this alloy.

Form	Common Size Range	Delivery Condition	Typical Applications	Page Link
Pipe & Tube	OD 6-610 mm, wall thickness or schedule to specification	Seamless or welded, high-temperature solution annealed, pickled	Reformer tubes, pigtails, convection tubing, manifolds and superheater systems	View Pipe & Tube
Round Bar	Diameter 3-300 mm, larger forged sizes and custom lengths available	Hot rolled, forged, solution annealed, peeled or machined	Furnace hardware, supports, valve parts and high-temperature fasteners	View Round Bar
Sheet & Plate	Thickness 0.5-100 mm, custom widths, lengths and cut parts	Controlled-grain solution annealed, pickled or surface finished	Furnace shells, heat shields, retorts, baffles and fabricated hot-section equipment	View Sheet & Plate
Strip & Foil	Thickness 0.02-3 mm, slit widths and coil weights to specification	Cold rolled, annealed, bright or pickled	High-temperature seals, expansion elements, shields and formed components	View Strip & Foil
Wire	Diameter 0.1-12 mm, coil, spool or straight-length supply	Cold drawn, annealed, bright or cleaned	Furnace mesh, woven components, retaining wire and fabricated hardware	View Wire
Fasteners	Standard and custom bolts, nuts, screws, studs and washers	Solution annealed, machined, rolled thread or custom finished	Petrochemical heaters, furnace assemblies and elevated-temperature equipment	View Fasteners
Fittings	ASME, EN and drawing-based elbows, tees, reducers and caps	Wrought or fabricated, solution annealed and inspected	Reformer piping, heater connections and high-temperature process lines	View Fittings
Flanges	ASME B16.5, ASME B16.47, EN or custom dimensions	Forged, solution annealed, machined and inspected	Manifolds, heater piping, pressure vessels and high-temperature connections	View Flanges
Forgings	Rings, discs, blocks, shafts and drawing-based components	Forged, high-temperature solution annealed, rough or finish machined	Tube sheets, manifolds, valve bodies, rings and pressure-containing parts	View Forgings
Welding Wire	Diameter 0.8-4.0 mm, spool, coil or straight-length supply	Clean bright finish, precision drawn and controlled chemistry	Joining Alloy 800HT, repair welding and high-temperature fabrication	View Welding Wire

Material Selection Guide

When to consider Incoloy 800HT

This guide helps buyers connect service conditions with the typical advantage of Alloy 625. Final selection should consider medium concentration, temperature, pressure, fabrication, availability and budget.

Service Requirement	Why Incoloy 800HT Helps	Common Product Form	Buyer Note
Long-term service above 593 °C	Controlled carbon, aluminum and titanium combined with coarse grains provide improved creep and rupture strength.	Pipe, tube, plate, bar, forgings and fittings	Provide the design temperature, pressure, required life and applicable construction code.
Steam and hydrocarbon reforming	The alloy combines high-temperature strength with resistance to oxidation and carburizing process atmospheres.	Catalyst tube, pigtail, manifold, flange and fitting	Confirm gas chemistry, metal temperature, pressure and thermal cycling.
Ethylene cracking equipment	Maintains useful metallurgical stability during extended exposure to high-temperature process conditions.	Convection tube, cracking tube, pigtail and return bend	Review carburization, coke formation, decoking cycles and weld-joint requirements.
Industrial heat-treatment furnaces	Provides resistance to oxidation, carburization and selected nitriding atmospheres.	Radiant tube, muffle, retort, fixture, plate and bar	Specify the furnace atmosphere, peak temperature, load and cycle frequency.
High-temperature pressure equipment	UNS N08811 provides controlled chemistry and processing for elevated allowable design stresses where code permitted.	Tube, pipe, forging, flange and plate	Verify the current ASME material listing, Code Case, allowable stress and fabrication rules.
Welded elevated-temperature assemblies	The alloy has good weldability when matched with a filler metal appropriate for the intended service temperature.	Plate, pipe, tube, fitting and fabricated assembly	Qualify the WPS and evaluate whether fabrication strain requires stress relief or renewed solution annealing.

Why Choose Us

Supply and quality support for Incoloy 800HT

For ranking traffic, buyers need more than a data sheet. This section gives clear trust signals for procurement, engineering and quality teams.

STASTM / ASME / AMS / EN

Quotation can be matched to project standards and product form specifications.

MTEN10204 3.1 MTC

Heat number, chemistry, mechanical properties and inspection records can be supplied.

QCPMI & Inspection

PMI, UT, dimensional inspection, visual inspection and packing check are available.

CSCustom Size

Cutting, machining allowance, rough machining and drawing-based supply can be arranged.

EPExport Packing

Wooden case, bundle, waterproof protection and international shipping documents.

RFFast Technical Reply

Send grade, size, standard, quantity and destination for a practical quotation route.

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FAQ

Incoloy 800HT questions from buyers

Find practical answers about procurement, standards, fabrication and industrial applications.

Incoloy 800HT is used for equipment requiring creep and stress-rupture strength during prolonged high-temperature service. Typical applications include reformer tubing, pigtails, outlet manifolds, ethylene furnace components, radiant tubes, retorts, furnace fixtures, steam superheater tubing and high-temperature heat exchangers.

Yes. UNS N08811 is the standardized designation associated with Incoloy 800HT. The alloy is also commonly identified as Alloy 800HT, Werkstoff 1.4959 or EN X8NiCrAlTi32-21.

Both alloys use controlled carbon and coarse grains for elevated-temperature strength. UNS N08811 has the narrower carbon range of 0.06-0.10%, requires aluminum plus titanium of 0.85-1.20% and receives a solution treatment at 1149 °C minimum. Certified 800HT material can generally meet N08810 chemistry, but ordinary 800H material cannot be certified as N08811 unless every additional requirement is satisfied.

We can quote plate, sheet, strip, foil, round bar, rod, wire, seamless or welded pipe and tube, fasteners, fittings, flanges, forgings and welding wire. Custom dimensions, cut pieces, machining allowance and drawing-based products can also be discussed.

Common standards include ASTM B409 for plate, sheet and strip, ASTM B408 for rod and bar, ASTM B407 or B163 for seamless pipe and tube, ASTM B514 for welded pipe, ASTM B515 for welded heat-exchanger tube, ASTM B564 for forgings and ASTM B366 for wrought fittings. The required edition and corresponding ASME specification should be stated in the purchase order.

Yes. Alloy 800HT has good weldability using properly qualified procedures. ERNiCr-3 filler is commonly used for service up to approximately 790 °C, while higher-temperature applications may require a stronger nickel-chromium-cobalt-molybdenum consumable. Filler selection must consider the actual temperature, required rupture strength, corrosion environment and governing construction code.

The minimum 1149 °C solution treatment develops a coarse austenitic grain structure, normally ASTM grain size 5 or coarser. Together with the controlled carbon, aluminum and titanium contents, this structure provides the creep and stress-rupture performance expected from UNS N08811. Excessive fabrication strain can alter that structure and may require engineering review or renewed heat treatment.

Please provide UNS N08811, product form, dimensions, quantity, applicable ASTM or ASME standard, solution-treatment and grain-size requirements, certificate type and destination. For high-temperature projects, also send the design temperature, pressure, required service life, atmosphere, drawings, welding requirements and inspection plan.

Incoloy 800HT