Alloy 800 / 800H / 800HT: Premium Nickel-Iron-Chromium Alloys for High-Temperature Industrial Service
Alloy 800 / 800H / 800HT: Premium Nickel-Iron-Chromium Alloys for High-Temperature Industrial Service
Alloy 800 series alloys remain highly recognized by manufacturers of petrochemical facilities, heat treatment furnaces, energy equipment and high-temperature heat exchangers. As well-established wrought nickel-iron-chromium grades, they deliver reliable oxidation resistance, superior carburization resistance and stable mechanical properties under prolonged high-temperature exposure. They are the preferred material for projects with strict requirements on material stability and fabricability. Compared with conventional austenitic stainless steels, Incoloy 800 is mainly designed for service temperatures not exceeding 1100°F, while Alloys 800H and 800HT are the standard choices for operating temperatures above 1100°F, especially for service conditions demanding outstanding creep and stress rupture resistance. Thanks to its balanced chemical composition, this nickel-iron-chromium alloy delivers exceptional resistance to carburizing, oxidizing and nitriding environments. Unlike many stainless…
Alloy 800 series alloys remain highly recognized by manufacturers of petrochemical facilities, heat treatment furnaces, energy equipment and high-temperature heat exchangers. As well-established wrought nickel-iron-chromium grades, they deliver reliable oxidation resistance, superior carburization resistance and stable mechanical properties under prolonged high-temperature exposure. They are the preferred material for projects with strict requirements on material stability and fabricability.
Compared with conventional austenitic stainless steels, Incoloy 800 is mainly designed for service temperatures not exceeding 1100°F, while Alloys 800H and 800HT are the standard choices for operating temperatures above 1100°F, especially for service conditions demanding outstanding creep and stress rupture resistance. Thanks to its balanced chemical composition, this nickel-iron-chromium alloy delivers exceptional resistance to carburizing, oxidizing and nitriding environments. Unlike many stainless steels that suffer embrittlement after long-term exposure to 1200–1600°F, Incoloy 800HT maintains its ductility and avoids brittle failure even under prolonged service within this temperature window. Like other nickel-chromium alloys, 800HT boasts excellent cold workability. Severe cold forming will generate a characteristic wavy surface texture known as the “orange peel” effect, which originates from the material’s grain structure. Incoloy 800HT is compatible with all conventional welding processes applicable to stainless steel grades.
Alloy 800 / 800H / 800HT Grade Comparison Table
Item
Alloy 800
Alloy 800H
Alloy 800HT
UNS Designation
N08800
N08810
N08811
Alloy Category
Standard Ni-Fe-Cr wrought alloy
Creep-strengthened high-temperature alloy
Thermally stabilized high-temperature alloy
Core Characteristic
Balanced general high-temperature performance
Enhanced creep & stress rupture strength
Superior long-term thermal microstructure stability
Typical Service Scenario
General medium & high-temperature static service
Long-term high-temperature load-bearing service
Severe continuous high-temperature working conditions
Typical Chemical Composition (Weight %)
Note: All listed figures represent standard composition ranges. Final chemical analysis shall comply with corresponding ASTM / ASME specifications and official Mill Test Certificates (MTC).
Element
Alloy 800
Alloy 800H
Alloy 800HT
Nickel (Ni)
30.0–35.0
30.0–35.0
30.0–35.0
Chromium (Cr)
19.0–23.0
19.0–23.0
19.0–23.0
Iron (Fe)
Min. 39.5
Min. 39.5
Min. 39.5
Carbon (C)
Max. 0.10
0.05–0.10
0.06–0.10
Manganese (Mn)
Max. 1.50
Max. 1.50
Max. 1.50
Silicon (Si)
Max. 1.00
Max. 1.00
Max. 1.00
Sulfur (S)
Max. 0.015
Max. 0.015
Max. 0.015
Copper (Cu)
Max. 0.75
Max. 0.75
Max. 0.75
Aluminum + Titanium (Al+Ti)
0.15–0.60
0.15–0.60
0.15–0.60
Incoloy 800 Series Applicable Industry Specifications
Product Form
Governing Standard
Seamless Pipe & Tube
ASTM B163 / ASME SB163
Seamless Heat Exchanger Tube
ASTM B407 / ASME SB407
Plate, Sheet & Strip
ASTM B409 / ASME SB409
Wrought Pipe Fittings
ASTM B366 / ASME SB366
Core Performance Advantages
Performance Item
Technical Description
High-Temperature Oxidation Resistance
Forms dense, adherent protective oxide scale to resist oxidation under sustained high heat
Carburization Resistance
Resists carbon infiltration, ideal for heat treatment furnaces and carburizing equipment
Creep & Stress Rupture Performance
Alloy 800H and 800HT deliver markedly higher long-term creep strength than standard Alloy 800
Microstructural Stability
Minimal grain deterioration and property degradation during prolonged thermal cycling
Fabricability
Excellent hot & cold forming performance, compatible with all mainstream welding processes
Typical Industrial Applications
Industry Sector
Representative Components
Petrochemical
High-temperature process piping, reactor shells, heat exchanger bundles
Alloy grade, dimensional size, heat lot number, production batch, net weight
Supplied Documents
Full Mill Test Certificates, third-party inspection reports, complete traceability records
In what forms is Incoloy® 800H/HT available at C&N Hongcheng?
Plate
Bar
Pipe & Tube (welded & seamless)
Fittings
Elbows, tees, stub-ends, returns, caps, crosses, reducers, pipe nipples. etc.
Alloy 800, 800H and 800HT are mature, widely adopted nickel-iron-chromium alloys for severe high-temperature industrial environments. Their integrated strengths in oxidation resistance, anti-carburization property, long-term structural stability and excellent machinability make them a reliable technical solution. We support customized dimensional fabrication and full inspection documentation for all industrial high-temperature projects.contact C&N for a quote today.
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