Nickel Alloys Incoloy Alloy 800 N08800
Austral Wight Speciality Metals

 Product Data Sheet  Nickel Alloys

Alloy 800™, 800H™, 800HT™  UNS-N08800, N08810, N08811

Incoloy® Alloy 800™ is widely used in equipment that must have high strength and resistance to oxidation, carburisation and other harmful effects of high temperature exposure. For service requiring optimum creep and rupture properties, Incoloy 800H or 800 HT are used. The high contents of nickel and chromium in the alloys also give good corrosion resistance.

Chemical Composition

ASTM B407 – Seamless Pipe & Tube

Element Incoloy 800 Incoloy 800H Incoloy 800HT
Nickel
30.00-35.00 30.00-35.00 30.00-35.00
Chromium
19.00-23.00 19.00-23.00 19.00-23.00
Iron
39.50 min 39.50 min 39.50 min
Carbon
0.10 max 0.05-0.10 0.06-0.10
Aluminium
0.15-0.60 0.15-0.60 0.25-0.60
Titanium
0.15-0.60 0.15-0.60 0.25-0.60
Aluminium + Titanium
0.30-1.20 0.30-1.20 0.85-1.20
ASTM Grain Size
Not Specified 5 or Coarser

Specified Minimum Mechanical Properties

ASTM B407 – Seamless Pipe & Tube

Yield Strength
Tensile Strength
Elongation
MPa
MPa
%
Incoloy 800, 800H, 800HT Hot Finished, Annealed 170 450 30
Incoloy 800 Cold Worked, Annealed 205 520 30

Incoloy 800 is a solid solution strengthened alloy of nickel, chromium and iron with small additions of aluminium and titanium. Incoloy 800H and Incoloy 800HT are developments of Incoloy 800, which give better performance at high temperature. ASME design codes give significantly higher design strengths for Incoloy H and HT than Incoloy 800, and allow their use to higher temperatures. AS1210 prequalifies Incoloy 800 for use to 800°C. ASME specifications allow the use of Incoloy 800 to 815°C, and of Incoloy 800H and 800HT to 982°C.

Typical Applications

Thermal processing equipment in industrial applications, such as baskets, trays, and fixtures. In chemical or petrochemical processing it is used for heat exchangers and piping systems in nitric acid media, especially where resistance to chloride stress corrosion cracking is required.

Description

Incoloy 800/800H/800HT are solid solution nickel chromium iron alloys with small additions of aluminium and titanium to improve corrosion and oxidation resistance. They are used for high temperature service, where resistance to oxidation and carburisation are required. For optimum stress rupture properties, or for pressure vessel service above 815°C, Incoloy 800H or Incoloy 800HT should be used.

Availability

Austral Wright Metals can supply these alloys as plate, sheet and strip, rod and bar, seamless and welded tube and pipe, fittings, condenser & heat exchanger tube, forgings and forging stock.

Oxidisation Resistance

The chromium and nickel contents of the alloy give excellent oxidation resistance, good resistance to carburisation and resistance to sulphidation at low concentrations of oxidising and reducing sulphur. The alloy also has reasonable resistance to nitridation in cracked ammonia, but falls short of the resistance of Inconel 600.

Variation of Tensile Properties with Temperature

Nickel Alloys Incoloy Alloy Incoloy Alloy 800 N08800

Variation of tensile properties with temperature for Incoloy 800

Variation of tensile properties with temperature for Incoloy 800HT

Corrosion Resistance

Incoloy 800/800H/800HT is generally free from both chloride stress corrosion cracking and intergranular corrosion caused by sensitisation. The alloy can be used in sea water. Incoloy 800/800H/800HT has resistance to acids similar to austenitic stainless steels. It has excellent resistance to both oxidising and non oxidising salts, except for halide salts, where pitting may occur. Please consult Austral Wright Metals for advice on your specific application.

Fabrication

Incoloy 800/800H/800HT can be readily hot worked. Forging is finished above 870°C, and air cooled. The work is then solution annealed. The alloys can be cold formed similarly to stainless steel but deformation forces are higher.

Machinability

Incoloy 800/800H/800HT are “C” class alloys, difficult to machine. Heavy machines, sharps, slow speeds and deep cuts to remove the work hardened layer are needed.

Weldability

Incoloy 800/800H/800HT are readily welded by the SMAW (manual), GMAW (MIG), GTAW (TIG) and SAW processes. Preheat or post heat and post weld heat treatment are not needed. Contamination of the weld pool should be prevented. Argon is used as the shielding gas.

Welding Consumables

Incoloy 800 Incoloy 800HT
SMAW GTAW, GMAW Cored Wire SMAW GTAW, GMAW
Recommended INCO WELD A Inconel FM 82 INCO CORED 82DH Inconel WE 117 Inconel FM 617
Higher Strength Inconel WE 112 Inconel FM 625 INCO CORED 625DH Inconel WE 117 Inconel FM 617
Better Corrosion Resistance Inconel WE 182 Inconel FM 82 INCO CORED 82DH Inconel WE 117 Inconel FM 617

Heat Treatment

Incoloy 800 is solution annealed at 980°C, then rapidly cooled. Appreciable grain growth will occur if this temperature is exceeded. Incoloy 800H and 800HT are annealed at is 1150 – 1200°C to grow the grain size to ASTM 5.

Equivalent Specifications

Country Body Grade
USA UNS N08800
France AFNOR Z 8 NC 32.21
GB BS NA 15
Germany DIN 1.4876

Physical Properties

Property
Metric Units
Density
7,940 kg/m³ @ 20°C
Melting Range
1357-1385°C
Electrical Resistivity
0.989 micro-ohm . m @ 20°C
Specific Heat
460 J/kg . °C @ 20°C
Mean Coefficient of Expansion
14.4 x 10-6 / °C @ 20°C
Thermal Conductivity
11.5 W / m . °C @ 20°C
Curie Temperature
-115°C
Modulus of Elasticity
Tension
196.5 GPa @ 20°C
Torsion
73.4 GPa @ 20°C
Poisson’s Ratio
0.339 @ 20°C
Magnetic Permeability
1.014 @ 200 Oe

ASTM Product Specifications

Specification Title
B163
Seamless Nickel and Nickel Alloy Condenser and Heat Exchanger Tubes
B366
Factory Made Wrought Nickel and Nickel Alloy Fittings
B407
Nickel Iron Chromium Alloy Seamless Pipe and Tube
B408
Nickel Iron Chromium Alloy Rod and Bar
B409
Nickel Iron Chromium Alloy Plate, Sheet and Strip
B514
Welded Nickel Iron Chromium Alloy Pipe
B515
Welded UNS N08120, N08800, N08810 and UNS N08811 Alloy Tubes
B564
Nickel Alloy Forgings
B751
General Requirements for Nickel and Nickel Alloy Welded Tube
B775
General Requirements for Nickel and Nickel Alloy Welded Pipe
B829
General Requirements for Nickel and Nickel Alloy Seamless Pipe and Tube
The technical advice and recommendations made in this Product Data Sheet should not be relied or acted upon without conducting your own further investigations, including corrosion exposure tests where needed. Please consult current editions of standards for design properties. Austral Wright Metals assumes no liability in connection with the information in this Product Data Sheet. Austral Wright Metals supplies a comprehensive range of stainless steels, copper alloys, nickel alloys and other high performance metals for challenging service conditions. Our engineers and metallurgists will be pleased to provide further data and applications advice.

 

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