Incoloy Alloy 800

Incoloy 800/800H/800HT Specification

Incoloy 800 is also known as Alloy 800. Its nickel-iron-chromium composition makes it useful in environments with temperatures up to 1100° F. Incoloy 800/H/HT are used in areas where resistance to corrosion and oxidation is crucial.

Incoloy 800H has the same composition as Alloy 800: a nickel-iron-chromium alloy. However, Incoloy 800H has superior resistance to creep rupture compared to Alloy 800. The increased strength results from a high temperature anneal of carbon, aluminum and titanium added into the composition. The additions serve to increase Incoloy 800 H’s strength and temperature resistance, along with resistance to carbonization and oxidation.

Incoloy 800 HT has the same chemical makeup as Incoloy 800 H but for the differences in carbon, aluminum and titanium quantities. Incoloy 800 H has more carbon, but Incoloy 800 HT is composed of more aluminum and titanium. This gives 800 HT even greater resistance to high temperatures. Incoloy 800 H/HT are recommended for temperatures exceeding 1100° F, often in instances where stainless steels are subject to crack and creep. The Incoloy alloys are commonly used in high temperature environments, such as industrial furnaces, chemical and nuclear vessels, and heat-treating equipment. Both Incoloy 800 H and 800 HT are dually certified.

Incoloy 800/800H/800HT Products Form

• Sheet
• Plate
• Bar
• Pipe & Tube (welded & seamless)
• Fittings
• Elbows, tees, stub-ends, returns, caps, crosses, reducers, pipe nipples. etc.
• Wire

Applications for Incoloy 800/800H/800HT

• Heat exchangers and process piping
• Chemical processing
• Carburizing fixtures and retorts
• Oil and gas industries
• Nuclear and power industries
• Commercial Gas Turbines
• Furnace components
• Food Processing
• Electric range heating-element sheathing
• Chemical Processing
• Cryogenic Storage Tanks
• Ammonia effluent coolers
• Power generation industries
• Nuclear reactors
• Gas turbines engines
• Pressure vessels

Equivalents of Incoloy 800/800H/800HT

Standard	Incoloy 800	Incoloy 800H	Incoloy 800HT
UNS	N08800	N08810	N08811
WERKSTOFF NR.	1.4876	1.4958 / 1.4876	1.4859 / 1.4876
EN	X10NiCrAlTi32-20	X5NiCrAlTi31-20	X8NiCrAlTi32-21
BS	NA 15	NA 15(H)	NA 15(HT)
OR	XH32T	XH32T	XH32T
GOST	ЭИ670	ЭИ670	ЭИ670
JIS	NCF 800	NCF 800H	NCF 800HT
AFNOR	Z8NC32-21	Z8NC33-21	–

Chemical Composition – Incoloy 800 / 800H / 800HT

ELEMENT	INCOLOY 800	INCOLOY 800H	INCOLOY 800HT
NI	30.0 – 35.0	30.0 – 35.0	30.0 – 35.0
CR	19.0 – 23.0	19.0 – 23.0	19.0 – 23.0
FE	39.5 min	39.5 min	39.5 min
MN	1.5 max	1.5 max	1.5 max
C	0.10 max	0.05 – 0.10	0.06 – 0.10
CU	0.75 max	0.75 max	0.75 max
SI	1.0 max	1.0 max	1.0 max
S	0.015 max	0.015 max	0.015 max
AL	0.15 – 0.60	0.15 – 0.60	0.15 – 0.60
TI	0.15 – 0.60	0.15 – 0.60	0.15 – 0.60

* UNS N08811 : Al + Ti = 0.85 – 1.20

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

Physical Properties

Density	0.287 lb/in3 / 7.94 g/cm3
Melting Point	2475 – 2525 °F/ 1357 – 1385 °C
Specific Heat  @ 70°F	0.11 BTU/lb-°F (32 – 212°F) 460 J/kg-°K (0 –100°C)
Thermal Conductivity @ 212°F	10.6 BTU/hr/ft2/ft/°F 18.3 W/m-°K
Elastic Modulus	28.5 x 106 psi 196.5 GPa
Electrical Resistivity	59.5 Microhm-in at 68°F 99 Microhm-cm at 20°C
Annealing	983 – 1038 °C / 1800 – 1900 °F
Quench	Rapid Air
Permeability @ 70°F Annealed	1.014 (200 Oersted)
Curie Temperature	-115 °C/ -175 °F

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.

Heat Treatment

The grade has high rate of work hardening. Hence, after cold working to remove brittleness, the grade needs to annealed. Annealing is done by heating the grade about 980°C for about 15 minutes, and then air cooling.

Hot working

INCOLOY alloy 800 can be hot worked at temperature ranges of 871-1232°C (1600-2250°F).

Cold working

Cold working may be done on the alloy using standard tooling.

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.

Welding

The grade can be readily welded by common welding techniques like gas tungsten arc welding, shielded metal arc welding, metal inert gas welding, etc. Post-weld annealing might not be required. The grade can be appropriately brushed for impurities and heat tint is removed after welding.

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.