The differences between Incoloy 800, 800H, and 800HT plates

Incoloy 800 plate is a basic alloy used in high-temperature environments; 800H alloy plate improves creep strength through the addition of carbon (0.05-0.10%) and heat treatment; while 800HT plate further optimizes the aluminum/titanium content (0.85-1.20%) and carbon content (0.06-0.10%), resulting in superior creep/rupture strength at extremely high temperatures (above 600°C/1100°F). Of these, 800HT plate offers the best performance in demanding environments, although both 800H/HT plates are typically dual-certified and exhibit better high-temperature performance than the basic 800 alloy plate.

What are the specifications of Incoloy 800 HT?

The chemical composition of INCOLOY 800HT alloy falls within the range of the 800H alloy, but with a narrower compositional range and requiring heat treatment at a minimum of 2100°F (1149°C). Its carbon content is 0.06% to 0.10% (compared to 0.05% to 0.10% for 800H alloy), and the total aluminum and titanium content is 0.85% to 1.20% (compared to 0.30% to 1.20% for 800H alloy).

Incoloy 800 plate is a sheet material rolled from a nickel-iron-chromium austenitic alloy (Incoloy 800/800H/800HT). Its core characteristics include excellent creep resistance, carburization resistance, and high-temperature oxidation resistance at temperatures up to approximately 815°C, while maintaining good strength and thermal stability. It is designed for critical structural components that require long-term exposure to high-temperature corrosive atmospheres and mechanical stress, such as high-temperature heat treatment furnaces, petrochemical cracking units, industrial heaters, and nuclear power steam generators. It is a specialized high-performance plate material for addressing high-temperature oxidation and thermal fatigue problems.

Incoloy 800H plate is a sheet material rolled from Incoloy 800H alloy. Its core characteristics are achieved through a higher carbon content (0.05-0.10%) and specific solution heat treatment, providing superior creep resistance, carburization resistance, and high-temperature oxidation resistance at temperatures up to approximately 815°C, while maintaining excellent high-temperature strength and structural stability. It is designed for pressure-bearing structural components in extreme environments requiring long-term exposure to high temperatures, high pressures, and thermal cycling, such as petrochemical cracking furnaces, high-temperature heat exchangers, industrial heaters, and nuclear power steam generators. It is a key plate material for high-temperature creep-resistant applications.

Incoloy 800HT plate is a sheet material rolled from Incoloy 800HT alloy. Its core characteristics are achieved through precise control of carbon, aluminum, and titanium content and stabilization treatment, providing optimal creep resistance, carburization resistance, and high-temperature oxidation resistance at temperatures up to approximately 815°C, while possessing extremely high high-temperature strength and long-term stability. It is designed for pressure-bearing structural components in extreme environments requiring long-term exposure to high temperatures, high pressures, and severe thermal cycling, such as petrochemical cracking furnaces, high-temperature heat exchangers, industrial heaters, and nuclear power steam generators. It is a top-tier plate material choice for high-temperature creep and fatigue resistance applications.

800/800H/800HT/825 Incoloy Plates Equivalent Grades

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

Specification of Incoloy 800/800H/800HT/825 Sheets

Incoloy Sheets and Plates Specification : ASTM B168 / ASME SB168
Dimension Standard : JIS, AISI, ASTM, GB, DIN, EN, etc
Width : 1000mm, 1219mm, 1500mm, 1800mm, 2000mm, 2500mm, 3000mm, 3500mm, etc
Length : 2000mm, 2440mm, 3000mm, 5800mm, 8000mm, etc
Thickness : 0.3 mm to 120 mm
Form : Coils, Foils, Rolls, Plain Sheet, Shim Sheet, Perforated Sheet, Chequered Plate, Strip, Flats, Blank (Circle), Ring (Flange) etc.
Surface Finishing : Hot rolled plate (HR), Cold rolled sheet (CR),2B, 2D, BA, NO.1, NO.4, NO.8, 8K, mirror, Chequered, embossed, hair line, sand blast, Brush, etching, SATIN (Met with Plastic Coated) etc.

Chemical Composition of Incoloy 800/800H/800HT/825 Plates

Grade	C	Mn	Si	S	Cu	Fe	Ni	Cr	Al	Ti
800	0.10 max	1.50 max	1.00 max	0.015 max	0.75 max	39.50 min	30.00 – 35.00	19.00 – 23.00	0.15 – 0.60	0.15 – 0.60
800HT	0.05 – 0.10	1.50 max	1.00 max	0.015 max	0.75 max	39.50 min	30.00 – 35.00	19.00 – 23.00	0.15 – 0.60	0.15 – 0.60
800HT	0.06 – 0.10	1.50 max	1.00 max	0.015 max	0.75 max	39.50 min	30.00 – 35.00	19.00 – 23.00	0.15 – 0.60	0.15 – 0.60
Alloy 825	0.05 max	1.0 max	0.5 max	0.03 max	1.5 – 3.0	22.0 min	38.0 – 46.0	19.5 – 23.5	0.2max	0.6 – 1.2