Incoloy 800HT Pipe Fittings Manufacturer in India

Incoloy 800HT Pipe Fittings (UNS N08811) are the quality grade of the 800 alloy series. The 'HT' designation is for alloys that must have a higher and more consistent volume fraction of gamma-prime precipitates by controlling aluminium (0.25-0.60%) and titanium (0.25-0.60%) with a minimum combined value of 0.85%, which is higher and more consistent than for 800H. Incoloy 800HT Pipe Fittings provide the highest long-term creep-rupture strength that the 800 series alloy system can
provide to the process equipment in which they are used, such as power plant steam generators operated at 700–1000 °C, direct-fired ethylene cracking furnaces and high-temperature thermal processing headers. Amardeep Steel Centre is an experienced manufacturer of Incoloy 800HT Fittings and Incoloy 800HT Pipe Fittings supplier, they stock all the Incoloy 800HT fittings with controlled grain size certificates, full chemistry trace and with EN 10204 3.1 documentation.

ASTM B366 UNS N08811 Pipe Fittings Specifications

Parameter	Details
Specification	ASTM B366 / ASME SB366
UNS No.	N08811
Werkstoff No.	1.4959
Size Range (BW)	1/2" NB to 48" NB
Schedules	SCH 10 to XXS
Grain Size	ASTM No. 5 or coarser (mandatory)
Dimension Standards	ASME B16.9, MSS SP-43, ASME B16.11
Form	Seamless & Welded; Solution Annealed
MTC	EN 10204 3.1

Types of Incoloy 800HT Pipe Fittings

Fitting	Description	Standard
Incoloy 800HT Elbow	45° / 90° LR & SR; 180° return bend	ASME B16.9
Incoloy 800HT Tee	Equal and reducing tees	ASME B16.9
Incoloy 800HT Reducer	Concentric & eccentric reducers	ASME B16.9
End Cap	Pipe end closures	ASME B16.9
Stub End	Lap joint stub ends	MSS SP-43
Socket Weld Fittings	Elbows, tees, couplings	ASME B16.11
Threaded Fittings	NPT elbows, tees, unions	ASME B16.11

Incoloy 800HT Pipe Fittings — Get Certified Stock Fast

Email info@amardeepsteel.com with your PO number, grade, and size list

Incoloy 800HT Chemical Composition

Ni	Cr	Fe (min)	Al	Ti	Al+Ti (min)	C
30–35%	19–23%	39.5%	0.25–0.60%	0.25–0.60%	0.85%	0.06–0.10%

Incoloy 800HT Mechanical Properties

UTS (MPa)	0.2% YS (MPa)	Elongation (%)	Hardness (Rb max)
517 min	207 min	30 min	90

Difference Between Incoloy 800H and 800HT

Property	Incoloy 800H	Incoloy 800HT
UNS No.	N08810	N08811
Al range (%)	0.15–0.60	0.25–0.60
Ti range (%)	0.15–0.60	0.25–0.60
Al + Ti (min %)	No combined minimum	0.85% minimum (controlled)
Creep Performance	Good	Superior (higher γ' volume fraction)

Incoloy 800HT Pipe Fittings Dimensional Tolerances

NPS	OD at Bevel ¹	ID at End ¹	Wall Thickness ²	Centre-to-End (A,B,C,M)	Overall Length L	Overall Length E	Centre-to-Centre O	Back-to-Face K	Alignment at Ends U
1/2 to 2-1/2	+1/16 / −1/32	±1/32	Min 87.5% of nominal	±1/16	±1/16	±1/8	±1/4	±1/4	±1/32
3 to 3-1/2	±1/16	±1/16	Min 87.5% of nominal	±1/16	±1/16	±1/8	±1/4	±1/4	±1/32
4	±1/16	±1/16	Min 87.5% of nominal	±1/16	±1/16	±1/8	±1/4	±1/4	±1/32
5 to 8	+1/32 / −1/16	±1/16	Min 87.5% of nominal	±1/16	±1/16	±1/4	±1/4	±1/4	±1/32
10 to 18	+1/16 / −1/8	±1/8	Min 87.5% of nominal	±3/32	±3/32	±1/4	±3/8	±1/4	±1/16
20 to 24	+1/4 / −3/32	±3/32	Min 87.5% of nominal	±3/32	±3/32	±1/4	±3/8	±1/4	±1/16

Angularity Tolerances (Off Angle)

NPS Range	Off Angle Q	Off Angle P
12 to 4	1/32	1/16
5 to 8	1/16	1/8
10 to 12	3/32	3/16
14 to 16	3/32	1/4
18 to 24	1/8	3/8

Applications of Incoloy 800HT Pipe Fittings

Power plant steam generators: superheater and reheater header fittings in fossil fuel and nuclear power units above 700 °C
Ethylene cracking: convection section piping, transfer line connections, and coil support fittings
Industrial furnaces: radiant tube assemblies, muffle liners, and heat treatment retort connections at 1000–1100 °C
Catalytic reformers: primary reformer outlet piping where Incoloy 800HT fittings exporter grade is specified by licensors
High-temperature pressure equipment: ASME Sect. VIII creep design applications per ASME allowable stress tables

Frequently Asked Questions

Q: What makes Incoloy 800HT superior to 800H for high-temperature service?

A: Incoloy 800HT (N08811) has controlled aluminium and titanium at 0.25–0.60% each (combined ≥ 0.85%), ensuring a consistent volume fraction of γ' precipitates for maximum long-term creep-rupture strength above 700 °C.

Q: What is the UNS number for Incoloy 800HT Pipe Fittings?

A: Incoloy 800HT Pipe Fittings carry UNS N08811 and Werkstoff number 1.4959, produced per ASTM B366 with grain size ≥ ASTM No. 5 in the solution-annealed condition.

Q: Can Incoloy 800HT fittings replace Incoloy 800H in service?

A: Incoloy 800HT is considered an upgraded version of 800H. 800HT fittings can directly replace 800H where code allows, and many manufacturers supply dual-certified 800H/800HT material where composition satisfies both.

Q: What is the maximum operating temperature for Incoloy 800HT Pipe Fittings?

A: Incoloy 800HT Pipe Fittings can operate up to approximately 1100 °C in oxidising atmospheres, making them suitable for the most demanding furnace and reformer piping connections.