ASTM B407 Incoloy 800HT Pipe

1. Standard: ASTM B407, ASTM B514, ASTM B515, ASTM B829
2. Diameters: 4.0 - 1219.2 mm
3. Wall thickness: 0.3 to 50mm
4. Equivalent: UNS N08811, Din 1.4959, Incoloy 800HT

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Product Introduction

Belonging to the UNS N08811 and DIN W.Nr. 1.4959 classifications, Incoloy 800HT is a highly specialized variant of the foundational Alloy 800 series. While the base chemistry remains grounded in a balanced mix of iron (39.5% minimum), nickel (30.0% - 35.0%), and chromium (19.0% - 23.0%), the magic lies in its micro-alloying precision. HT PIPE is a incoloy 800ht pipe supplier with 15+ export experience. Contact us for more information and quotes for free!

We offers Incoloy 800HT in a variety of forms, including:

Bar
Wire
Sheet
Plate
Forgings
Pipe fittings
Flanges
Seamless & Welded pipe
Seamless Tube & Welded tube
Weld Rod

Specification

Specification Type	Standard / Designation
UNS Number	N08811
Werkstoff Number	1.4959 (also cross-referenced with 1.4876)
Seamless Pipe & Tube	ASTM B407, ASME SB407
Welded Pipe & Tube	ASTM B514, B751
Forgings & Flanges	ASTM B564, ASME SB564
Fittings	ASTM B366

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Alloy 800/800H/800HT Chemical Composition

Grade	C	Mn	Si	S	Cu	Fe	Ni	Cr	Al	Ti
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

Advanced Creep-Rupture Kinetics

In high-temperature piping systems, metals undergo gradual, permanent deformation over time under mechanical stress-a phenomenon known as creep. The unique interaction of the aluminum and titanium precipitates along the coarse grain boundaries of Incoloy 800HT prevents this micro-structural slipping. It permits significantly higher design allowable stresses than conventional alloys.

Exceptional Oxidation and Carburization Resistance

With a chromium content of up to 23%, these pipes develop a highly tenacious, self-healing chromium oxide film when exposed to air or process gases. Concurrently, the 30% - 35% nickel base safeguards the system against internal carburization and structural embrittlement, keeping the pipe ductile even during extended multi-thousand-hour thermal cycles.

Structural Resistance to Sigma Phase Embrittlement

Many competitive high-temperature stainless steels degrade over time due to the precipitation of a brittle "sigma phase" intermetallic compound between 1200℉ and 1600℉. Thanks to its high nickel concentration, Incoloy 800HT resists this structural shift, retaining excellent toughness down to cryogenic baselines.

Fabrication, Welding, and Maintenance Insights

While Incoloy 800HT behaves similarly to standard austenitic stainless steels, it exhibits unique characteristics during fabrication. It features excellent cold-forming traits, though extensive cold deformation may produce a distinct "orange peel" textured surface due to its intentionally coarse grain size.

When welding Incoloy 800HT pipes, matching composition filler metals like Inconel Filler Metal 82 (for gas tungsten arc welding) or Inconel Welding Electrode 182 (for shielded metal arc welding) are generally recommended. For applications requiring optimal creep resistance at maximum operating temperatures, specialized over-alloyed filler metals like Inconel 617 or Alloy 21-33Nb are often utilized to prevent the weld joints from acting as localized weak points under thermal stress.