Materials / Superalloy

Incoloy 800H

UNS
N08810
W.Nr
1.4958
EN
X8NiCrAlTi32-21

The controlled-carbon, coarse-grain version of Incoloy 800, specified where creep and rupture strength at high temperature are the governing properties.

Composition

Chemical composition limits, per cent by weight
ElementMinMax
Ni 30.0 35.0
Cr 19.0 23.0
Fe 39.5
C 0.05 0.10
Al 0.15 0.60
Ti 0.15 0.60
Al+Ti 0.30 1.20
Mn 1.5
Cu 0.75

Per cent by weight, to the governing standard.

Nominal composition
  • Fe46.5
  • Ni32.5
  • Cr21.0

Per cent by weight, at the midpoint of each specified window. Elements given only as a maximum have no midpoint to take, so they sit inside the balance rather than being estimated; trace elements below 0.5 % are not shown. Indicative only; the composition table above and the governing standard are what define the limits.

Mechanical

Tensile strength, min
450 MPa
Yield strength (0.2%), min
170 MPa
Elongation, min
30 %
Grain size
ASTM No. 5 or coarser

Standards by form

Governing standard for each product form
Plate, sheet & strip ASTM B409
Pipe & tube ASTM B407
Bar & rod ASTM B408
Forgings ASTM B564

Where it is specified

  • Sustained service above 600 °C — furnace tubing, heat treatment fixtures, petrochemical piping
  • Creep and stress-rupture strength well beyond standard 800
  • Resists carburisation and oxidation in cyclic heat

800H is 800 only if carbon and grain size both hold

800H is Incoloy 800 only if two things hold: carbon inside the narrow 0.05–0.10 % band, and grain size ASTM 5 or coarser after a high-temperature anneal. Standard 800 supplied against an 800H order will pass a chemistry-only check on most elements and then creep at temperature. This is the substitution that certificates hide best.

What we specify and check

  • Carbon verified against the 0.05–0.10 % band, not merely against a maximum
  • Grain size determination, which a chemistry-only certificate will not cover
  • Annealing temperature records demanded
  • PMI for Al+Ti against the 0.30–1.20 % window

We commission an accredited independent laboratory to test the heat before the material leaves China. You will receive that report unedited, whether it passes or not.

Request Incoloy 800H

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