800H/AT

800H/AT

Incoloy 800H/AT is an austenitic heat resistant alloy designed for high temperature structural applications. The strength of 800H/AT is achieved by controlled levels of carbon, aluminum and titanium along with a 2100°F minimum anneal to achieve a grain size of ASTM 5 or coarser.

800H/AT is commonly welded using RA82 (ERNiCr-3) bare wire for applications under 1450°F. RA330-04 (N08334) bare wire offers a closer match of thermal expansion coefficient, and somewhat higher strength. For maximum strength alloy 617 (ERNiCrCoMo-1) bare wire or 117 (ENiCrCoMo-1) covered electrodes are suggested. To avoid possible stress relaxation grain boundary cracking of N08811 in applications above 1000°F the welded fabrication may be heated 1650°F for about one hour per inch of thickness or 30 minutes minimum then air cooled.

Chemistry

 CrNiMnSiAlTiAl +TiCCuPSFe
MIN 19.0 30.0 - - 0.15 0.15 0.85 0.06 - - - 39.5
MAX 23.0 35.0 1.5 1.0 0.6 0.6 1.2 0.1 0.75 0.045 0.015 -

Specifications

ASME SB 407 Code Case 1325ASME SB 408ASME SB 409
ASTM B 407ASTM B 408ASTM B 409
UNS N08810UNS N08811
W. Nr./EN 1.4958W. Nr./EN 1.4959

Inventory

800H/AT Coil, 800H/AT Plate, 800H/AT Sheet, 800H/AT Welding Products

Common Trade Names

800H, Incoloy® 800, Alloy 800

Features

  • High design stresses for ASME Section VIII applications to 1650°F
  • Useful oxidation resistance through 1800°F
  • Resistant to chloride ion stress corrosion cracking

Applications

  • Nitric acid catalyst supports
  • Reformer outlet pigtails and manifolds
  • Heat exchangers
  • Pressure vessels
  • Dampers

Physical Properties

Density: 0.287 lb/in3
Melting Point: 2475 - 2525°F

Temperature, °F 70 1400 1600 1800
Coefficient* of Thermal Expansion, in/in°F x 10-6 - 9.9 10.2 -
Thermal Conductivity
Btu • ft/ft2 • hr • °F
6.7 13.8 15.1 17.8
Modulus of Elasticity, Dynamic psi x 106 28.5 21.1 19.2 -

* 70°F to indicated temperature.

Mechanical Properties

Representative Tensile Properties

Temperature,°F 70 1000 1200 1400 1600 1800
Ultimate Tensile Strength, ksi 77 63.5 55.7 32.3 18.6 10.2
0.2% Yield Strength, ksi 29 16.5 14.8 14.4 11.6 8.9
Elongation, % 52 51 50 78 120 120

Typical Creep- Rupture Properties

Temperature, °F 1400 1600 1800
Minimum Creep 0.0001%/Hour, ksi 6.0 3.6 1.05
10,000 Hour Rupture Strength, ksi 7.3 3.5 1.2

INCONEL® and INCOLOY® are registered trademarks of Special Metals (PCC)