A nickel-iron-cobalt alloy with additions of niobium, titanium and aluminum for precipitation hardening. The alloy combines high strength with a low and constant coefficient of thermal expansion at temperatures to about 800°F (430°C). It also has a constant modulus of elasticity and is highly resistant to thermal fatigue and thermal shock. Used in gas turbines for rings and casings.

STANDARD PRODUCT FORMS

Sheet, plate, rod, bar and forging stock.

MAJOR SPECIFICATIONS

UNS N19903

LIMITING CHEMICAL COMPOSITION, %

Ni.......36.0 – 40.0
Fe.......Remainder
Co...... 13.0 – 17.0
Al.......0.30 – 1.15
Ti.......1.00 – 1.85
Nb.....2.40 – 3.50

PHYSICAL CONSTANTS AND THERMAL PROPERTIES

Density, Ib/in³.........................................................................0.298
g/cm³......................................................................... 8.25
Melting Range, °F....................................................2405 – 2539
°C....................................................1318 – 1393
Specific Heat, Btu/lb•°F.....................................................0.105
J/kg•°C............................................................ 442
Curie Temperature, °F................................................780 – 880
°C................................................415 – 470
Coefficient of Expansion, 77 – 800°F, 10^-6 in/in •°F........4.0
25 – 427°C, μm/m •°C............. 7.2
Thermal Conductivity, Btu • in/ft²•h•°F............................ 116
W/m •°C........................................... 16.7
Electrical Resistivity, ohm •circ mil/ft................................ 379
μΩ•m...............................................0.650

TYPICAL MECHANICAL PROPERTIES

INCOLOY 907

INCOLOY 865