| Element | Min % | Max % |
| Fe | 53.00 nominal | |
| Ni | 29.00 nominal | |
| Co | 17.00 nominal | |
| Mn | – | 0.50 |
| Si | – | 0.20 |
| C | – | 0.04 |
| Al | – | 0.10 |
| Mg | – | 0.10 |
| Zr | – | 0.10 |
| Ti | – | 0.10 |
| Cu | – | 0.20 |
| Cr | – | 0.20 |
| Mo | – | 0.20 |
Density
8.16 g/cm³ | 0.295 lb/in³
Melting Point
1450°C | 2640°F
Inflection Point
450°C | 840°F
Thermal Conductivity
16.7 W/m•°C | 116 btu•in/ft2•h°F
Coefficient of Expansion
6.0 µm/m °C (20 – 100°C) 4.6 – 5.2 µm/m °C (20 – 400°C) | 3.3 x 10-6 in/in °F (70 – 212°F) 2.6 – 2.9 x 10-6 in/in °F (70 – 752°F)
HEAT TREATMENT OF FINISHED PARTS THE ALLOY IS USUALLY SUPPLIED AND USED IN THE ANNEALED CONDITION (RESIDUAL COLD WORK DISTORTS THE COEFFICIENTS OF THERMAL EXPANSION). ANNEALING TIMES MAY VARY DUE TO SECTION THICKNESS. OXIDIZING TIME AND TEMPERATURE TO BE SELECTED DEPENDING ON REQUIRED OXIDE THICKNESS.
| Type | Temperature | Time (Hr) | Cooling | ||
| °C | °F | ||||
| Anneal | 850 – 1000 | 1560 – 1830 | 0.5 | Air or water | |
| To prepare for glass to metal sealing | Decarburization | 900 – 1050 | 1650 – 1920 | 1 | Air or water |
| If a metal oxide interface is required (time and temperature depend on required oxide thickness) |
Oxidize | 600 – 1000 | 1110 – 1830 | 1 | Air |
PROPERTIES
| Condition | Approx. tensile strength | Approx. operating temperature | ||
| N/mm² | ksi | °C | °F | |
| Annealed | 450 – 550 | 65 – 80 | up to +400 | up to +750 |
| Hard Drawn | 700 – 900 | 102 – 131 | up to +400 | up to +750 |