General
Properties
Nickel-Iron Alloy with a Very Low Coefficient of Thermal Expansion from Cryogenic Temperatures to 400ºF (200ºC)
SSC INVAR 36 (UNS K93603) is an austenitic nickel-iron alloy containing 36% nickel. It has an extremely low coefficient of thermal expansion from -418ºF (-250ºC) to 392ºF (200ºC). The alloy has good fatigue and mechanical properties at cryogenic temperatures. It exhibits moderately high strength along with good ductility and toughness. These properties along with good fabrication characteristics make SSC INVAR 36 ideal for applications requiring precise dimensional stability.
SC INVAR 36 can be hot
and cold worked, machined, and formed. Fabrication processes are similar to austenitic stainless steels. The alloy can be welded using filler wire with expansion rates similar to those of the base metal.
SSC INVAR 36 resists corrosion in dry atmospheres at room temperature. In humid or moist atmospheres, corrosion can occur in the form of rust.
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Stock Thicknesses
SSC INVAR 36 is available from our stock of Stainless Steel and Nickel Alloy Plate. We maintain the largest inventory of specialty plate in North America – over 16 million pounds! We stock SSC INVAR 36 in thicknesses from .250" (6.3mm) through 4.00" (101.6mm).
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Applications
SSC INVAR 36 is utilized extensively in other industrial applications where dimensional stability is essential.
- Tooling and Dies for Aerospace Composite Tooling
- Thermoset Epoxy Systems
- Resin Transfer Molded Tools
- Cryogenic Components and Piping
- Laser Components
- Liquified Natural Gas (LNG)Marine fixtures and fasteners
- Production and Storage Equipment
- LNG Tanker Membranes
- Marine Components
- Wind Turbines
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Standards/Material Certifications
ASTM......................... F1684-06
BOEING..................... D-33028-2
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Chemical
Analysis
| NI |
Cr |
C |
Mn |
Si |
Co |
| 36.00% |
0.25% max |
0.05% max |
0.60% max |
0.40% max |
0.50% max |
| P |
S |
AI |
Mg |
Zr |
Ti |
Fe |
| 0.015% max |
0.015% max |
0.10% max |
0.10% max |
0.10% max |
0.10% max |
Balance |
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Physical
Properties
| Density |
Melting Point |
Specific Heat |
| 0.293 lb/in3 |
2606ºF |
0.123 BTU/lb-ºF |
| 8.11 g/cm3 |
1430ºC |
515 J/kg-ºC |
Typical Thermal Expansion of SSC INVAR 36
| Temperature Range |
Total Expansion |
Mean Linear Coefficient |
| °C |
°F |
(10-3) |
(10-6/°C) |
(10-6/°F) |
| -200 - 20 |
-328 - 68 |
-0.33 |
1.5 |
0.8 |
| -100 - 20 |
-148 - 68 |
-0.16 |
1.3 |
0.7 |
| 20 - 100 |
68 - 212 |
0.12 |
1.5 |
0.8 |
| 20 - 150 |
68 - 302 |
0.26 |
2.0 |
1.1 |
| 20 - 200 |
68 - 392 |
0.47 |
2.6 |
1.4 |
| 20 - 250 |
68 - 482 |
0.80 |
3.5 |
1.9 |
| 20 - 300 |
68 - 572 |
1.54 |
5.5 |
3.1 |
| 20 - 350 |
68 - 662 |
2.37 |
7.2 |
4.0 |
| 20 -400 |
68 - 752 |
3.19 |
8.4 |
4.7 |
| 20 - 450 |
68 - 842 |
4.01 |
9.3 |
5.2 |
| 20 - 500 |
68 - 932 |
4.85 |
10.1 |
5.6 |
Electrical Resistivity
| Temperature |
Microhm cm (ohm.circ mil/ft) |
| °C |
°F |
| 20 |
68 |
80 (481) |
| 100 |
212 |
86 (517) |
| 200 |
392 |
97 (583) |
| 300 |
572 |
105 (632) |
| 400 |
752 |
111 (668) |
| 500 |
932 |
117 (704) |
| 600 |
1112 |
121 (728) |
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Mechanical
Properties
Typical Room Temperature Mechanical Properties, Mill Annealed
| Temperature |
Tensile Strength |
Yield Strength
(0.2% Offset) |
Elongation
on 50 mm
(2 inch) % |
Reduction of
Area % |
| °C |
°F |
(MPa) |
psi |
(MPa) |
psi |
| 20 |
68 |
490 |
71.0 |
240 |
35.0 |
42 |
70 |
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