A nickel‑iron Invar 36 alloy offering ultra‑low thermal expansion for cryogenic, tooling and precision engineering uses.
Alloy 36, or Invar 36, is a 36% nickel–iron alloy specifically developed for applications requiring minimal thermal expansion. It maintains nearly constant dimensions from cryogenic temperatures up to around 260°C, making it ideal for precision instruments, cryogenic systems, and composite tooling.
The alloy’s low coefficient of thermal expansion (CTE) and high dimensional stability make it one of the most relied-upon materials for high-precision assemblies and environments with rapid or extreme temperature changes.
We stock alloy 36 in a variety of product forms to suit different applications and fabrication methods, including plate, round bar, sheet, and welding wire. To view available sizes and submit an enquiry, use the dropdown selector below.
The composition of Alloy L605/25 delivers high-temperature resilience and superior corrosion and oxidation resistance.
| % | Ni | Fe | Mo | C | Cu | Mn | Si | P | S | Cr |
|---|---|---|---|---|---|---|---|---|---|---|
| Min | 35 | - | - | - | - | - | - | - | - | - |
| Max | 37 | Balance | 0.5 | 0.1 | 0.5 | 0.6 | 0.35 | 0.025 | 0.025 | 0.5 |
Alloy 36 is known for its very low CTE, mechanical strength, and toughness at cryogenic and moderately elevated temperatures.
Originally developed under the trade name Invar® (a contraction of "invariable"), Alloy 36 has become the industry standard for low expansion nickel-iron alloys.
Its performance is unmatched in temperature-sensitive applications, especially those involving cryogenics, thermal cycling, and tight tolerances.
Processing & Fabrication Notes:
| Mechanical & Physical Properties | 195.6°C | 21.1°C | 93.3°C | 148.9°C | 204.4°C | 315.6°C | 371.1°C | 537.8°C | 648.9°C |
|---|---|---|---|---|---|---|---|---|---|
| Ultimate Tensile Strength /MPa | - | 490 | 430 | - | 430 | 410 | 350 | 290 | 210 |
| 0.2% Yield Strength /MPa | - | 290 | 240 | - | 110 | 93 | 93 | 93 | 77 |
| Reduction of area % | - | 70 | 70 | - | 70 | 70 | 70 | 69 | 67 |
| Elongation % | - | 42 | 42 | - | 45 | 48 | 53 | 59 | 68 |
| Coefficient of Thermal Expansion /µm/m°C | 1.44 | - | 1.44 | 1.98 | 2.52 | 5.58 | 8.46 | 10.08 | - |
| Temperature,°C | 20°C | 100°C | 200°C | 300°C | 400°C | 500°C | 600°C |
|---|---|---|---|---|---|---|---|
| Ultimate Tensile Strength, ksi | 71 | 62 | 62 | 59 | 51 | 42 | 30 |
| 0.2% Yield Strength, ksi | 35 | 26 | 16 | 13 | 13 | 13 | 11 |
| Elongation, % | 42 | 43 | 45 | 48 | 53 | 59 | 68 |
Due to its dimensional stability and low thermal expansion, Alloy 36 is used across industries that require precision and structural reliability under thermal stress.
Liquid gas storage, vacuum chambers, liquefied natural gas (LNG) systems
Aircraft part moulds, wind turbine blade tooling
Laser systems, gyroscopes, timing devices, optical equipment
Lead frames, shadow masks, mobile antenna components
Satellite systems, thermal shields, measurement equipment
Scales, strain gauges, dimensional reference standards
Its non-expanding nature prevents warping or stress distortion, ensuring precise performance over time.
Alloy 36 is used in precision instruments, cryogenic storage, aerospace moulding tools, and industrial measurement devices due to its minimal thermal expansion.
Yes, it is magnetic at room temperature but loses magnetism near its Curie point (~230–280°C).
CTE is approximately 1.2–1.5 µm/m·°C from −100°C to +100°C, making it one of the lowest among commercial alloys.
They are the same material. “Invar” is a trademarked name, but both refer to a 36% nickel–iron alloy with low expansion.
NeoNickel supplies Alloy 36 in sheet, plate, round bar, and welding wire.
Need precision-grade Alloy 36 sheet, bar, or plate for your next project? NeoNickel is a trusted Alloy 36 supplier across Europe, offering expert support and fast delivery. Request a quote or speak with one of our materials specialists today.
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