Invar 36

Invar 36 Nickel Iron Alloy

Invar® 36

UNS K93600 | W.Nr. 1.3912 | Nilo 36

Invar 36 is a 36% nickel-iron alloy notable for its uniquely low coefficient of thermal expansion which is roughly one-tenth that of carbon steel. It maintains nearly constant dimensions across the range of normal atmospheric temperatures up to 400°F (200°C).

  • Formas comuns: Plate, Round Bar, Sheet, Wire, Forgings.
  • Caraterística principal: Near-Zero Thermal Expansion at Room Temp.
  • Cryogenic: High toughness at cryogenic temperatures (-400°F).
  • CTE: 0.8 - 0.9 µin/in·°F (Typical 200°F to 400°F).
Why Choose Invar 36?

Invar 36 is indispensable for applications where dimensional changes due to temperature fluctuation must be minimized. From precision laser equipment to aerospace composite molds, Invar 36 ensures that the part shape remains consistent, preventing misalignment, warping, or stress buildup.

Dimensional Stability

The defining characteristic: prevents thermal distortion in sensitive instruments like optical measuring devices and laser benches.

Composite Tooling Match

Its CTE closely matches that of carbon-fiber composites, making it the premier material for aerospace lay-up molds.

Cryogenic Performance

Unlike many steels which become brittle, Invar 36 retains superior toughness and ductility at cryogenic temperatures (LNG/Liquid Oxygen).

Composição química (%)
Elemento Conteúdo (%)
Níquel (Ni) 35.0 - 37.0
Ferro (Fe) Equilíbrio
Carbono (C) 0,05 max
Manganês (Mn) 0.60 max
Silício (Si) 0.40 max

*Note: The precise 36% Nickel balance is critical for the "Invar Effect".

Especificações padrão
Forma do produto Normas (ASTM / AMS)
Placa, chapa, tira ASTM F1684, ASTM B753, AMS I-23011 (Class 7)
Bar, Rod, Forging ASTM F1684, AMS I-23011 (Class 7)
Ferramentas aeroespaciais Boeing BMS 7-320 (Invar 36 Tooling Plate)
Coeficiente médio de expansão térmica (CTE)
Gama de temperaturas CTE (µm/m-°C) CTE (µin/in·°F)
30 - 100°C 1.3 0.7
30 - 200°C 2.7 1.5
30 - 300°C 5.3 2.9

*Note: Above the Curie point (approx 280°C), expansion rates increase to match standard steels.

Aplicações típicas

Composite Tooling

Molds and dies for curing carbon fiber aerospace parts (Boeing 787 wings, fuselages).

LNG Piping

Transfer piping for Liquefied Natural Gas, preventing shrinkage and leakage at -162°C.

Optical Instruments

Laser housings, telescope supports, and seismic creep gauges requiring zero movement.

Thermostats

The low-expansion side of bimetallic strips used in thermal switches.

Need Invar 36 Tooling Plate or Rod?

We maintain a large stock of Invar 36 plate for immediate shipment. We offer saw cutting services to your exact dimensions.

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