Nickel Alloy Invar 36-HR vs Invar 36-O
Nickel Alloy · Invar 36 temper comparison
Invar 36-HR and Invar 36-O are two conditions of the same nickel alloy grade, Invar 36: HR (hot rolled) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. Invar 36-HR is the stronger of the two: yield strength 300 MPa (43.5 ksi) against 280 MPa (40.6 ksi) for Invar 36-O, about 7% more. In exchange, Invar 36-O is the more ductile: elongation 40% versus 35% for Invar 36-HR, and Invar 36-HR is harder (150 HB vs 135 HB).
Invar 36-HRChoose it when strength drives the design.
Invar 36-OChoose it when the part is bent, formed or impact-loaded.
Invar 36-HR vs Invar 36-O: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all nickel alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all nickel alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 55 GPa8 Msi · Bulk Modulus 110 GPa16 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 8.1 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,427°C2,601 °F · Liquidus Temperature 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Same in both: Thermal Conductivity 10.5 W/m·K6.1 BTU/hr·ft·°F · Specific Heat Capacity 515 J/kg·K0.12 BTU/lb·°F · Latent Heat of Fusion 275 J/g118 BTU/lb · Max Service Temperature (continuous) 230°C446 °F · Min Service Temperature -269°C-452 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.1 % IACS · Electrical Resistivity 8.2×10⁻⁷ Ω·m32.3 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.35 V · Corrosion Resistance 32 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Formability (cold)
Same in both: Machinability 30 / 100 · Machinability Rating (AISI 1212 = 100 %) 25% · Weldability 70 / 100 · Castability 40 / 100 · Brazeability / Solderability 65 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 90 MJ/kg38,693 BTU/lb · Embodied Carbon (primary production) 6.5 kg CO₂/kg · Embodied Water 180 L/kg21.6 gal/lb · Typical Recycled Content 30%
Strength versus weight
Yield strength against density for every nickel alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Invar 36-HR vs Invar 36-O — frequently asked
Is Invar 36-HR stronger than Invar 36-O?
Yes. Invar 36-HR has a typical yield strength of 300 MPa (43.5 ksi) against 280 MPa (40.6 ksi) for Invar 36-O — about 7% more. Tensile strength is 500 MPa (72.5 ksi) vs 490 MPa (71.1 ksi).
Which condition does FabDigit quote by default, HR or O?
O is the default Invar 36 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
When should I choose Invar 36-HR over Invar 36-O?
Pick Invar 36-HR when strength drives the design. Pick Invar 36-O when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Invar 36-HR and Invar 36-O side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.