Nickel Alloy Invar 36 vs Kovar
Nickel Alloy · grade comparison
Nickel Alloy Invar 36 and Kovar are both nickel alloy grades, both low expansion ni. Kovar is the stronger of the two: yield strength 345 MPa (50 ksi) against 280 MPa (40.6 ksi) for Invar 36, about 23% more; tensile strength follows at 520 MPa (75.4 ksi) vs 490 MPa (71.1 ksi). In exchange, Invar 36 is the more ductile: elongation 40% versus 30% for Kovar, and Kovar is harder (145 HB vs 135 HB). Invar 36 is lighter (8.1 g/cm³ vs 8.36 g/cm³ for Kovar) and Kovar runs hotter in service (450°C vs 230°C continuous). On the shop floor, Kovar welds better (80 vs 70 out of 100).
Invar 36Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
KovarChoose it when strength drives the design, or when the part sees heat.
Invar 36 vs Kovar: 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
Shear Modulus
Bulk Modulus
Poisson's Ratio
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
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | Invar 36 | Kovar |
|---|---|---|
| Default condition | O | O |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | 1.5 mm | 1.5 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 5 finishes: Electropolishing, Gold Plating, HVOF Coating, Plasma Spray, Silver Plating.
Invar 36 vs Kovar — frequently asked
Is Kovar stronger than Invar 36?
Yes. Kovar has a typical yield strength of 345 MPa (50 ksi) against 280 MPa (40.6 ksi) for Invar 36 — about 23% more. Tensile strength is 520 MPa (75.4 ksi) vs 490 MPa (71.1 ksi).
Which is cheaper, Invar 36 or Kovar?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, Invar 36 or Kovar?
Kovar. Its weldability rates very good (80/100) against very good (70/100) for Invar 36.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Invar 36 and Kovar 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.