Steel Super Invar-CD vs Super Invar-HR
Steel · Super Invar temper comparison
Super Invar-CD and Super Invar-HR are two conditions of the same steel grade, Super Invar: CD (cold drawn) versus HR (hot rolled). The chemistry is identical, so every difference below comes from the condition. Super Invar-CD is the stronger of the two: yield strength 570 MPa (82.7 ksi) against 340 MPa (49.3 ksi) for Super Invar-HR, about 68% more; tensile strength follows at 680 MPa (98.6 ksi) vs 530 MPa (76.9 ksi). In exchange, Super Invar-HR is the more ductile: elongation 28% versus 12% for Super Invar-CD, and Super Invar-CD is harder (210 HB vs 165 HB). On the shop floor, Super Invar-HR welds better (very good vs good).
Super Invar-CDChoose it when strength drives the design.
Super Invar-HRChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
Super Invar-CD vs Super Invar-HR: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel 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 steel 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 57 GPa8.3 Msi · Bulk Modulus 110 GPa16 Msi · Poisson's Ratio 0.28
Physical
Density and transition temperatures.
Same in both: Density 8.15 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °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 · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 70 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 75 MJ/kg32,244 BTU/lb · Embodied Carbon (primary production) 5.5 kg CO₂/kg · Embodied Water 130 L/kg15.6 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Super Invar-CD vs Super Invar-HR — frequently asked
Is Super Invar-CD stronger than Super Invar-HR?
Yes. Super Invar-CD has a typical yield strength of 570 MPa (82.7 ksi) against 340 MPa (49.3 ksi) for Super Invar-HR — about 68% more. Tensile strength is 680 MPa (98.6 ksi) vs 530 MPa (76.9 ksi).
Which condition does FabDigit quote by default, CD or HR?
ANN is the default Super Invar condition in the FabDigit quote flow (neither CD nor HR). 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.
Which is easier to machine, Super Invar-CD or Super Invar-HR?
Super Invar-CD. Its machinability rates fair (35/100) against poor (30/100) for Super Invar-HR; for welding the order is Super Invar-HR first (very good, 70/100) then Super Invar-CD (good, 60/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Super Invar-CD and Super Invar-HR 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.