Steel 45SCD6-A vs 45SCD6-HR
Steel · 45SCD6 temper comparison
45SCD6-A and 45SCD6-HR are two conditions of the same steel grade, 45SCD6: A (solution annealed) versus HR (hot rolled). The chemistry is identical, so every difference below comes from the condition. 45SCD6-HR is the stronger of the two: yield strength 640 MPa (92.8 ksi) against 460 MPa (66.7 ksi) for 45SCD6-A, about 39% more; tensile strength follows at 1,020 MPa (148 ksi) vs 780 MPa (113 ksi). In exchange, 45SCD6-A is the more ductile: elongation 18% versus 12% for 45SCD6-HR, and 45SCD6-HR is harder (295 HB vs 225 HB). 45SCD6-HR conducts heat better (42 W/m·K vs 36 W/m·K). On the shop floor, 45SCD6-A machines more easily (52 vs 38 out of 100).
45SCD6-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
45SCD6-HRChoose it when strength drives the design.
45SCD6-A vs 45SCD6-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.
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 C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 206 GPa29.9 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.8 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 100
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 30 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 30%
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.
45SCD6-A vs 45SCD6-HR — frequently asked
Is 45SCD6-HR stronger than 45SCD6-A?
Yes. 45SCD6-HR has a typical yield strength of 640 MPa (92.8 ksi) against 460 MPa (66.7 ksi) for 45SCD6-A — about 39% more. Tensile strength is 1,020 MPa (148 ksi) vs 780 MPa (113 ksi).
Which condition does FabDigit quote by default, A or HR?
QT-1800 is the default 45SCD6 condition in the FabDigit quote flow (neither A 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, 45SCD6-A or 45SCD6-HR?
45SCD6-A, by a small margin. Both rate fair for machinability — 52/100 against 38/100 for 45SCD6-HR; for welding the order is 45SCD6-A first (poor, 30/100) then 45SCD6-HR (poor, 22/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 45SCD6-A and 45SCD6-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.