Steel 94B30-CD vs 94B30-QT540
Steel · 94B30 temper comparison
94B30-CD and 94B30-QT540 are two conditions of the same steel grade, 94B30: CD (cold drawn) versus QT540 (Q&T 540 °C). The chemistry is identical, so every difference below comes from the condition. 94B30-QT540 is the stronger of the two: yield strength 860 MPa (125 ksi) against 660 MPa (95.7 ksi) for 94B30-CD, about 30% more; tensile strength follows at 990 MPa (144 ksi) vs 760 MPa (110 ksi). 94B30-QT540 is the more ductile: elongation 17% versus 13% for 94B30-CD, and 94B30-QT540 is harder (293 HB vs 223 HB). 94B30-QT540 runs hotter in service (400°C vs 350°C continuous). On the shop floor, 94B30-CD machines more easily (good vs fair).
94B30-CDChoose it when the part is machined in volume.
94B30-QT540Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
94B30-CD vs 94B30-QT540: 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
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 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · 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) -0.61 V · Corrosion Resistance 10 / 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 55 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
94B30-CD vs 94B30-QT540 — frequently asked
Is 94B30-QT540 stronger than 94B30-CD?
Yes. 94B30-QT540 has a typical yield strength of 860 MPa (125 ksi) against 660 MPa (95.7 ksi) for 94B30-CD — about 30% more. Tensile strength is 990 MPa (144 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, CD or QT540?
QT540 is the default 94B30 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.
Which is easier to machine, 94B30-CD or 94B30-QT540?
94B30-CD. Its machinability rates good (60/100) against fair (45/100) for 94B30-QT540; for welding the order is 94B30-CD first (fair, 40/100) then 94B30-QT540 (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 94B30-CD and 94B30-QT540 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.