Steel 30CrMnSi-CD vs 30CrMnSi QT880-520
Steel · 30CrMnSi temper comparison
30CrMnSi-CD and 30CrMnSi QT880-520 are two conditions of the same steel grade, 30CrMnSi: CD (cold drawn) versus QT880-520 (Q&T). The chemistry is identical, so every difference below comes from the condition. 30CrMnSi QT880-520 is the stronger of the two: yield strength 900 MPa (131 ksi) against 750 MPa (109 ksi) for 30CrMnSi-CD, about 20% more; tensile strength follows at 1,120 MPa (162 ksi) vs 900 MPa (131 ksi). 30CrMnSi QT880-520 is harder — 340 HB against 270 HB for 30CrMnSi-CD — which matters for wear surfaces and threads. 30CrMnSi QT880-520 runs hotter in service (400°C vs 300°C continuous). On the shop floor, 30CrMnSi-CD machines more easily (52 vs 40 out of 100).
30CrMnSi-CDChoose it when the part is machined in volume.
30CrMnSi QT880-520Choose it when strength drives the design, or when surface hardness matters.
30CrMnSi-CD vs 30CrMnSi QT880-520: 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 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 1,490°C2,714 °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 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -70°C-94 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 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
Same in both: Formability (cold) 25 / 100 · Brazeability / Solderability 55 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.3 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.
30CrMnSi-CD vs 30CrMnSi QT880-520 — frequently asked
Is 30CrMnSi QT880-520 stronger than 30CrMnSi-CD?
Yes. 30CrMnSi QT880-520 has a typical yield strength of 900 MPa (131 ksi) against 750 MPa (109 ksi) for 30CrMnSi-CD — about 20% more. Tensile strength is 1,120 MPa (162 ksi) vs 900 MPa (131 ksi).
Which condition does FabDigit quote by default, CD or QT880-520?
QT880-520 is the default 30CrMnSi 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, 30CrMnSi-CD or 30CrMnSi QT880-520?
30CrMnSi-CD, by a small margin. Both rate fair for machinability — 52/100 against 40/100 for 30CrMnSi QT880-520.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 30CrMnSi-CD and 30CrMnSi QT880-520 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.