Steel 9255-CD vs 9255-QT315
Steel · 9255 temper comparison
9255-CD and 9255-QT315 are two conditions of the same steel grade, 9255: CD (cold drawn) versus QT315 (oil quenched, tempered 315 °C). The chemistry is identical, so every difference below comes from the condition. 9255-QT315 is the stronger of the two: yield strength 1,730 MPa (251 ksi) against 760 MPa (110 ksi) for 9255-CD, about 128% more; tensile strength follows at 1,960 MPa (284 ksi) vs 900 MPa (131 ksi). In exchange, 9255-CD is the more ductile: elongation 10% versus 5% for 9255-QT315, and 9255-QT315 is harder (555 HB vs 262 HB). 9255-CD runs hotter in service (300°C vs 230°C continuous) and 9255-CD conducts heat better (46 W/m·K vs 41 W/m·K). On the shop floor, 9255-CD machines more easily (fair vs poor) and 9255-CD welds better (poor vs not recommended).
9255-CDChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
9255-QT315Choose it when strength drives the design.
9255-CD vs 9255-QT315: 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 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) 1,400°C2,552 °F · Liquidus Temperature 1,470°C2,678 °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) 11.8 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 250 J/g107 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).
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: Castability 30 / 100 · Brazeability / Solderability 30 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
9255-CD vs 9255-QT315 — frequently asked
Is 9255-QT315 stronger than 9255-CD?
Yes. 9255-QT315 has a typical yield strength of 1,730 MPa (251 ksi) against 760 MPa (110 ksi) for 9255-CD — about 128% more. Tensile strength is 1,960 MPa (284 ksi) vs 900 MPa (131 ksi).
Which condition does FabDigit quote by default, CD or QT315?
QT425 is the default 9255 condition in the FabDigit quote flow (neither CD nor QT315). 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, 9255-CD or 9255-QT315?
9255-CD. Its machinability rates fair (48/100) against poor (15/100) for 9255-QT315; for welding the order is 9255-CD first (poor, 22/100) then 9255-QT315 (not recommended, 6/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 9255-CD and 9255-QT315 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.