Stainless Steel 309Cb 1/4H vs 309Cb-CD
Stainless Steel · 309Cb temper comparison
309Cb 1/4H and 309Cb-CD are two conditions of the same stainless steel grade, 309Cb: 1/4H (quarter hard) versus CD (cold drawn). The chemistry is identical, so every difference below comes from the condition. 309Cb 1/4H is the stronger of the two: yield strength 515 MPa (74.7 ksi) against 480 MPa (69.6 ksi) for 309Cb-CD, about 7% more; tensile strength follows at 860 MPa (125 ksi) vs 720 MPa (104 ksi). In exchange, 309Cb-CD is the more ductile: elongation 30% versus 20% for 309Cb 1/4H, and 309Cb 1/4H is harder (250 HB vs 200 HB). 309Cb-CD runs hotter in service (870°C vs 750°C continuous).
309Cb 1/4HChoose it when strength drives the design.
309Cb-CDChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
309Cb 1/4H vs 309Cb-CD: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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 B
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.98 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 15.6 W/m·K9 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 14.9 µm/m·K8.3 µin/in·°F · Latent Heat of Fusion 285 J/g123 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 7.8×10⁻⁷ Ω·m30.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 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 60 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 60 MJ/kg25,795 BTU/lb · Embodied Carbon (primary production) 4.8 kg CO₂/kg · Embodied Water 200 L/kg24 gal/lb · Typical Recycled Content 60%
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
309Cb 1/4H vs 309Cb-CD — frequently asked
Is 309Cb 1/4H stronger than 309Cb-CD?
Yes. 309Cb 1/4H has a typical yield strength of 515 MPa (74.7 ksi) against 480 MPa (69.6 ksi) for 309Cb-CD — about 7% more. Tensile strength is 860 MPa (125 ksi) vs 720 MPa (104 ksi).
Which condition does FabDigit quote by default, 1/4H or CD?
Annealed is the default 309Cb condition in the FabDigit quote flow (neither 1/4H nor CD). 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, 309Cb 1/4H or 309Cb-CD?
309Cb-CD. Its machinability rates fair (42/100) against poor (34/100) for 309Cb 1/4H; for welding the order is 309Cb-CD first (very good, 78/100) then 309Cb 1/4H (very good, 72/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 309Cb 1/4H and 309Cb-CD 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.