Stainless Steel S21640-CD vs S21640 CW-3/4H
Stainless Steel · S21640 temper comparison
S21640-CD and S21640 CW-3/4H are two conditions of the same stainless steel grade, S21640: CD (cold drawn) versus CW-3/4H (cold Worked, 3/4 Hard). The chemistry is identical, so every difference below comes from the condition. S21640 CW-3/4H is the stronger of the two: yield strength 965 MPa (140 ksi) against 620 MPa (89.9 ksi) for S21640-CD, about 56% more; tensile strength follows at 1,170 MPa (170 ksi) vs 860 MPa (125 ksi). In exchange, S21640-CD is the more ductile: elongation 25% versus 12% for S21640 CW-3/4H, and S21640 CW-3/4H is harder (330 HB vs 255 HB). S21640-CD runs hotter in service (815°C vs 400°C continuous). On the shop floor, S21640-CD welds better (very good vs good).
S21640-CDChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
S21640 CW-3/4HChoose it when strength drives the design.
S21640-CD vs S21640 CW-3/4H: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
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 7.86 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,370°C2,498 °F · Liquidus Temperature 1,425°C2,597 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 15 W/m·K8.7 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.2 µm/m·K9 µin/in·°F · Latent Heat of Fusion 285 J/g123 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 2 % IACS
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: Castability 40 / 100 · Brazeability / Solderability 55 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 56 MJ/kg24,076 BTU/lb · Embodied Carbon (primary production) 5.8 kg CO₂/kg · Embodied Water 130 L/kg15.6 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.
S21640-CD vs S21640 CW-3/4H — frequently asked
Is S21640 CW-3/4H stronger than S21640-CD?
Yes. S21640 CW-3/4H has a typical yield strength of 965 MPa (140 ksi) against 620 MPa (89.9 ksi) for S21640-CD — about 56% more. Tensile strength is 1,170 MPa (170 ksi) vs 860 MPa (125 ksi).
Which condition does FabDigit quote by default, CD or CW-3/4H?
ANN is the default S21640 condition in the FabDigit quote flow (neither CD nor CW-3/4H). 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, S21640-CD or S21640 CW-3/4H?
S21640-CD, by a small margin. Both rate poor for machinability — 25/100 against 18/100 for S21640 CW-3/4H; for welding the order is S21640-CD first (very good, 70/100) then S21640 CW-3/4H (good, 55/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in S21640-CD and S21640 CW-3/4H 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.