Stainless Steel S21904 3/4H vs S21904-CD
Stainless Steel · S21904 temper comparison
S21904 3/4H and S21904-CD are two conditions of the same stainless steel grade, S21904: 3/4H (three-quarter hard) versus CD (cold drawn). The chemistry is identical, so every difference below comes from the condition. S21904 3/4H is the stronger of the two: yield strength 1,035 MPa (150 ksi) against 690 MPa (100 ksi) for S21904-CD, about 50% more; tensile strength follows at 1,240 MPa (180 ksi) vs 900 MPa (131 ksi). In exchange, S21904-CD is the more ductile: elongation 25% versus 12% for S21904 3/4H, and S21904-CD is harder (285 HB vs 200 HB). On the shop floor, S21904-CD welds better (very good vs good).
S21904 3/4HChoose it when strength drives the design.
S21904-CDChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
S21904 3/4H vs S21904-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
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
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 · Compressive Strength 420 MPa60.9 ksi · Shear Strength 480 MPa69.6 ksi · Fracture Toughness (K_IC) 200 MPa·√m182 ksi·√in · Hardness, Rockwell B 95 HRB · Hardness, Vickers 210 HV
Physical
Density and transition temperatures.
Same in both: Density 7.83 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 14.5 W/m·K8.4 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 15.1 µm/m·K8.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -253°C-423 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.4 % IACS · Electrical Resistivity 7.2×10⁻⁷ Ω·m28.3 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V · Corrosion Resistance 56 / 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: Castability 35 / 100 · Brazeability / Solderability 55 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 57 MJ/kg24,506 BTU/lb · Embodied Carbon (primary production) 5.4 kg CO₂/kg · Embodied Water 190 L/kg22.8 gal/lb · Typical Recycled Content 55%
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.
S21904 3/4H vs S21904-CD — frequently asked
Is S21904 3/4H stronger than S21904-CD?
Yes. S21904 3/4H has a typical yield strength of 1,035 MPa (150 ksi) against 690 MPa (100 ksi) for S21904-CD — about 50% more. Tensile strength is 1,240 MPa (180 ksi) vs 900 MPa (131 ksi).
Which condition does FabDigit quote by default, 3/4H or CD?
Annealed is the default S21904 condition in the FabDigit quote flow (neither 3/4H 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, S21904 3/4H or S21904-CD?
S21904-CD. Its machinability rates fair (35/100) against poor (30/100) for S21904 3/4H; for welding the order is S21904-CD first (very good, 70/100) then S21904 3/4H (good, 55/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in S21904 3/4H and S21904-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.