Stainless Steel 321-1/2 Hard vs 321-1/4 Hard
Stainless Steel · 321 temper comparison
321-1/2 Hard and 321-1/4 Hard are two conditions of the same stainless steel grade, 321: 1/2 Hard (half hard) versus 1/4 Hard (quarter hard). The chemistry is identical, so every difference below comes from the condition. 321-1/2 Hard is the stronger of the two: yield strength 760 MPa (110 ksi) against 600 MPa (87 ksi) for 321-1/4 Hard, about 27% more; tensile strength follows at 1,035 MPa (150 ksi) vs 900 MPa (131 ksi). In exchange, 321-1/4 Hard is the more ductile: elongation 12% versus 8% for 321-1/2 Hard, and 321-1/2 Hard is harder (310 HB vs 265 HB).
321-1/2 HardChoose it when strength drives the design.
321-1/4 HardChoose it when the part is bent, formed or impact-loaded.
321-1/2 Hard vs 321-1/4 Hard: 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)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 193 GPa28 Msi · Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 150 GPa21.8 Msi · Poisson's Ratio 0.29 · Fracture Toughness (K_IC) 200 MPa·√m182 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 7.9 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,398°C2,548 °F · Liquidus Temperature 1,427°C2,601 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 16.1 W/m·K9.3 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.6 µm/m·K9.2 µin/in·°F · Latent Heat of Fusion 285 J/g123 BTU/lb · Max Service Temperature (continuous) 300°C572 °F · Min Service Temperature -196°C-321 °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) -0.05 V · Corrosion Resistance 62 / 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: 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) 6 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.
321-1/2 Hard vs 321-1/4 Hard — frequently asked
Is 321-1/2 Hard stronger than 321-1/4 Hard?
Yes. 321-1/2 Hard has a typical yield strength of 760 MPa (110 ksi) against 600 MPa (87 ksi) for 321-1/4 Hard — about 27% more. Tensile strength is 1,035 MPa (150 ksi) vs 900 MPa (131 ksi).
Which condition does FabDigit quote by default, 1/2 Hard or 1/4 Hard?
Solution Annealed is the default 321 condition in the FabDigit quote flow (neither 1/2 Hard nor 1/4 Hard). 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.
When should I choose 321-1/2 Hard over 321-1/4 Hard?
Pick 321-1/2 Hard when strength drives the design. Pick 321-1/4 Hard when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 321-1/2 Hard and 321-1/4 Hard 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.