Stainless Steel 302B-1/4 Hard vs 302B-3/4 Hard
Stainless Steel · 302B temper comparison
302B-1/4 Hard and 302B-3/4 Hard are two conditions of the same stainless steel grade, 302B: 1/4 Hard (quarter hard) versus 3/4 Hard (three-quarter hard). The chemistry is identical, so every difference below comes from the condition. 302B-3/4 Hard is the stronger of the two: yield strength 965 MPa (140 ksi) against 550 MPa (79.8 ksi) for 302B-1/4 Hard, about 75% more; tensile strength follows at 1,240 MPa (180 ksi) vs 895 MPa (130 ksi). In exchange, 302B-1/4 Hard is the more ductile: elongation 25% versus 10% for 302B-3/4 Hard, and 302B-3/4 Hard is harder (345 HB vs 250 HB). On the shop floor, 302B-1/4 Hard welds better (50 vs 40 out of 100).
302B-1/4 HardChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
302B-3/4 HardChoose it when strength drives the design.
302B-1/4 Hard vs 302B-3/4 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
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 160 GPa23.2 Msi · Poisson's Ratio 0.28
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,420°C2,588 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 15.9 W/m·K9.2 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 270 J/g116 BTU/lb · Max Service Temperature (continuous) 425°C797 °F · 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) -0.05 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 45 / 100 · Brazeability / Solderability 55 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 53 MJ/kg22,786 BTU/lb · Embodied Carbon (primary production) 5 kg CO₂/kg · Embodied Water 120 L/kg14.4 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.
302B-1/4 Hard vs 302B-3/4 Hard — frequently asked
Is 302B-3/4 Hard stronger than 302B-1/4 Hard?
Yes. 302B-3/4 Hard has a typical yield strength of 965 MPa (140 ksi) against 550 MPa (79.8 ksi) for 302B-1/4 Hard — about 75% more. Tensile strength is 1,240 MPa (180 ksi) vs 895 MPa (130 ksi).
Which condition does FabDigit quote by default, 1/4 Hard or 3/4 Hard?
Annealed is the default 302B condition in the FabDigit quote flow (neither 1/4 Hard nor 3/4 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.
Which is easier to machine, 302B-1/4 Hard or 302B-3/4 Hard?
302B-1/4 Hard. Its machinability rates fair (36/100) against poor (28/100) for 302B-3/4 Hard; for welding the order is 302B-1/4 Hard first (fair, 50/100) then 302B-3/4 Hard (fair, 40/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 302B-1/4 Hard and 302B-3/4 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.