Stainless Steel S31655 1/4H vs S31655 3/4H
Stainless Steel · S31655 temper comparison
S31655 1/4H and S31655 3/4H are two conditions of the same stainless steel grade, S31655: 1/4H (quarter hard) versus 3/4H (three-quarter hard). The chemistry is identical, so every difference below comes from the condition. S31655 3/4H is the stronger of the two: yield strength 950 MPa (138 ksi) against 550 MPa (79.8 ksi) for S31655 1/4H, about 73% more; tensile strength follows at 1,160 MPa (168 ksi) vs 880 MPa (128 ksi). In exchange, S31655 1/4H is the more ductile: elongation 12% versus 6% for S31655 3/4H, and S31655 3/4H is harder (330 HB vs 250 HB). On the shop floor, S31655 1/4H welds better (very good vs good).
S31655 1/4HChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
S31655 3/4HChoose it when strength drives the design.
S31655 1/4H vs S31655 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.
Elastic (Young's) Modulus
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
Hardness, Vickers
Same in both: Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 166 GPa24.1 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Same in both: Density 7.98 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,375°C2,507 °F · Liquidus Temperature 1,400°C2,552 °F
Thermal
How each material carries heat and how hot it can run.
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) 16 µm/m·K8.9 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 7.9×10⁻⁷ Ω·m31.1 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: Brazeability / Solderability 60 / 100 · Polishability 78 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 57 MJ/kg24,506 BTU/lb · Embodied Carbon (primary production) 5.5 kg CO₂/kg · Embodied Water 220 L/kg26.4 gal/lb · Typical Recycled Content 65%
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.
S31655 1/4H vs S31655 3/4H — frequently asked
Is S31655 3/4H stronger than S31655 1/4H?
Yes. S31655 3/4H has a typical yield strength of 950 MPa (138 ksi) against 550 MPa (79.8 ksi) for S31655 1/4H — about 73% more. Tensile strength is 1,160 MPa (168 ksi) vs 880 MPa (128 ksi).
Which condition does FabDigit quote by default, 1/4H or 3/4H?
Annealed is the default S31655 condition in the FabDigit quote flow (neither 1/4H nor 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, S31655 1/4H or S31655 3/4H?
S31655 1/4H. Its machinability rates fair (36/100) against poor (27/100) for S31655 3/4H; for welding the order is S31655 1/4H first (very good, 75/100) then S31655 3/4H (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in S31655 1/4H and S31655 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.