Stainless Steel 1.4308 A351-CF8 vs 1.4308-ST
Stainless Steel · 1.4308 temper comparison
1.4308 A351-CF8 and 1.4308-ST are two conditions of the same stainless steel grade, 1.4308: A351-CF8 versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. 1.4308-ST is the stronger of the two: yield strength 250 MPa (36.3 ksi) against 205 MPa (29.7 ksi) for 1.4308 A351-CF8, about 22% more; tensile strength follows at 520 MPa (75.4 ksi) vs 485 MPa (70.3 ksi). 1.4308-ST is the more ductile: elongation 50% versus 35% for 1.4308 A351-CF8, and 1.4308 A351-CF8 is harder (160 HB vs 140 HB). 1.4308-ST runs hotter in service (760°C vs 538°C continuous).
1.4308-STChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
1.4308 A351-CF8 vs 1.4308-ST: 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 195 GPa28.3 Msi · Shear Modulus 75 GPa10.9 Msi · Bulk Modulus 140 GPa20.3 Msi · Poisson's Ratio 0.29 · Fracture Toughness (K_IC) 150 MPa·√m137 ksi·√in
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 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 16.2 W/m·K9.4 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 17 µm/m·K9.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · 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 68 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Same in both: Machinability 40 / 100 · Machinability Rating (AISI 1212 = 100 %) 40% · Formability (cold) 30 / 100 · Castability 78 / 100 · Brazeability / Solderability 60 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 60 MJ/kg25,795 BTU/lb · Embodied Carbon (primary production) 5 kg CO₂/kg · Embodied Water 130 L/kg15.6 gal/lb · Typical Recycled Content 70%
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.
1.4308 A351-CF8 vs 1.4308-ST — frequently asked
Is 1.4308-ST stronger than 1.4308 A351-CF8?
Yes. 1.4308-ST has a typical yield strength of 250 MPa (36.3 ksi) against 205 MPa (29.7 ksi) for 1.4308 A351-CF8 — about 22% more. Tensile strength is 520 MPa (75.4 ksi) vs 485 MPa (70.3 ksi).
Which condition does FabDigit quote by default, A351-CF8 or ST?
ST is the default 1.4308 condition in the FabDigit quote flow. 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 1.4308 A351-CF8 over 1.4308-ST?
Pick 1.4308-ST when strength drives the design, or when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1.4308 A351-CF8 and 1.4308-ST 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.