Stainless Steel 1.4859-AC vs 1.4859-ST
Stainless Steel · 1.4859 temper comparison
1.4859-AC and 1.4859-ST are two conditions of the same stainless steel grade, 1.4859: AC (spheroidize annealed) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 245 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (spheroidize annealed versus solution annealed). 1.4859-ST is the more ductile: elongation 28% versus 20% for 1.4859-AC, and 1.4859-AC is harder (160 HB vs 150 HB).
1.4859-STChoose it when the part is bent, formed or impact-loaded.
1.4859-AC vs 1.4859-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
Same in both: Elastic (Young's) Modulus 172 GPa24.9 Msi · Shear Modulus 66 GPa9.6 Msi · Bulk Modulus 140 GPa20.3 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.9 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,330°C2,426 °F · Liquidus Temperature 1,395°C2,543 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 13 W/m·K7.5 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 15 µm/m·K8.3 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 1,050°C1,922 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 1.7 % IACS · Electrical Resistivity 1×10⁻⁶ Ω·m39.4 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.08 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 72 / 100 · Castability 70 / 100 · Brazeability / Solderability 55 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 78 MJ/kg33,534 BTU/lb · Embodied Carbon (primary production) 5.8 kg CO₂/kg · Embodied Water 200 L/kg24 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.
1.4859-AC vs 1.4859-ST — frequently asked
What is the difference between 1.4859-AC and 1.4859-ST?
1.4859-AC and 1.4859-ST are two conditions of the same stainless steel grade, 1.4859: AC (spheroidize annealed) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 245 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (spheroidize annealed versus solution annealed).
Which condition does FabDigit quote by default, AC or ST?
ST is the default 1.4859 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 1.4859-AC over 1.4859-ST?
Pick 1.4859-ST when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1.4859-AC and 1.4859-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.