Steel Fe-3Si-AB vs Fe-3Si-SR
Steel · Fe-3Si temper comparison
Fe-3Si-AB and Fe-3Si-SR are two conditions of the same steel grade, Fe-3Si: AB (as built (as printed)) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. Fe-3Si-AB is the stronger of the two: yield strength 450 MPa (65.3 ksi) against 400 MPa (58 ksi) for Fe-3Si-SR, about 13% more; tensile strength follows at 550 MPa (79.8 ksi) vs 500 MPa (72.5 ksi). In exchange, Fe-3Si-SR is the more ductile: elongation 6% versus 3% for Fe-3Si-AB, and Fe-3Si-AB is harder (235 HB vs 208 HB). Fe-3Si-SR runs hotter in service (400°C vs 350°C continuous) and Fe-3Si-SR conducts heat better (24 W/m·K vs 21 W/m·K).
Fe-3Si-ABChoose it when strength drives the design.
Fe-3Si-SRChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Fe-3Si-AB vs Fe-3Si-SR: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all 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 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Same in both: Density 7.65 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,470°C2,678 °F · Liquidus Temperature 1,505°C2,741 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.8 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 255 J/g110 BTU/lb · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 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 50 / 100 · Brazeability / Solderability 60 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 35 MJ/kg15,047 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Fe-3Si-AB vs Fe-3Si-SR — frequently asked
Is Fe-3Si-AB stronger than Fe-3Si-SR?
Yes. Fe-3Si-AB has a typical yield strength of 450 MPa (65.3 ksi) against 400 MPa (58 ksi) for Fe-3Si-SR — about 13% more. Tensile strength is 550 MPa (79.8 ksi) vs 500 MPa (72.5 ksi).
Which condition does FabDigit quote by default, AB or SR?
AB is the default Fe-3Si 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.
Which is easier to machine, Fe-3Si-AB or Fe-3Si-SR?
Fe-3Si-SR, by a small margin. Both rate fair for machinability — 43/100 against 38/100 for Fe-3Si-AB.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Fe-3Si-AB and Fe-3Si-SR 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.