Stainless Steel 1.4740-AC vs 1.4740-SR
Stainless Steel · 1.4740 temper comparison
1.4740-AC and 1.4740-SR are two conditions of the same stainless steel grade, 1.4740: AC (spheroidize annealed) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. 1.4740-AC is the stronger of the two: yield strength 310 MPa (45 ksi) against 290 MPa (42.1 ksi) for 1.4740-SR, about 7% more; tensile strength follows at 550 MPa (79.8 ksi) vs 520 MPa (75.4 ksi). In exchange, 1.4740-SR is the more ductile: elongation 6% versus 4% for 1.4740-AC, and 1.4740-AC is harder (270 HB vs 255 HB).
1.4740-ACChoose it when strength drives the design.
1.4740-SRChoose it when the part is bent, formed or impact-loaded.
1.4740-AC vs 1.4740-SR: 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)
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 77 GPa11.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Hardness, Rockwell B 100 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.6 g/cm³0.27 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 22 W/m·K12.7 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 950°C1,742 °F · Min Service Temperature 0°C32 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.28 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 72 / 100 · Brazeability / Solderability 35 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 50 MJ/kg21,496 BTU/lb · Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 120 L/kg14.4 gal/lb · Typical Recycled Content 80%
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.
1.4740-AC vs 1.4740-SR — frequently asked
Is 1.4740-AC stronger than 1.4740-SR?
Yes. 1.4740-AC has a typical yield strength of 310 MPa (45 ksi) against 290 MPa (42.1 ksi) for 1.4740-SR — about 7% more. Tensile strength is 550 MPa (79.8 ksi) vs 520 MPa (75.4 ksi).
Which condition does FabDigit quote by default, AC or SR?
A is the default 1.4740 condition in the FabDigit quote flow (neither AC nor SR). 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 1.4740-AC over 1.4740-SR?
Pick 1.4740-AC when strength drives the design. Pick 1.4740-SR when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1.4740-AC and 1.4740-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.