Steel A48 Class 40-ANN vs A48 Class 40-SR
Steel · A48 Class 40 temper comparison
A48 Class 40-ANN and A48 Class 40-SR are two conditions of the same steel grade, A48 Class 40: ANN (annealed) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. A48 Class 40-SR is the stronger of the two: yield strength 220 MPa (31.9 ksi) against 165 MPa (23.9 ksi) for A48 Class 40-ANN, about 33% more; tensile strength follows at 285 MPa (41.3 ksi) vs 230 MPa (33.4 ksi). In exchange, A48 Class 40-ANN is the more ductile: elongation 0.9% versus 0.6% for A48 Class 40-SR, and A48 Class 40-SR is harder (230 HB vs 165 HB). A48 Class 40-SR is stiffer (125 GPa vs 110 GPa). On the shop floor, A48 Class 40-ANN machines more easily (excellent vs good) and A48 Class 40-ANN welds better (fair vs poor).
A48 Class 40-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A48 Class 40-SRChoose it when strength drives the design.
A48 Class 40-ANN vs A48 Class 40-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.
A48 Class 40-ANNA48 Class 40-SR
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Shear Modulus 50 GPa7.3 Msi · Bulk Modulus 87 GPa12.6 Msi · Poisson's Ratio 0.26
Physical
Density and transition temperatures.
Same in both: Density 7.15 g/cm³0.26 lb/in³ · Melting Point (Solidus) 1,150°C2,102 °F · Liquidus Temperature 1,240°C2,264 °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 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 220 J/g94.6 BTU/lb · Min Service Temperature -30°C-22 °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) -0.61 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 95 / 100 · Brazeability / Solderability 45 / 100 · Polishability 35 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 18 MJ/kg7,739 BTU/lb · Embodied Carbon (primary production) 1.7 kg CO₂/kg · Embodied Water 50 L/kg6 gal/lb · Typical Recycled Content 90%
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.
A48 Class 40-ANN vs A48 Class 40-SR — frequently asked
Is A48 Class 40-SR stronger than A48 Class 40-ANN?
Yes. A48 Class 40-SR has a typical yield strength of 220 MPa (31.9 ksi) against 165 MPa (23.9 ksi) for A48 Class 40-ANN — about 33% more. Tensile strength is 285 MPa (41.3 ksi) vs 230 MPa (33.4 ksi).
Which condition does FabDigit quote by default, ANN or SR?
AC is the default A48 Class 40 condition in the FabDigit quote flow (neither ANN 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.
Which is easier to machine, A48 Class 40-ANN or A48 Class 40-SR?
A48 Class 40-ANN. Its machinability rates excellent (85/100) against good (68/100) for A48 Class 40-SR; for welding the order is A48 Class 40-ANN first (fair, 35/100) then A48 Class 40-SR (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A48 Class 40-ANN and A48 Class 40-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.