Steel A48 Class 20-ANN vs A48 Class 20-SR
Steel · A48 Class 20 temper comparison
A48 Class 20-ANN and A48 Class 20-SR are two conditions of the same steel grade, A48 Class 20: ANN (annealed) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. A48 Class 20-SR is the stronger of the two: tensile strength 150 MPa (21.8 ksi) against 135 MPa (19.6 ksi) for A48 Class 20-ANN, about 11% more. In exchange, A48 Class 20-ANN is the more ductile: elongation 0.8% versus 0.5% for A48 Class 20-SR, and A48 Class 20-SR is harder (150 HB vs 125 HB).
A48 Class 20-ANNChoose it when the part is bent, formed or impact-loaded.
A48 Class 20-SRChoose it when strength drives the design.
A48 Class 20-ANN vs A48 Class 20-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 20-ANNA48 Class 20-SR
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 32 GPa4.6 Msi · Bulk Modulus 56 GPa8.1 Msi · Poisson's Ratio 0.26
Physical
Density and transition temperatures.
Same in both: Density 7.1 g/cm³0.26 lb/in³ · Melting Point (Solidus) 1,150°C2,102 °F · Liquidus Temperature 1,175°C2,147 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.4 µm/m·K6.3 µin/in·°F · Latent Heat of Fusion 220 J/g94.6 BTU/lb · Max Service Temperature (continuous) 350°C662 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 18 / 100
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 96 / 100 · Brazeability / Solderability 50 / 100 · Polishability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 17 MJ/kg7,309 BTU/lb · Embodied Carbon (primary production) 1.6 kg CO₂/kg · Embodied Water 40 L/kg4.8 gal/lb · Typical Recycled Content 85%
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 20-ANN vs A48 Class 20-SR — frequently asked
Is A48 Class 20-SR stronger than A48 Class 20-ANN?
Yes. A48 Class 20-SR has a typical tensile strength of 150 MPa (21.8 ksi) against 135 MPa (19.6 ksi) for A48 Class 20-ANN — about 11% more.
Which condition does FabDigit quote by default, ANN or SR?
F is the default A48 Class 20 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 welds better, A48 Class 20-ANN or A48 Class 20-SR?
A48 Class 20-ANN. Its weldability rates fair (35/100) against poor (30/100) for A48 Class 20-SR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A48 Class 20-ANN and A48 Class 20-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.