Steel A387 Gr 91 Cl 2-ANN vs A387 Gr 91 Cl 2 N+T
Steel · A387 Gr 91 Cl 2 temper comparison
A387 Gr 91 Cl 2-ANN and A387 Gr 91 Cl 2 N+T are two conditions of the same steel grade, A387 Gr 91 Cl 2: ANN (annealed) versus N+T (normalized and tempered). The chemistry is identical, so every difference below comes from the condition. A387 Gr 91 Cl 2 N+T is the stronger of the two: yield strength 490 MPa (71.1 ksi) against 340 MPa (49.3 ksi) for A387 Gr 91 Cl 2-ANN, about 44% more; tensile strength follows at 660 MPa (95.7 ksi) vs 560 MPa (81.2 ksi). In exchange, A387 Gr 91 Cl 2-ANN is the more ductile: elongation 27% versus 23% for A387 Gr 91 Cl 2 N+T, and A387 Gr 91 Cl 2 N+T is harder (210 HB vs 180 HB). A387 Gr 91 Cl 2 N+T runs hotter in service (600°C vs 550°C continuous). On the shop floor, A387 Gr 91 Cl 2-ANN machines more easily (48 vs 38 out of 100).
A387 Gr 91 Cl 2-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A387 Gr 91 Cl 2 N+TChoose it when strength drives the design, or when the part sees heat.
A387 Gr 91 Cl 2-ANN vs A387 Gr 91 Cl 2 N+T: 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.
A387 Gr 91 Cl 2-ANNA387 Gr 91 Cl 2 N+T
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 218 GPa31.6 Msi · Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Same in both: Density 7.77 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,500°C2,732 °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) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V · Corrosion Resistance 25 / 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: Brazeability / Solderability 30 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.5 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.
A387 Gr 91 Cl 2-ANN vs A387 Gr 91 Cl 2 N+T — frequently asked
Is A387 Gr 91 Cl 2 N+T stronger than A387 Gr 91 Cl 2-ANN?
Yes. A387 Gr 91 Cl 2 N+T has a typical yield strength of 490 MPa (71.1 ksi) against 340 MPa (49.3 ksi) for A387 Gr 91 Cl 2-ANN — about 44% more. Tensile strength is 660 MPa (95.7 ksi) vs 560 MPa (81.2 ksi).
Which condition does FabDigit quote by default, ANN or N+T?
N+T is the default A387 Gr 91 Cl 2 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, A387 Gr 91 Cl 2-ANN or A387 Gr 91 Cl 2 N+T?
A387 Gr 91 Cl 2-ANN, by a small margin. Both rate fair for machinability — 48/100 against 38/100 for A387 Gr 91 Cl 2 N+T.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A387 Gr 91 Cl 2-ANN and A387 Gr 91 Cl 2 N+T 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.