Steel A387 Gr 91 Cl 2 N+T+SPWHT vs A387 Gr 91 Cl 2 Q+T
Steel · A387 Gr 91 Cl 2 temper comparison
A387 Gr 91 Cl 2 N+T+SPWHT and A387 Gr 91 Cl 2 Q+T are two conditions of the same steel grade, A387 Gr 91 Cl 2: N+T+SPWHT (N+T + simulated post-weld heat treatment) versus Q+T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A387 Gr 91 Cl 2 Q+T is the stronger of the two: yield strength 520 MPa (75.4 ksi) against 450 MPa (65.3 ksi) for A387 Gr 91 Cl 2 N+T+SPWHT, about 16% more; tensile strength follows at 690 MPa (100 ksi) vs 620 MPa (89.9 ksi). In exchange, A387 Gr 91 Cl 2 N+T+SPWHT is the more ductile: elongation 24% versus 21% for A387 Gr 91 Cl 2 Q+T, and A387 Gr 91 Cl 2 Q+T is harder (225 HB vs 197 HB).
A387 Gr 91 Cl 2 N+T+SPWHTChoose it when the part is bent, formed or impact-loaded.
A387 Gr 91 Cl 2 Q+TChoose it when strength drives the design.
A387 Gr 91 Cl 2 N+T+SPWHT vs A387 Gr 91 Cl 2 Q+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 N+T+SPWHTA387 Gr 91 Cl 2 Q+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.
Same in both: Thermal Conductivity 26 W/m·K15 BTU/hr·ft·°F · 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 · Max Service Temperature (continuous) 600°C1,112 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
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 %)
Formability (cold)
Same in both: Weldability 45 / 100 · 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 N+T+SPWHT vs A387 Gr 91 Cl 2 Q+T — frequently asked
Is A387 Gr 91 Cl 2 Q+T stronger than A387 Gr 91 Cl 2 N+T+SPWHT?
Yes. A387 Gr 91 Cl 2 Q+T has a typical yield strength of 520 MPa (75.4 ksi) against 450 MPa (65.3 ksi) for A387 Gr 91 Cl 2 N+T+SPWHT — about 16% more. Tensile strength is 690 MPa (100 ksi) vs 620 MPa (89.9 ksi).
Which condition does FabDigit quote by default, N+T+SPWHT or Q+T?
N+T is the default A387 Gr 91 Cl 2 condition in the FabDigit quote flow (neither N+T+SPWHT nor Q+T). 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 N+T+SPWHT or A387 Gr 91 Cl 2 Q+T?
A387 Gr 91 Cl 2 N+T+SPWHT, by a small margin. Both rate fair for machinability — 42/100 against 35/100 for A387 Gr 91 Cl 2 Q+T.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A387 Gr 91 Cl 2 N+T+SPWHT and A387 Gr 91 Cl 2 Q+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.