Steel A387 Gr 9-ANN vs A387 Gr 9 CL2-QT
Steel · A387 Gr 9 temper comparison
A387 Gr 9-ANN and A387 Gr 9 CL2-QT are two conditions of the same steel grade, A387 Gr 9: ANN (annealed) versus CL2-QT (class 2, quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A387 Gr 9 CL2-QT is the stronger of the two: yield strength 505 MPa (73.2 ksi) against 270 MPa (39.2 ksi) for A387 Gr 9-ANN, about 87% more; tensile strength follows at 680 MPa (98.6 ksi) vs 450 MPa (65.3 ksi). In exchange, A387 Gr 9-ANN is the more ductile: elongation 28% versus 21% for A387 Gr 9 CL2-QT, and A387 Gr 9 CL2-QT is harder (220 HB vs 150 HB). On the shop floor, A387 Gr 9-ANN machines more easily (good vs fair).
A387 Gr 9-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A387 Gr 9 CL2-QTChoose it when strength drives the design.
A387 Gr 9-ANN vs A387 Gr 9 CL2-QT: 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 211 GPa30.6 Msi · Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 470 MPa68.2 ksi · Shear Strength 385 MPa55.8 ksi · Fracture Toughness (K_IC) 110 MPa·√m100 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 7.78 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,505°C2,741 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 29 W/m·K16.8 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.2 µm/m·K6.2 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 600°C1,112 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · 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) -0.55 V · Corrosion Resistance 30 / 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 40 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%
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 9-ANN vs A387 Gr 9 CL2-QT — frequently asked
Is A387 Gr 9 CL2-QT stronger than A387 Gr 9-ANN?
Yes. A387 Gr 9 CL2-QT has a typical yield strength of 505 MPa (73.2 ksi) against 270 MPa (39.2 ksi) for A387 Gr 9-ANN — about 87% more. Tensile strength is 680 MPa (98.6 ksi) vs 450 MPa (65.3 ksi).
Which condition does FabDigit quote by default, ANN or CL2-QT?
CL2 is the default A387 Gr 9 condition in the FabDigit quote flow (neither ANN nor CL2-QT). 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 9-ANN or A387 Gr 9 CL2-QT?
A387 Gr 9-ANN. Its machinability rates good (60/100) against fair (42/100) for A387 Gr 9 CL2-QT; for welding the order is A387 Gr 9-ANN first (fair, 45/100) then A387 Gr 9 CL2-QT (fair, 38/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A387 Gr 9-ANN and A387 Gr 9 CL2-QT 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.