Steel A372 Grade G-ANN vs A372 Grade G QT-CL55
Steel · A372 Grade G temper comparison
A372 Grade G-ANN and A372 Grade G QT-CL55 are two conditions of the same steel grade, A372 Grade G: ANN (annealed) versus QT-CL55 (class 55). The chemistry is identical, so every difference below comes from the condition. A372 Grade G QT-CL55 is the stronger of the two: yield strength 430 MPa (62.4 ksi) against 380 MPa (55.1 ksi) for A372 Grade G-ANN, about 13% more. A372 Grade G QT-CL55 is harder — 190 HB against 180 HB for A372 Grade G-ANN — which matters for wear surfaces and threads. On the shop floor, A372 Grade G-ANN forms better (fair vs poor).
A372 Grade G QT-CL55Choose it when strength drives the design, or when surface hardness matters.
A372 Grade G-ANN vs A372 Grade G QT-CL55: 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.
A372 Grade G-ANNA372 Grade G QT-CL55
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
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, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 55% · Hardness, Rockwell C 19 HRC
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 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 50 / 100 · Polishability 62 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.2 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
A372 Grade G-ANN vs A372 Grade G QT-CL55 — frequently asked
Is A372 Grade G QT-CL55 stronger than A372 Grade G-ANN?
Yes. A372 Grade G QT-CL55 has a typical yield strength of 430 MPa (62.4 ksi) against 380 MPa (55.1 ksi) for A372 Grade G-ANN — about 13% more. Tensile strength is 640 MPa (92.8 ksi) vs 620 MPa (89.9 ksi).
Which condition does FabDigit quote by default, ANN or QT-CL55?
QT-CL70 is the default A372 Grade G condition in the FabDigit quote flow (neither ANN nor QT-CL55). 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, A372 Grade G-ANN or A372 Grade G QT-CL55?
A372 Grade G-ANN, by a small margin. Both rate good for machinability — 60/100 against 55/100 for A372 Grade G QT-CL55.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A372 Grade G-ANN and A372 Grade G QT-CL55 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.