Steel A372 Grade M-A vs A372 Grade M QT-CL85
Steel · A372 Grade M temper comparison
A372 Grade M-A and A372 Grade M QT-CL85 are two conditions of the same steel grade, A372 Grade M: A (solution annealed) versus QT-CL85 (class 85). The chemistry is identical, so every difference below comes from the condition. A372 Grade M QT-CL85 is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 400 MPa (58 ksi) for A372 Grade M-A, about 55% more; tensile strength follows at 790 MPa (115 ksi) vs 660 MPa (95.7 ksi). In exchange, A372 Grade M-A is the more ductile: elongation 24% versus 18% for A372 Grade M QT-CL85, and A372 Grade M QT-CL85 is harder (235 HB vs 197 HB). On the shop floor, A372 Grade M-A machines more easily (good vs fair) and A372 Grade M-A welds better (fair vs poor).
A372 Grade M-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A372 Grade M QT-CL85Choose it when strength drives the design.
A372 Grade M-A vs A372 Grade M QT-CL85: 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 M-AA372 Grade M QT-CL85
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
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 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 725 MPa105 ksi
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 1,495°C2,723 °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 475 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 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.8 % 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) -0.61 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 45 / 100 · Polishability 60 / 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 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.
A372 Grade M-A vs A372 Grade M QT-CL85 — frequently asked
Is A372 Grade M QT-CL85 stronger than A372 Grade M-A?
Yes. A372 Grade M QT-CL85 has a typical yield strength of 620 MPa (89.9 ksi) against 400 MPa (58 ksi) for A372 Grade M-A — about 55% more. Tensile strength is 790 MPa (115 ksi) vs 660 MPa (95.7 ksi).
Which condition does FabDigit quote by default, A or QT-CL85?
QT-CL100 is the default A372 Grade M condition in the FabDigit quote flow (neither A nor QT-CL85). 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 M-A or A372 Grade M QT-CL85?
A372 Grade M-A. Its machinability rates good (58/100) against fair (48/100) for A372 Grade M QT-CL85; for welding the order is A372 Grade M-A first (fair, 45/100) then A372 Grade M QT-CL85 (poor, 34/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A372 Grade M-A and A372 Grade M QT-CL85 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.