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Steel A372 Grade A N+T vs A372 Grade A-QT

Steel · A372 Grade A temper comparison

A372 Grade A N+T and A372 Grade A-QT are two conditions of the same steel grade, A372 Grade A: N+T (normalized and tempered) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A372 Grade A-QT is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 295 MPa (42.8 ksi) for A372 Grade A N+T, about 42% more; tensile strength follows at 600 MPa (87 ksi) vs 510 MPa (74 ksi). In exchange, A372 Grade A N+T is the more ductile: elongation 28% versus 23% for A372 Grade A-QT, and A372 Grade A-QT is harder (185 HB vs 148 HB). On the shop floor, A372 Grade A N+T machines more easily (65 vs 55 out of 100).

A372 Grade A N+TChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

A372 Grade A-QTChoose it when strength drives the design.

A372 Grade A N+T vs A372 Grade A-QT: properties

A372 Grade A N+TA372 Grade A-QT

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

510 MPa74 ksi
600 MPa87 ksi

Yield Strength (0.2% offset)

295 MPa42.8 ksi
420 MPa60.9 ksi

Elongation at Break

28%
23%

Compressive Strength

295 MPa42.8 ksi
420 MPa60.9 ksi

Shear Strength

315 MPa45.7 ksi
372 MPa54 ksi

Fatigue Strength (Endurance Limit)

225 MPa32.6 ksi
270 MPa39.2 ksi

Fracture Toughness (K_IC)

90 MPa·√m81.9 ksi·√in
100 MPa·√m91 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
70 J51.6 ft·lbf

Hardness, Brinell

148 HB
185 HB

Hardness, Rockwell B

79 HRB
90 HRB

Hardness, Vickers

155 HV
195 HV

Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 55%

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 1,510°C2,750 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

51 W/m·K29.5 BTU/hr·ft·°F
48 W/m·K27.7 BTU/hr·ft·°F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 425°C797 °F · Min Service Temperature -29°C-20 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10 % IACS
9.5 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
1.8×10⁻⁷ Ω·m7.09 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

65 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
55%

Weldability

78 / 100
70 / 100

Formability (cold)

63 / 100
48 / 100

Same in both: Castability 50 / 100 · Brazeability / Solderability 65 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleA372 Grade A

A372 Grade A N+T vs A372 Grade A-QT — frequently asked

Is A372 Grade A-QT stronger than A372 Grade A N+T?

Yes. A372 Grade A-QT has a typical yield strength of 420 MPa (60.9 ksi) against 295 MPa (42.8 ksi) for A372 Grade A N+T — about 42% more. Tensile strength is 600 MPa (87 ksi) vs 510 MPa (74 ksi).

Which condition does FabDigit quote by default, N+T or QT?

N is the default A372 Grade A condition in the FabDigit quote flow (neither N+T nor 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, A372 Grade A N+T or A372 Grade A-QT?

A372 Grade A N+T, by a small margin. Both rate good for machinability — 65/100 against 55/100 for A372 Grade A-QT; for welding the order is A372 Grade A N+T first (very good, 78/100) then A372 Grade A-QT (very good, 70/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A372 Grade A N+T and A372 Grade A-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.