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Steel A372 Grade D-N vs A372 Grade D-QT

Steel · A372 Grade D temper comparison

A372 Grade D-N and A372 Grade D-QT are two conditions of the same steel grade, A372 Grade D: N (normalized) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A372 Grade D-QT is the stronger of the two: yield strength 550 MPa (79.8 ksi) against 350 MPa (50.8 ksi) for A372 Grade D-N, about 57% more; tensile strength follows at 725 MPa (105 ksi) vs 640 MPa (92.8 ksi). In exchange, A372 Grade D-N is the more ductile: elongation 20% versus 18% for A372 Grade D-QT, and A372 Grade D-QT is harder (215 HB vs 190 HB). On the shop floor, A372 Grade D-N welds better (50 vs 40 out of 100).

A372 Grade D-NChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

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

A372 Grade D-N vs A372 Grade D-QT: properties

A372 Grade D-NA372 Grade D-QT

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

640 MPa92.8 ksi
725 MPa105 ksi

Yield Strength (0.2% offset)

350 MPa50.8 ksi
550 MPa79.8 ksi

Elongation at Break

20%
18%

Compressive Strength

350 MPa50.8 ksi
550 MPa79.8 ksi

Shear Strength

385 MPa55.8 ksi
435 MPa63.1 ksi

Fatigue Strength (Endurance Limit)

290 MPa42.1 ksi
325 MPa47.1 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
85 MPa·√m77.4 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

190 HB
215 HB

Hardness, Rockwell B

91 HRB
96 HRB

Hardness, Rockwell C

11 HRC
20 HRC

Hardness, Vickers

200 HV
225 HV

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 45%

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.

Thermal Conductivity

49 W/m·K28.3 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -29°C-20 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

9.8 % IACS
9.5 % IACS

Electrical Resistivity

1.76×10⁻⁷ Ω·m6.93 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) -0.65 V · Corrosion Resistance 12 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
55%

Weldability

50 / 100
40 / 100

Formability (cold)

35 / 100
25 / 100

Same in both: Castability 40 / 100 · Brazeability / Solderability 55 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 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 D

A372 Grade D-N vs A372 Grade D-QT — frequently asked

Is A372 Grade D-QT stronger than A372 Grade D-N?

Yes. A372 Grade D-QT has a typical yield strength of 550 MPa (79.8 ksi) against 350 MPa (50.8 ksi) for A372 Grade D-N — about 57% more. Tensile strength is 725 MPa (105 ksi) vs 640 MPa (92.8 ksi).

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

QT is the default A372 Grade D condition in the FabDigit quote flow. 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 D-N or A372 Grade D-QT?

A372 Grade D-N. Its machinability rates good (55/100) against fair (50/100) for A372 Grade D-QT; for welding the order is A372 Grade D-N first (fair, 50/100) then A372 Grade D-QT (fair, 40/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A372 Grade D-N and A372 Grade D-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.