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Steel A372 Grade K-N vs A372 Grade K QT-22HRC

Steel · A372 Grade K temper comparison

A372 Grade K-N and A372 Grade K QT-22HRC are two conditions of the same steel grade, A372 Grade K: N (normalized) versus QT-22HRC (Q&T, hardness-limited ≤22 HRC). The chemistry is identical, so every difference below comes from the condition. A372 Grade K QT-22HRC is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 470 MPa (68.2 ksi) for A372 Grade K-N, about 32% more.

A372 Grade K QT-22HRCChoose it when strength drives the design.

A372 Grade K-N vs A372 Grade K QT-22HRC: properties

A372 Grade K-NA372 Grade K QT-22HRC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Yield Strength (0.2% offset)

470 MPa68.2 ksi
620 MPa89.9 ksi

Elongation at Break

19%
21%

Reduction in Area

45%
55%

Compressive Strength

480 MPa69.6 ksi
630 MPa91.4 ksi

Fatigue Strength (Endurance Limit)

340 MPa49.3 ksi
350 MPa50.8 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
115 MPa·√m105 ksi·√in

Charpy V-Notch Impact (RT)

28 J20.7 ft·lbf
60 J44.3 ft·lbf

Hardness, Brinell

230 HB
225 HB

Hardness, Rockwell C

20 HRC
21 HRC

Hardness, Vickers

242 HV
236 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 · Tensile Strength (Ultimate) 760 MPa110 ksi · Shear Strength 460 MPa66.7 ksi

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F

Thermal

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

Thermal Conductivity

44 W/m·K25.4 BTU/hr·ft·°F
43 W/m·K24.8 BTU/hr·ft·°F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 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 Resistivity

2.15×10⁻⁷ Ω·m8.46 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Same in both: Electrical Conductivity 8 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 13 / 100

Manufacturability

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

Machinability

51 / 100
53 / 100

Machinability Rating (AISI 1212 = 100 %)

58%
60%

Weldability

46 / 100
48 / 100

Same in both: Formability (cold) 32 / 100 · Brazeability / Solderability 50 / 100 · Polishability 62 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 1.9 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%

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 K

A372 Grade K-N vs A372 Grade K QT-22HRC — frequently asked

Is A372 Grade K QT-22HRC stronger than A372 Grade K-N?

Yes. A372 Grade K QT-22HRC has a typical yield strength of 620 MPa (89.9 ksi) against 470 MPa (68.2 ksi) for A372 Grade K-N — about 32% more. Tensile strength is 760 MPa (110 ksi) vs 760 MPa (110 ksi).

Which condition does FabDigit quote by default, N or QT-22HRC?

QT is the default A372 Grade K condition in the FabDigit quote flow (neither N nor QT-22HRC). 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.

When should I choose A372 Grade K-N over A372 Grade K QT-22HRC?

Pick A372 Grade K QT-22HRC when strength drives the design.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A372 Grade K-N and A372 Grade K QT-22HRC 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.