FabDigitFabDigit

Steel A356 Grade 6 N+T+PWHT vs A356 Grade 6 Q&T

Steel · A356 Grade 6 temper comparison

A356 Grade 6 N+T+PWHT and A356 Grade 6 Q&T are two conditions of the same steel grade, A356 Grade 6: N+T+PWHT versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A356 Grade 6 Q&T is the stronger of the two: yield strength 450 MPa (65.3 ksi) against 360 MPa (52.2 ksi) for A356 Grade 6 N+T+PWHT, about 25% more; tensile strength follows at 620 MPa (89.9 ksi) vs 530 MPa (76.9 ksi). In exchange, A356 Grade 6 N+T+PWHT is the more ductile: elongation 24% versus 20% for A356 Grade 6 Q&T, and A356 Grade 6 Q&T is harder (190 HB vs 156 HB). On the shop floor, A356 Grade 6 N+T+PWHT machines more easily (good vs fair).

A356 Grade 6 N+T+PWHTChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

A356 Grade 6 Q&TChoose it when strength drives the design.

A356 Grade 6 N+T+PWHT vs A356 Grade 6 Q&T: properties

A356 Grade 6 N+T+PWHTA356 Grade 6 Q&T

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

530 MPa76.9 ksi
620 MPa89.9 ksi

Yield Strength (0.2% offset)

360 MPa52.2 ksi
450 MPa65.3 ksi

Elongation at Break

24%
20%

Reduction in Area

52%
55%

Compressive Strength

360 MPa52.2 ksi
380 MPa55.1 ksi

Shear Strength

325 MPa47.1 ksi
340 MPa49.3 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 ksi
280 MPa40.6 ksi

Fracture Toughness (K_IC)

130 MPa·√m118 ksi·√in
120 MPa·√m109 ksi·√in

Charpy V-Notch Impact (RT)

65 J47.9 ft·lbf
75 J55.3 ft·lbf

Hardness, Brinell

156 HB
190 HB

Hardness, Rockwell B

82 HRB
91 HRB

Hardness, Vickers

164 HV
175 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

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,510°C2,750 °F

Thermal

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

Max Service Temperature (continuous)

550°C1,022 °F
540°C1,004 °F

Same in both: Thermal Conductivity 38 W/m·K22 BTU/hr·ft·°F · Specific Heat Capacity 465 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 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 18 / 100

Manufacturability

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

Machinability

58 / 100
48 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
58%

Weldability

58 / 100
55 / 100

Formability (cold)

22 / 100
20 / 100

Same in both: Castability 68 / 100 · Brazeability / Solderability 45 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 75%

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 scaleA356 Grade 6

A356 Grade 6 N+T+PWHT vs A356 Grade 6 Q&T — frequently asked

Is A356 Grade 6 Q&T stronger than A356 Grade 6 N+T+PWHT?

Yes. A356 Grade 6 Q&T has a typical yield strength of 450 MPa (65.3 ksi) against 360 MPa (52.2 ksi) for A356 Grade 6 N+T+PWHT — about 25% more. Tensile strength is 620 MPa (89.9 ksi) vs 530 MPa (76.9 ksi).

Which condition does FabDigit quote by default, N+T+PWHT or Q&T?

N+T is the default A356 Grade 6 condition in the FabDigit quote flow (neither N+T+PWHT nor Q&T). 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, A356 Grade 6 N+T+PWHT or A356 Grade 6 Q&T?

A356 Grade 6 N+T+PWHT. Its machinability rates good (58/100) against fair (48/100) for A356 Grade 6 Q&T.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A356 Grade 6 N+T+PWHT and A356 Grade 6 Q&T 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.