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Steel A356 Grade 8-A vs A356 Grade 8 Q+T

Steel · A356 Grade 8 temper comparison

A356 Grade 8-A and A356 Grade 8 Q+T are two conditions of the same steel grade, A356 Grade 8: A (solution annealed) versus Q+T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. A356 Grade 8 Q+T is the stronger of the two: yield strength 550 MPa (79.8 ksi) against 365 MPa (52.9 ksi) for A356 Grade 8-A, about 51% more; tensile strength follows at 725 MPa (105 ksi) vs 585 MPa (84.8 ksi). In exchange, A356 Grade 8-A is the more ductile: elongation 24% versus 18% for A356 Grade 8 Q+T, and A356 Grade 8 Q+T is harder (225 HB vs 160 HB). On the shop floor, A356 Grade 8-A machines more easily (good vs fair).

A356 Grade 8-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

A356 Grade 8 Q+TChoose it when strength drives the design.

A356 Grade 8-A vs A356 Grade 8 Q+T: properties

A356 Grade 8-AA356 Grade 8 Q+T

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

585 MPa84.8 ksi
725 MPa105 ksi

Yield Strength (0.2% offset)

365 MPa52.9 ksi
550 MPa79.8 ksi

Elongation at Break

24%
18%

Reduction in Area

52%
45%

Compressive Strength

365 MPa52.9 ksi
450 MPa65.3 ksi

Shear Strength

355 MPa51.5 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

255 MPa37 ksi
320 MPa46.4 ksi

Fracture Toughness (K_IC)

115 MPa·√m105 ksi·√in
95 MPa·√m86.5 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

160 HB
225 HB

Hardness, Rockwell B

84 HRB
93 HRB

Hardness, Rockwell C

15 HRC
21 HRC

Hardness, Vickers

168 HV
210 HV

Same in both: Elastic (Young's) Modulus 207 GPa30 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 7.78 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,500°C2,732 °F

Thermal

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

Thermal Conductivity

36 W/m·K20.8 BTU/hr·ft·°F
35 W/m·K20.2 BTU/hr·ft·°F

Same in both: Specific Heat Capacity 460 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 · Max Service Temperature (continuous) 620°C1,148 °F · Min Service Temperature -30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

3.9 % IACS
3.8 % IACS

Electrical Resistivity

4.4×10⁻⁷ Ω·m17.3 µΩ·in
4.5×10⁻⁷ Ω·m17.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Corrosion Resistance 30 / 100

Manufacturability

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

Machinability

55 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
42%

Weldability

50 / 100
45 / 100

Formability (cold)

20 / 100
10 / 100

Same in both: Castability 70 / 100 · Brazeability / Solderability 40 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 55 L/kg6.6 gal/lb · Typical Recycled Content 80%

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 8

A356 Grade 8-A vs A356 Grade 8 Q+T — frequently asked

Is A356 Grade 8 Q+T stronger than A356 Grade 8-A?

Yes. A356 Grade 8 Q+T has a typical yield strength of 550 MPa (79.8 ksi) against 365 MPa (52.9 ksi) for A356 Grade 8-A — about 51% more. Tensile strength is 725 MPa (105 ksi) vs 585 MPa (84.8 ksi).

Which condition does FabDigit quote by default, A or Q+T?

N+T is the default A356 Grade 8 condition in the FabDigit quote flow (neither A 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 8-A or A356 Grade 8 Q+T?

A356 Grade 8-A. Its machinability rates good (55/100) against fair (40/100) for A356 Grade 8 Q+T; for welding the order is A356 Grade 8-A first (fair, 50/100) then A356 Grade 8 Q+T (fair, 45/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A356 Grade 8-A and A356 Grade 8 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.