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Steel A2 vs D3

Steel · grade comparison

Steel A2 and D3 are both steel grades, both tool steel. D3 is the stronger of the two: tensile strength 800 MPa (116 ksi) against 740 MPa (107 ksi) for A2, about 8% more. In exchange, A2 is the more ductile: elongation 22% versus 14% for D3. A2 runs hotter in service (425°C vs 200°C continuous) and A2 conducts heat better (26 W/m·K vs 20 W/m·K). On the shop floor, A2 machines more easily (fair vs poor).

A2Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

D3Choose it when strength drives the design.

A2 vs D3: properties

A2D3

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

203 GPa29.4 Msi
210 GPa30.5 Msi

Shear Modulus

78 GPa11.3 Msi
81 GPa11.7 Msi

Tensile Strength (Ultimate)

740 MPa107 ksi
800 MPa116 ksi

Yield Strength (0.2% offset)

470 MPa68.2 ksi
460 MPa66.7 ksi

Elongation at Break

22%
14%

Reduction in Area

45%
30%

Compressive Strength

500 MPa72.5 ksi
520 MPa75.4 ksi

Shear Strength

450 MPa65.3 ksi
500 MPa72.5 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
350 MPa50.8 ksi

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

217 HB
225 HB

Hardness, Rockwell B

96 HRB
98 HRB

Hardness, Vickers

230 HV
235 HV

Fracture Toughness (K_IC)

—
28 MPa·√m25.5 ksi·√in

Hardness, Rockwell C

—
20 HRC

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28

Physical

Density and transition temperatures.

Density

7.86 g/cm³0.28 lb/in³
7.7 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,420°C2,588 °F
1,230°C2,246 °F

Liquidus Temperature

1,465°C2,669 °F
1,400°C2,552 °F

Thermal

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

Thermal Conductivity

26 W/m·K15 BTU/hr·ft·°F
20 W/m·K11.6 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

10.7 µm/m·K5.9 µin/in·°F
11.5 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

425°C797 °F
200°C392 °F

Min Service Temperature

-30°C-22 °F
-40°C-40 °F

Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

2.7 % IACS
2.6 % IACS

Same in both: Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

20 / 100
22 / 100

Manufacturability

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

Machinability

45 / 100
25 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
30%

Weldability

20 / 100
15 / 100

Formability (cold)

35 / 100
12 / 100

Castability

20 / 100
—

Brazeability / Solderability

40 / 100
25 / 100

Same in both: Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

2.6 kg CO₂/kg
2.8 kg CO₂/kg

Embodied Water

65 L/kg7.8 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

35%
40%

Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

94 kN·m/kg
104 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
27.3 MN·m/kg

Modulus of Resilience

544 kJ/m³
504 kJ/m³

Thermal Diffusivity

7.2 mm²/s
5.6 mm²/s

Thermal Shock Resistance Index

9
7

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 scaleA2D3

Manufacturing and finishing

CapabilityA2D3
Default conditionAnnealedAnnealed
Relative cost$$$ Premium$$$ Premium
Min. machined wall0.8 mm0.8 mm
Best machined surfaceRa 1.6 µmRa 1.6 µm

Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.

A2 vs D3 — frequently asked

Is D3 stronger than A2?

Yes. D3 has a typical tensile strength of 800 MPa (116 ksi) against 740 MPa (107 ksi) for A2 — about 8% more.

Which is cheaper, A2 or D3?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, A2 or D3?

A2. Its machinability rates fair (45/100) against poor (25/100) for D3; for welding the order is A2 first (poor, 20/100) then D3 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A2 and D3 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.