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Steel A2 vs D2

Steel · grade comparison

Steel A2 and D2 are both steel grades, both tool steel. Both yield at about 470 MPa — strength does not separate them. A2 is the more ductile: elongation 22% versus 15% for D2. A2 conducts heat better (26 W/m·K vs 20 W/m·K). On the shop floor, A2 machines more easily (fair vs poor) and A2 sits in a lower cost tier (premium, $$$) than D2 (specialty, $$$$$).

A2Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

A2 vs D2: properties

A2D2

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
80 GPa11.6 Msi

Poisson's Ratio

0.28
0.29

Tensile Strength (Ultimate)

740 MPa107 ksi
750 MPa109 ksi

Yield Strength (0.2% offset)

470 MPa68.2 ksi
450 MPa65.3 ksi

Elongation at Break

22%
15%

Reduction in Area

45%
30%

Compressive Strength

500 MPa72.5 ksi
900 MPa131 ksi

Shear Strength

450 MPa65.3 ksi
470 MPa68.2 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
340 MPa49.3 ksi

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

217 HB
220 HB

Hardness, Rockwell B

96 HRB
97 HRB

Same in both: Bulk Modulus 160 GPa23.2 Msi · Hardness, Vickers 230 HV

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
1,421°C2,590 °F

Liquidus Temperature

1,465°C2,669 °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
10.5 µm/m·K5.8 µin/in·°F

Max Service Temperature (continuous)

425°C797 °F
400°C752 °F

Min Service Temperature

-30°C-22 °F
-50°C-58 °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.

Same in both: Electrical Conductivity 2.7 % IACS · Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

20 / 100
28 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.35 V

Manufacturability

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

Machinability

45 / 100
30 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
30%

Weldability

20 / 100
15 / 100

Formability (cold)

35 / 100
15 / 100

Castability

20 / 100
25 / 100

Brazeability / Solderability

40 / 100
35 / 100

Polishability

70 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

2.6 kg CO₂/kg
3 kg CO₂/kg

Embodied Water

65 L/kg7.8 gal/lb
80 L/kg9.6 gal/lb

Typical Recycled Content

35%
45%

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
97 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
27.3 MN·m/kg

Modulus of Resilience

544 kJ/m³
482 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 scaleA2D2

Manufacturing and finishing

CapabilityA2D2
Default conditionAnnealedAnnealed
Relative cost$$$ Premium$$$$$ Specialty
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 D2 — frequently asked

What is the difference between A2 and D2?

Steel A2 and D2 are both steel grades, both tool steel. Both yield at about 470 MPa — strength does not separate them. A2 is the more ductile: elongation 22% versus 15% for D2.

Which is cheaper, A2 or D2?

A2 is the lower-cost material: it sits in the premium tier ($$$) while D2 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, A2 or D2?

A2. Its machinability rates fair (45/100) against poor (30/100) for D2; for welding the order is A2 first (poor, 20/100) then D2 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A2 and D2 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.