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Steel A2 vs SKD11

Steel · grade comparison

Steel A2 and SKD11 are both steel grades, both tool steel. SKD11 is the stronger of the two: yield strength 500 MPa (72.5 ksi) against 470 MPa (68.2 ksi) for A2, about 6% more; tensile strength follows at 820 MPa (119 ksi) vs 740 MPa (107 ksi). In exchange, A2 is the more ductile: elongation 22% versus 12% for SKD11. A2 runs hotter in service (425°C vs 250°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.

SKD11Choose it when strength drives the design.

A2 vs SKD11: properties

A2SKD11

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
820 MPa119 ksi

Yield Strength (0.2% offset)

470 MPa68.2 ksi
500 MPa72.5 ksi

Elongation at Break

22%
12%

Reduction in Area

45%
20%

Compressive Strength

500 MPa72.5 ksi
900 MPa131 ksi

Shear Strength

450 MPa65.3 ksi
550 MPa79.8 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
380 MPa55.1 ksi

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
20 J14.8 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)

—
30 MPa·√m27.3 ksi·√in

Hardness, Rockwell C

—
20 HRC

Same in both: Bulk Modulus 160 GPa23.2 Msi

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
1,250°C2,282 °F

Liquidus Temperature

1,465°C2,669 °F
1,420°C2,588 °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
10.9 µm/m·K6.1 µin/in·°F

Max Service Temperature (continuous)

425°C797 °F
250°C482 °F

Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -30°C-22 °F

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
25 / 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
32 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
30%

Formability (cold)

35 / 100
25 / 100

Castability

20 / 100
25 / 100

Polishability

70 / 100
80 / 100

Same in both: Weldability 20 / 100 · Brazeability / Solderability 40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Water

65 L/kg7.8 gal/lb
70 L/kg8.4 gal/lb

Typical Recycled Content

35%
40%

Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

94 kN·m/kg
106 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
27.3 MN·m/kg

Modulus of Resilience

544 kJ/m³
595 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 scaleA2SKD11

Manufacturing and finishing

CapabilityA2SKD11
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 SKD11 — frequently asked

Is SKD11 stronger than A2?

Yes. SKD11 has a typical yield strength of 500 MPa (72.5 ksi) against 470 MPa (68.2 ksi) for A2 — about 6% more. Tensile strength is 820 MPa (119 ksi) vs 740 MPa (107 ksi).

Which is cheaper, A2 or SKD11?

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 SKD11?

A2. Its machinability rates fair (45/100) against poor (32/100) for SKD11.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A2 and SKD11 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.