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Steel A3 vs SKS3

Steel · grade comparison

Steel A3 and SKS3 are both steel grades, both tool steel. Both yield at about 430 MPa — strength does not separate them. A3 is the more ductile: elongation 20% versus 18% for SKS3, and A3 is harder (217 HB vs 200 HB). SKS3 conducts heat better (33 W/m·K vs 24 W/m·K). On the shop floor, SKS3 machines more easily (50 vs 38 out of 100).

A3Choose it when the part is bent, formed or impact-loaded.

SKS3Choose it when the part is machined in volume.

A3 vs SKS3: properties

A3SKS3

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

203 GPa29.4 Msi
210 GPa30.5 Msi

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

760 MPa110 ksi
750 MPa109 ksi

Yield Strength (0.2% offset)

430 MPa62.4 ksi
450 MPa65.3 ksi

Elongation at Break

20%
18%

Compressive Strength

900 MPa131 ksi
—

Shear Strength

460 MPa66.7 ksi
470 MPa68.2 ksi

Hardness, Brinell

217 HB
200 HB

Hardness, Rockwell B

96 HRB
94 HRB

Hardness, Rockwell C

19 HRC
—

Hardness, Vickers

228 HV
210 HV

Fatigue Strength (Endurance Limit)

—
340 MPa49.3 ksi

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 35% · Charpy V-Notch Impact (RT) 25 J18.4 ft·lbf

Physical

Density and transition temperatures.

Density

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

Same in both: Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,470°C2,678 °F

Thermal

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

Thermal Conductivity

24 W/m·K13.9 BTU/hr·ft·°F
33 W/m·K19.1 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

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

Min Service Temperature

-30°C-22 °F
-20°C-4 °F

Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 200°C392 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.7 % IACS
7 % IACS

Electrical Resistivity

6.5×10⁻⁷ Ω·m25.6 µΩ·in
2.5×10⁻⁷ Ω·m9.84 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
—

Corrosion Resistance

16 / 100
15 / 100

Manufacturability

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

Machinability

38 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

42%
45%

Weldability

15 / 100
12 / 100

Formability (cold)

20 / 100
25 / 100

Castability

25 / 100
—

Brazeability / Solderability

35 / 100
40 / 100

Polishability

70 / 100
80 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

36 MJ/kg15,477 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

2.6 kg CO₂/kg
2.4 kg CO₂/kg

Same in both: Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

97 kN·m/kg
96 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

455 kJ/m³
482 kJ/m³

Thermal Diffusivity

6.6 mm²/s
9.1 mm²/s

Thermal Shock Resistance Index

8
9

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 scaleA3SKS3

Manufacturing and finishing

CapabilityA3SKS3
Default condition—Annealed
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.

A3 vs SKS3 — frequently asked

What is the difference between A3 and SKS3?

Steel A3 and SKS3 are both steel grades, both tool steel. Both yield at about 430 MPa — strength does not separate them. A3 is the more ductile: elongation 20% versus 18% for SKS3, and A3 is harder (217 HB vs 200 HB).

Which is cheaper, A3 or SKS3?

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, A3 or SKS3?

SKS3, by a small margin. Both rate fair for machinability — 50/100 against 38/100 for A3.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A3 and SKS3 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.