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Steel A3 vs SKD1

Steel · grade comparison

Steel A3 and SKD1 are both steel grades. SKD1 is the stronger of the two: yield strength 460 MPa (66.7 ksi) against 430 MPa (62.4 ksi) for A3, about 7% more. In exchange, A3 is the more ductile: elongation 20% versus 12% for SKD1, and SKD1 is harder (235 HB vs 217 HB). A3 conducts heat better (24 W/m·K vs 20 W/m·K). On the shop floor, A3 machines more easily (fair vs poor) and SKD1 sits in a lower cost tier (standard, $$) than A3 (premium, $$$).

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

SKD1Choose it when strength drives the design, or when cost is the deciding factor.

A3 vs SKD1: properties

A3SKD1

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
780 MPa113 ksi

Yield Strength (0.2% offset)

430 MPa62.4 ksi
460 MPa66.7 ksi

Elongation at Break

20%
12%

Reduction in Area

35%
20%

Compressive Strength

900 MPa131 ksi
1,500 MPa218 ksi

Shear Strength

460 MPa66.7 ksi
480 MPa69.6 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
14 J10.3 ft·lbf

Hardness, Brinell

217 HB
235 HB

Hardness, Rockwell B

96 HRB
—

Hardness, Rockwell C

19 HRC
22 HRC

Hardness, Vickers

228 HV
245 HV

Fatigue Strength (Endurance Limit)

—
350 MPa50.8 ksi

Fracture Toughness (K_IC)

—
16 MPa·√m14.6 ksi·√in

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

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
1,270°C2,318 °F

Liquidus Temperature

1,470°C2,678 °F
1,400°C2,552 °F

Thermal

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

Thermal Conductivity

24 W/m·K13.9 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
10.8 µm/m·K6 µin/in·°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 · 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).

Galvanic Potential (seawater, vs SCE)

-0.6 V
-0.4 V

Corrosion Resistance

16 / 100
25 / 100

Manufacturability

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

Machinability

38 / 100
28 / 100

Machinability Rating (AISI 1212 = 100 %)

42%
27%

Formability (cold)

20 / 100
10 / 100

Polishability

70 / 100
60 / 100

Same in both: Weldability 15 / 100 · Castability 25 / 100 · Brazeability / Solderability 35 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

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

Typical Recycled Content

30%
40%

Same in both: Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

97 kN·m/kg
101 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
27.3 MN·m/kg

Modulus of Resilience

455 kJ/m³
504 kJ/m³

Thermal Diffusivity

6.6 mm²/s
5.6 mm²/s

Thermal Shock Resistance Index

8
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 scaleA3SKD1

Manufacturing and finishing

CapabilityA3SKD1
CNC machiningYes—
Default condition——
Relative cost$$$ Premium$$ Standard
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

A3 vs SKD1 — frequently asked

Is SKD1 stronger than A3?

Yes. SKD1 has a typical yield strength of 460 MPa (66.7 ksi) against 430 MPa (62.4 ksi) for A3 — about 7% more. Tensile strength is 780 MPa (113 ksi) vs 760 MPa (110 ksi).

Which is cheaper, A3 or SKD1?

SKD1 is the lower-cost material: it sits in the standard tier ($$) while A3 is premium ($$$). 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, A3 or SKD1?

A3. Its machinability rates fair (38/100) against poor (28/100) for SKD1.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A3 and SKD1 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.