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Steel A3 vs L6

Steel · grade comparison

Steel A3 and L6 are both steel grades. Both yield at about 430 MPa — strength does not separate them. A3 is harder — 217 HB against 197 HB for L6 — which matters for wear surfaces and threads. L6 runs hotter in service (400°C vs 200°C continuous) and L6 conducts heat better (38 W/m·K vs 24 W/m·K). On the shop floor, L6 machines more easily (good vs fair) and L6 forms better (30 vs 20 out of 100).

A3Choose it when surface hardness matters.

L6Choose it when the part sees heat, or when the part is machined in volume.

A3 vs L6: properties

A3L6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

203 GPa29.4 Msi
207 GPa30 Msi

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

760 MPa110 ksi
730 MPa106 ksi

Yield Strength (0.2% offset)

430 MPa62.4 ksi
420 MPa60.9 ksi

Elongation at Break

20%
22%

Reduction in Area

35%
45%

Compressive Strength

900 MPa131 ksi
430 MPa62.4 ksi

Shear Strength

460 MPa66.7 ksi
440 MPa63.8 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

217 HB
197 HB

Hardness, Rockwell B

96 HRB
92 HRB

Hardness, Rockwell C

19 HRC
—

Hardness, Vickers

228 HV
207 HV

Fatigue Strength (Endurance Limit)

—
330 MPa47.9 ksi

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
7.87 g/cm³0.28 lb/in³

Liquidus Temperature

1,470°C2,678 °F
1,480°C2,696 °F

Same in both: Melting Point (Solidus) 1,420°C2,588 °F

Thermal

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

Thermal Conductivity

24 W/m·K13.9 BTU/hr·ft·°F
38 W/m·K22 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

Max Service Temperature (continuous)

200°C392 °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.

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).

Corrosion Resistance

16 / 100
11 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V

Manufacturability

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

Machinability

38 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

42%
60%

Weldability

15 / 100
20 / 100

Formability (cold)

20 / 100
30 / 100

Castability

25 / 100
30 / 100

Brazeability / Solderability

35 / 100
40 / 100

Polishability

70 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

36 MJ/kg15,477 BTU/lb
33 MJ/kg14,187 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
93 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
26.3 MN·m/kg

Modulus of Resilience

455 kJ/m³
426 kJ/m³

Thermal Diffusivity

6.6 mm²/s
10.5 mm²/s

Thermal Shock Resistance Index

8
11

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 scaleA3L6

Manufacturing and finishing

CapabilityA3L6
CNC machiningYes—
Default condition——
Relative cost$$$ Premium$$$ Premium
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 L6 — frequently asked

What is the difference between A3 and L6?

Steel A3 and L6 are both steel grades. Both yield at about 430 MPa — strength does not separate them. A3 is harder — 217 HB against 197 HB for L6 — which matters for wear surfaces and threads.

Which is cheaper, A3 or L6?

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 L6?

L6. Its machinability rates good (55/100) against fair (38/100) for A3; for welding the order is L6 first (poor, 20/100) then A3 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A3 and L6 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.