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Steel L6 vs O1

Steel · grade comparison

Steel L6 and O1 are both steel grades. L6 is the stronger of the two: tensile strength 730 MPa (106 ksi) against 690 MPa (100 ksi) for O1, about 6% more. In exchange, O1 is the more ductile: elongation 25% versus 22% for L6. On the shop floor, L6 machines more easily (good vs fair) and L6 sits in a lower cost tier (premium, $$$) than O1 (high, $$$$).

L6Choose it when strength drives the design, or when the part is machined in volume.

O1Choose it when the part is bent, formed or impact-loaded.

L6 vs O1: properties

L6O1

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
205 GPa29.7 Msi

Shear Modulus

80 GPa11.6 Msi
79 GPa11.5 Msi

Tensile Strength (Ultimate)

730 MPa106 ksi
690 MPa100 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
400 MPa58 ksi

Elongation at Break

22%
25%

Compressive Strength

430 MPa62.4 ksi
420 MPa60.9 ksi

Shear Strength

440 MPa63.8 ksi
420 MPa60.9 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
320 MPa46.4 ksi

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

197 HB
200 HB

Hardness, Rockwell B

92 HRB
94 HRB

Hardness, Vickers

207 HV
210 HV

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 45%

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,420°C2,588 °F
1,400°C2,552 °F

Liquidus Temperature

1,480°C2,696 °F
1,460°C2,660 °F

Thermal

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

Thermal Conductivity

38 W/m·K22 BTU/hr·ft·°F
35 W/m·K20.2 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 µin/in·°F
11.9 µm/m·K6.6 µin/in·°F

Min Service Temperature

-50°C-58 °F
-30°C-22 °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) 400°C752 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

11 / 100
12 / 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

55 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
42%

Formability (cold)

30 / 100
35 / 100

Castability

30 / 100
—

Brazeability / Solderability

40 / 100
45 / 100

Polishability

65 / 100
80 / 100

Same in both: Weldability 20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

33 MJ/kg14,187 BTU/lb
32 MJ/kg13,758 BTU/lb

Embodied Water

60 L/kg7.2 gal/lb
55 L/kg6.6 gal/lb

Typical Recycled Content

30%
40%

Same in both: Embodied Carbon (primary production) 2.4 kg CO₂/kg

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

93 kN·m/kg
88 kN·m/kg

Specific Stiffness (E / density)

26.3 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

426 kJ/m³
390 kJ/m³

Thermal Diffusivity

10.5 mm²/s
9.7 mm²/s

Thermal Shock Resistance Index

11
10

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 scaleO1L6

Manufacturing and finishing

CapabilityL6O1
CNC machining—Yes
Default condition—Annealed
Relative cost$$$ Premium$$$$ High
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

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

L6 vs O1 — frequently asked

Is L6 stronger than O1?

Yes. L6 has a typical tensile strength of 730 MPa (106 ksi) against 690 MPa (100 ksi) for O1 — about 6% more.

Which is cheaper, L6 or O1?

L6 is the lower-cost material: it sits in the premium tier ($$$) while O1 is high ($$$$). 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, L6 or O1?

L6. Its machinability rates good (55/100) against fair (45/100) for O1.

Ready to make it?

Upload a CAD file and FabDigit prices the part in L6 and O1 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.