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Steel O1 vs O6

Steel · grade comparison

Steel O1 and O6 are both steel grades. Both yield at about 400 MPa — strength does not separate them. O1 is the more ductile: elongation 25% versus 22% for O6. O1 conducts electricity better (7 % IACS vs 3.4 % IACS). On the shop floor, O6 machines more easily (good vs fair) and O6 sits in a lower cost tier (premium, $$$) than O1 (high, $$$$).

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

O6Choose it when the part is machined in volume, or when cost is the deciding factor.

O1 vs O6: properties

O1O6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
203 GPa29.4 Msi

Tensile Strength (Ultimate)

690 MPa100 ksi
720 MPa104 ksi

Yield Strength (0.2% offset)

400 MPa58 ksi
415 MPa60.2 ksi

Elongation at Break

25%
22%

Reduction in Area

45%
40%

Compressive Strength

420 MPa60.9 ksi
430 MPa62.4 ksi

Shear Strength

420 MPa60.9 ksi
470 MPa68.2 ksi

Fatigue Strength (Endurance Limit)

320 MPa46.4 ksi
330 MPa47.9 ksi

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
40 J29.5 ft·lbf

Hardness, Rockwell B

94 HRB
93 HRB

Same in both: Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 200 HB · Hardness, Vickers 210 HV

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,400°C2,552 °F
1,290°C2,354 °F

Liquidus Temperature

1,460°C2,660 °F
1,420°C2,588 °F

Thermal

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

Thermal Conductivity

35 W/m·K20.2 BTU/hr·ft·°F
32 W/m·K18.5 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
12.2 µm/m·K6.8 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) 400°C752 °F · Min Service Temperature -30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7 % IACS
3.4 % IACS

Electrical Resistivity

2.5×10⁻⁷ Ω·m9.84 µΩ·in
5×10⁻⁷ Ω·m19.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

12 / 100
9 / 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

45 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

42%
65%

Formability (cold)

35 / 100
25 / 100

Brazeability / Solderability

45 / 100
40 / 100

Polishability

80 / 100
45 / 100

Castability

—
20 / 100

Same in both: Weldability 20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

32 MJ/kg13,758 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

2.4 kg CO₂/kg
2.5 kg CO₂/kg

Embodied Water

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

Same in both: Typical Recycled Content 40%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

88 kN·m/kg
94 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.4 MN·m/kg

Modulus of Resilience

390 kJ/m³
424 kJ/m³

Thermal Diffusivity

9.7 mm²/s
9 mm²/s

Thermal Shock Resistance Index

10
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 scaleO1O6

Manufacturing and finishing

CapabilityO1O6
CNC machiningYes—
Default conditionAnnealed—
Relative cost$$$$ High$$$ 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.

O1 vs O6 — frequently asked

What is the difference between O1 and O6?

Steel O1 and O6 are both steel grades. Both yield at about 400 MPa — strength does not separate them. O1 is the more ductile: elongation 25% versus 22% for O6.

Which is cheaper, O1 or O6?

O6 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, O1 or O6?

O6. Its machinability rates good (62/100) against fair (45/100) for O1.

Ready to make it?

Upload a CAD file and FabDigit prices the part in O1 and O6 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.