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Steel 1J85 vs Fe-Co 50 (unalloyed)

Steel · grade comparison

Steel 1J85 and Fe-Co 50 (unalloyed) are both steel grades. Fe-Co 50 (unalloyed) is the stronger of the two: yield strength 800 MPa (116 ksi) against 250 MPa (36.3 ksi) for 1J85, about 3.2 times as much; tensile strength follows at 900 MPa (131 ksi) vs 600 MPa (87 ksi). In exchange, 1J85 is the more ductile: elongation 40% versus 1.5% for Fe-Co 50 (unalloyed), and Fe-Co 50 (unalloyed) is harder (300 HB vs 115 HB). Fe-Co 50 (unalloyed) is lighter (8.2 g/cm³ vs 8.75 g/cm³ for 1J85) and Fe-Co 50 (unalloyed) runs hotter in service (400°C vs 200°C continuous). On the shop floor, 1J85 machines more easily (30 vs 20 out of 100) and 1J85 welds better (fair vs poor).

1J85Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

Fe-Co 50 (unalloyed)Choose it when strength drives the design, or when weight is the constraint.

1J85 vs Fe-Co 50 (unalloyed): properties

1J85Fe-Co 50 (unalloyed)

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
210 GPa30.5 Msi

Shear Modulus

76 GPa11 Msi
81 GPa11.7 Msi

Bulk Modulus

175 GPa25.4 Msi
168 GPa24.4 Msi

Poisson's Ratio

0.31
0.3

Tensile Strength (Ultimate)

600 MPa87 ksi
900 MPa131 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
800 MPa116 ksi

Elongation at Break

40%
1.5%

Reduction in Area

60%
3%

Compressive Strength

250 MPa36.3 ksi
850 MPa123 ksi

Shear Strength

400 MPa58 ksi
590 MPa85.6 ksi

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
350 MPa50.8 ksi

Charpy V-Notch Impact (RT)

120 J88.5 ft·lbf
3 J2.2 ft·lbf

Hardness, Brinell

115 HB
300 HB

Hardness, Rockwell B

65 HRB
—

Hardness, Vickers

120 HV
320 HV

Fracture Toughness (K_IC)

—
30 MPa·√m27.3 ksi·√in

Hardness, Rockwell C

—
32 HRC

Physical

Density and transition temperatures.

Density

8.75 g/cm³0.32 lb/in³
8.2 g/cm³0.3 lb/in³

Melting Point (Solidus)

1,400°C2,552 °F
1,470°C2,678 °F

Liquidus Temperature

1,450°C2,642 °F
1,500°C2,732 °F

Thermal

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

Thermal Conductivity

19 W/m·K11 BTU/hr·ft·°F
43 W/m·K24.8 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
420 J/kg·K0.1 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 µin/in·°F
9.5 µm/m·K5.3 µin/in·°F

Latent Heat of Fusion

290 J/g125 BTU/lb
260 J/g112 BTU/lb

Max Service Temperature (continuous)

200°C392 °F
400°C752 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

3.1 % IACS
23 % IACS

Electrical Resistivity

5.5×10⁻⁷ Ω·m21.7 µΩ·in
7.5×10⁻⁸ Ω·m2.95 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.2 V
-0.55 V

Corrosion Resistance

55 / 100
14 / 100

Manufacturability

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

Machinability

30 / 100
20 / 100

Machinability Rating (AISI 1212 = 100 %)

25%
18%

Weldability

50 / 100
20 / 100

Formability (cold)

85 / 100
10 / 100

Brazeability / Solderability

60 / 100
55 / 100

Polishability

70 / 100
60 / 100

Castability

—
30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

160 MJ/kg68,788 BTU/lb
110 MJ/kg47,292 BTU/lb

Embodied Carbon (primary production)

11 kg CO₂/kg
8.5 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
400 L/kg47.9 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

69 kN·m/kg
110 kN·m/kg

Specific Stiffness (E / density)

22.9 MN·m/kg
25.6 MN·m/kg

Modulus of Resilience

156 kJ/m³
1,524 kJ/m³

Thermal Diffusivity

4.7 mm²/s
12.5 mm²/s

Thermal Shock Resistance Index

5
19

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 scaleFe-Co 50 (unalloyed)1J85

Manufacturing and finishing

Capability1J85Fe-Co 50 (unalloyed)
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

1J85 vs Fe-Co 50 (unalloyed) — frequently asked

Is Fe-Co 50 (unalloyed) stronger than 1J85?

Yes. Fe-Co 50 (unalloyed) has a typical yield strength of 800 MPa (116 ksi) against 250 MPa (36.3 ksi) for 1J85 — about 3.2 times as much. Tensile strength is 900 MPa (131 ksi) vs 600 MPa (87 ksi).

Which is cheaper, 1J85 or Fe-Co 50 (unalloyed)?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, 1J85 or Fe-Co 50 (unalloyed)?

1J85, by a small margin. Both rate poor for machinability — 30/100 against 20/100 for Fe-Co 50 (unalloyed); for welding the order is 1J85 first (fair, 50/100) then Fe-Co 50 (unalloyed) (poor, 20/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 1J85 and Fe-Co 50 (unalloyed) 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.