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Steel 1J85 vs 45 Permalloy

Steel · grade comparison

Steel 1J85 and 45 Permalloy are both steel grades. 1J85 is the stronger of the two: yield strength 250 MPa (36.3 ksi) against 210 MPa (30.5 ksi) for 45 Permalloy, about 19% more; tensile strength follows at 600 MPa (87 ksi) vs 520 MPa (75.4 ksi). 45 Permalloy is harder — 125 HB against 115 HB for 1J85 — which matters for wear surfaces and threads. 45 Permalloy is lighter (8.17 g/cm³ vs 8.75 g/cm³ for 1J85) and 1J85 is stiffer (200 GPa vs 152 GPa). On the shop floor, 45 Permalloy welds better (good vs fair).

1J85Choose it when strength drives the design.

45 PermalloyChoose it when surface hardness matters, or when weight is the constraint.

1J85 vs 45 Permalloy: properties

1J8545 Permalloy

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
152 GPa22 Msi

Shear Modulus

76 GPa11 Msi
59 GPa8.6 Msi

Bulk Modulus

175 GPa25.4 Msi
127 GPa18.4 Msi

Poisson's Ratio

0.31
0.3

Tensile Strength (Ultimate)

600 MPa87 ksi
520 MPa75.4 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
210 MPa30.5 ksi

Reduction in Area

60%
65%

Compressive Strength

250 MPa36.3 ksi
—

Shear Strength

400 MPa58 ksi
350 MPa50.8 ksi

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
230 MPa33.4 ksi

Hardness, Brinell

115 HB
125 HB

Hardness, Rockwell B

65 HRB
70 HRB

Hardness, Vickers

120 HV
130 HV

Same in both: Elongation at Break 40% · Charpy V-Notch Impact (RT) 120 J88.5 ft·lbf

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,400°C2,552 °F
1,425°C2,597 °F

Same in both: Liquidus Temperature 1,450°C2,642 °F

Thermal

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

Thermal Conductivity

19 W/m·K11 BTU/hr·ft·°F
13.5 W/m·K7.8 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
500 J/kg·K0.12 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 µin/in·°F
8.5 µm/m·K4.7 µin/in·°F

Latent Heat of Fusion

290 J/g125 BTU/lb
275 J/g118 BTU/lb

Max Service Temperature (continuous)

200°C392 °F
400°C752 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

3.1 % IACS
3.8 % IACS

Electrical Resistivity

5.5×10⁻⁷ Ω·m21.7 µΩ·in
4.5×10⁻⁷ Ω·m17.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.2 V
-0.35 V

Corrosion Resistance

55 / 100
32 / 100

Manufacturability

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

Machinability

30 / 100
35 / 100

Machinability Rating (AISI 1212 = 100 %)

25%
35%

Weldability

50 / 100
60 / 100

Formability (cold)

85 / 100
80 / 100

Brazeability / Solderability

60 / 100
65 / 100

Same in both: Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

160 MJ/kg68,788 BTU/lb
90 MJ/kg38,693 BTU/lb

Embodied Carbon (primary production)

11 kg CO₂/kg
7.5 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
300 L/kg35.9 gal/lb

Typical Recycled Content

25%
20%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

69 kN·m/kg
64 kN·m/kg

Specific Stiffness (E / density)

22.9 MN·m/kg
18.6 MN·m/kg

Modulus of Resilience

156 kJ/m³
145 kJ/m³

Thermal Diffusivity

4.7 mm²/s
3.3 mm²/s

Same in both: Thermal Shock Resistance Index 5

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 scale45 Permalloy1J85

Manufacturing and finishing

Capability1J8545 Permalloy
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 45 Permalloy — frequently asked

Is 1J85 stronger than 45 Permalloy?

Yes. 1J85 has a typical yield strength of 250 MPa (36.3 ksi) against 210 MPa (30.5 ksi) for 45 Permalloy — about 19% more. Tensile strength is 600 MPa (87 ksi) vs 520 MPa (75.4 ksi).

Which is cheaper, 1J85 or 45 Permalloy?

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 45 Permalloy?

45 Permalloy. Its machinability rates fair (35/100) against poor (30/100) for 1J85; for welding the order is 45 Permalloy first (good, 60/100) then 1J85 (fair, 50/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 1J85 and 45 Permalloy 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.