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Steel 4130 vs Fe-3Si

Steel · grade comparison

Steel 4130 and Fe-3Si are both steel grades. 4130 is the stronger of the two: tensile strength 700 MPa (102 ksi) against 550 MPa (79.8 ksi) for Fe-3Si, about 27% more. 4130 is the more ductile: elongation 22% versus 3% for Fe-3Si, and Fe-3Si is harder (235 HB vs 210 HB). 4130 runs hotter in service (400°C vs 350°C continuous) and 4130 conducts heat better (42.7 W/m·K vs 21 W/m·K). On the shop floor, 4130 machines more easily (good vs fair), 4130 welds better (good vs fair), and 4130 sits in a lower cost tier (standard, $$) than Fe-3Si (high, $$$$).

4130Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

4130 vs Fe-3Si: properties

4130Fe-3Si

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
200 GPa29 Msi

Shear Modulus

80 GPa11.6 Msi
78 GPa11.3 Msi

Bulk Modulus

160 GPa23.2 Msi
165 GPa23.9 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

700 MPa102 ksi
550 MPa79.8 ksi

Yield Strength (0.2% offset)

440 MPa63.8 ksi
450 MPa65.3 ksi

Elongation at Break

22%
3%

Reduction in Area

50%
5%

Compressive Strength

480 MPa69.6 ksi
900 MPa131 ksi

Shear Strength

440 MPa63.8 ksi
350 MPa50.8 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
220 MPa31.9 ksi

Fracture Toughness (K_IC)

110 MPa·√m100 ksi·√in
35 MPa·√m31.9 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
6 J4.4 ft·lbf

Hardness, Brinell

210 HB
235 HB

Hardness, Rockwell B

95 HRB
—

Hardness, Vickers

228 HV
250 HV

Hardness, Rockwell C

—
22 HRC

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,432°C2,610 °F
1,470°C2,678 °F

Liquidus Temperature

1,510°C2,750 °F
1,505°C2,741 °F

Thermal

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

Thermal Conductivity

42.7 W/m·K24.7 BTU/hr·ft·°F
21 W/m·K12.1 BTU/hr·ft·°F

Specific Heat Capacity

477 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.2 µm/m·K6.8 µin/in·°F
11.8 µm/m·K6.6 µin/in·°F

Latent Heat of Fusion

272 J/g117 BTU/lb
255 J/g110 BTU/lb

Max Service Temperature (continuous)

400°C752 °F
350°C662 °F

Same in both: Min Service Temperature -50°C-58 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.7 % IACS
3.6 % IACS

Electrical Resistivity

2.23×10⁻⁷ Ω·m8.78 µΩ·in
4.9×10⁻⁷ Ω·m19.3 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.6 V

Corrosion Resistance

14 / 100
15 / 100

Manufacturability

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

Machinability

55 / 100
38 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
45%

Weldability

65 / 100
50 / 100

Formability (cold)

45 / 100
30 / 100

Brazeability / Solderability

70 / 100
60 / 100

Castability

—
50 / 100

Same in both: Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
35 MJ/kg15,047 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

45 L/kg5.4 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

89 kN·m/kg
72 kN·m/kg

Modulus of Resilience

472 kJ/m³
506 kJ/m³

Thermal Diffusivity

11.4 mm²/s
5.8 mm²/s

Thermal Shock Resistance Index

12
5

Same in both: Specific Stiffness (E / density) 26.1 MN·m/kg

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 scale4130Fe-3Si

Manufacturing and finishing

Capability4130Fe-3Si
CNC machiningYes—
Sheet metalYes—
Default conditionHR—
Relative cost$$ Standard$$$$ High
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.

4130 vs Fe-3Si — frequently asked

Is 4130 stronger than Fe-3Si?

Yes. 4130 has a typical tensile strength of 700 MPa (102 ksi) against 550 MPa (79.8 ksi) for Fe-3Si — about 27% more.

Which is cheaper, 4130 or Fe-3Si?

4130 is the lower-cost material: it sits in the standard tier ($$) while Fe-3Si is high ($$$$). 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, 4130 or Fe-3Si?

4130. Its machinability rates good (55/100) against fair (38/100) for Fe-3Si; for welding the order is 4130 first (good, 65/100) then Fe-3Si (fair, 50/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4130 and Fe-3Si 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.