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Steel 4140 vs 6152

Steel · grade comparison

Steel 4140 and 6152 are both steel grades. 4140 is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 415 MPa (60.2 ksi) for 6152, about 16% more. 4140 is harder — 210 HB against 197 HB for 6152 — which matters for wear surfaces and threads. On the shop floor, 4140 machines more easily (good vs fair) and 4140 welds better (fair vs poor).

4140Choose it when strength drives the design, or when surface hardness matters.

4140 vs 6152: properties

41406152

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
207 GPa30 Msi

Tensile Strength (Ultimate)

690 MPa100 ksi
670 MPa97.2 ksi

Yield Strength (0.2% offset)

480 MPa69.6 ksi
415 MPa60.2 ksi

Elongation at Break

22%
23%

Reduction in Area

50%
48%

Compressive Strength

480 MPa69.6 ksi
—

Fatigue Strength (Endurance Limit)

345 MPa50 ksi
320 MPa46.4 ksi

Fracture Toughness (K_IC)

110 MPa·√m100 ksi·√in
—

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

210 HB
197 HB

Hardness, Rockwell B

94 HRB
92 HRB

Hardness, Vickers

220 HV
—

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Shear Strength 420 MPa60.9 ksi

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,416°C2,581 °F
1,420°C2,588 °F

Liquidus Temperature

1,483°C2,701 °F
1,490°C2,714 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

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

Thermal Conductivity

42.6 W/m·K24.6 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Specific Heat Capacity

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

Max Service Temperature (continuous)

425°C797 °F
400°C752 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
7.5 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.3×10⁻⁷ Ω·m9.06 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

12 / 100
13 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V

Manufacturability

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

Machinability

60 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

62%
55%

Weldability

40 / 100
25 / 100

Castability

—
30 / 100

Same in both: Formability (cold) 40 / 100 · Brazeability / Solderability 55 / 100 · Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

32 MJ/kg13,758 BTU/lb
26 MJ/kg11,178 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
2 kg CO₂/kg

Typical Recycled Content

30%
35%

Same in both: Embodied Water 55 L/kg6.6 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

88 kN·m/kg
85 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.4 MN·m/kg

Modulus of Resilience

562 kJ/m³
416 kJ/m³

Thermal Diffusivity

11.5 mm²/s
12.5 mm²/s

Same in both: Thermal Shock Resistance Index 12

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 scale41406152

Manufacturing and finishing

Capability41406152
Casting & forgingYes—
Default conditionHRAnnealed
Relative cost$$ Standard$$ Standard
Min. machined wall0.8 mm0.8 mm
Best machined surfaceRa 1.6 µmRa 1.6 µm

Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.

4140 vs 6152 — frequently asked

Is 4140 stronger than 6152?

Yes. 4140 has a typical yield strength of 480 MPa (69.6 ksi) against 415 MPa (60.2 ksi) for 6152 — about 16% more. Tensile strength is 690 MPa (100 ksi) vs 670 MPa (97.2 ksi).

Which is cheaper, 4140 or 6152?

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

Which is easier to machine, 4140 or 6152?

4140. Its machinability rates good (60/100) against fair (50/100) for 6152; for welding the order is 4140 first (fair, 40/100) then 6152 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4140 and 6152 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.