FabDigit

4145 vs 4140 and 2 more: properties

4145414041505160

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

830 MPa120 ksi
690 MPa100 ksi
860 MPa125 ksi
725 MPa105 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
480 MPa69.6 ksi
520 MPa75.4 ksi
275 MPa39.9 ksi

Elongation at Break

18%
22%
16%
17%

Reduction in Area

45%
50%
40%
31%

Compressive Strength

540 MPa78.3 ksi
480 MPa69.6 ksi

Shear Strength

500 MPa72.5 ksi
420 MPa60.9 ksi
560 MPa81.2 ksi
450 MPa65.3 ksi

Fatigue Strength (Endurance Limit)

370 MPa53.7 ksi
345 MPa50 ksi
390 MPa56.6 ksi
330 MPa47.9 ksi

Fracture Toughness (K_IC)

95 MPa·√m86.5 ksi·√in
110 MPa·√m100 ksi·√in

Charpy V-Notch Impact (RT)

28 J20.7 ft·lbf
40 J29.5 ft·lbf
25 J18.4 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

235 HB
210 HB
235 HB
197 HB

Hardness, Rockwell B

99 HRB
94 HRB
92 HRB

Hardness, Rockwell C

22 HRC
21 HRC

Hardness, Vickers

247 HV
220 HV
245 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,416°C2,581 °F
1,416°C2,581 °F
1,416°C2,581 °F
1,425°C2,597 °F

Liquidus Temperature

1,480°C2,696 °F
1,483°C2,701 °F
1,490°C2,714 °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

43 W/m·K24.8 BTU/hr·ft·°F
42.6 W/m·K24.6 BTU/hr·ft·°F
42.6 W/m·K24.6 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Specific Heat Capacity

475 J/kg·K0.11 BTU/lb·°F
473 J/kg·K0.11 BTU/lb·°F
473 J/kg·K0.11 BTU/lb·°F
490 J/kg·K0.12 BTU/lb·°F

Max Service Temperature (continuous)

400°C752 °F
425°C797 °F
400°C752 °F
250°C482 °F

Min Service Temperature

-30°C-22 °F
-40°C-40 °F
-40°C-40 °F
-40°C-40 °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

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 7.8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
-0.61 V
-0.6 V
-0.61 V

Corrosion Resistance

13 / 100
12 / 100
12 / 100
10 / 100

Manufacturability

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

Machinability

50 / 100
60 / 100
45 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
62%
50%
56%

Weldability

35 / 100
40 / 100
25 / 100
25 / 100

Formability (cold)

25 / 100
40 / 100
25 / 100
45 / 100

Castability

40 / 100
35 / 100
40 / 100

Brazeability / Solderability

45 / 100
55 / 100
55 / 100
55 / 100

Polishability

60 / 100
60 / 100
60 / 100
70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

29 MJ/kg12,468 BTU/lb
32 MJ/kg13,758 BTU/lb
31 MJ/kg13,328 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2.2 kg CO₂/kg
2.3 kg CO₂/kg
2.2 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

30%
30%
30%
35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

106 kN·m/kg
88 kN·m/kg
110 kN·m/kg
92 kN·m/kg

Modulus of Resilience

660 kJ/m³
562 kJ/m³
660 kJ/m³
184 kJ/m³

Thermal Diffusivity

11.5 mm²/s
11.5 mm²/s
11.5 mm²/s
12 mm²/s

Thermal Shock Resistance Index

14
12
15
13

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 scale4140415051604145

Manufacturing and finishing

Capability4145414041505160
Casting & forgingYes
Default conditionHRHRHRAnnealed
Relative cost$$ Standard$$ Standard$$$ Premium$$$ Premium
Min. machined wall0.8 mm0.8 mm0.8 mm0.8 mm
Best machined surfaceRa 1.6 µmRa 1.6 µmRa 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.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4145 and 4140 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.