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Steel 4150 vs 4815

Steel · grade comparison

Steel 4150 and 4815 are both steel grades. 4150 is the stronger of the two: yield strength 520 MPa (75.4 ksi) against 420 MPa (60.9 ksi) for 4815, about 24% more; tensile strength follows at 860 MPa (125 ksi) vs 690 MPa (100 ksi). In exchange, 4815 is the more ductile: elongation 22% versus 16% for 4150, and 4150 is harder (235 HB vs 200 HB). 4150 conducts heat better (42.6 W/m·K vs 35 W/m·K). On the shop floor, 4815 welds better (good vs poor) and 4815 sits in a lower cost tier (standard, $$) than 4150 (premium, $$$).

4150Choose it when strength drives the design.

4815Choose it when the part is bent, formed or impact-loaded, or when it will be welded.

4150 vs 4815: properties

41504815

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

860 MPa125 ksi
690 MPa100 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
420 MPa60.9 ksi

Elongation at Break

16%
22%

Reduction in Area

40%
50%

Shear Strength

560 MPa81.2 ksi
450 MPa65.3 ksi

Fatigue Strength (Endurance Limit)

390 MPa56.6 ksi
310 MPa45 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
60 J44.3 ft·lbf

Hardness, Brinell

235 HB
200 HB

Hardness, Rockwell C

21 HRC
—

Hardness, Vickers

245 HV
210 HV

Compressive Strength

—
420 MPa60.9 ksi

Fracture Toughness (K_IC)

—
95 MPa·√m86.5 ksi·√in

Hardness, Rockwell B

—
93 HRB

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.

Density

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

Melting Point (Solidus)

1,416°C2,581 °F
1,425°C2,597 °F

Liquidus Temperature

1,490°C2,714 °F
1,495°C2,723 °F

Thermal

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

Thermal Conductivity

42.6 W/m·K24.6 BTU/hr·ft·°F
35 W/m·K20.2 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

250 J/g107 BTU/lb
270 J/g116 BTU/lb

Min Service Temperature

-40°C-40 °F
-70°C-94 °F

Same in both: Max Service Temperature (continuous) 400°C752 °F

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
—

Same in both: Corrosion Resistance 12 / 100

Manufacturability

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

Machinability

45 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
55%

Weldability

25 / 100
55 / 100

Formability (cold)

25 / 100
55 / 100

Castability

35 / 100
—

Brazeability / Solderability

55 / 100
60 / 100

Same in both: Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

31 MJ/kg13,328 BTU/lb
32 MJ/kg13,758 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

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

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

110 kN·m/kg
88 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26 MN·m/kg

Modulus of Resilience

660 kJ/m³
430 kJ/m³

Thermal Diffusivity

11.5 mm²/s
9.6 mm²/s

Thermal Shock Resistance Index

15
10

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 scale41504815

Manufacturing and finishing

Capability41504815
Default conditionHRHR
Relative cost$$$ Premium$$ 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.

4150 vs 4815 — frequently asked

Is 4150 stronger than 4815?

Yes. 4150 has a typical yield strength of 520 MPa (75.4 ksi) against 420 MPa (60.9 ksi) for 4815 — about 24% more. Tensile strength is 860 MPa (125 ksi) vs 690 MPa (100 ksi).

Which is cheaper, 4150 or 4815?

4815 is the lower-cost material: it sits in the standard tier ($$) while 4150 is premium ($$$). 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, 4150 or 4815?

4815, by a small margin. Both rate fair for machinability — 50/100 against 45/100 for 4150; for welding the order is 4815 first (good, 55/100) then 4150 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4150 and 4815 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.