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Steel 4150 vs CP800

Steel · grade comparison

Steel 4150 and CP800 are both steel grades, both high strength steel. CP800 is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 520 MPa (75.4 ksi) for 4150, about 19% more. In exchange, 4150 is the more ductile: elongation 16% versus 13% for CP800, and CP800 is harder (250 HB vs 235 HB). 4150 runs hotter in service (400°C vs 200°C continuous) and 4150 conducts heat better (42.6 W/m·K vs 38 W/m·K). On the shop floor, 4150 machines more easily (45 vs 35 out of 100), CP800 welds better (very good vs poor), and CP800 sits in a lower cost tier (standard, $$) than 4150 (premium, $$$).

4150Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

CP800Choose it when strength drives the design, or when it will be welded.

4150 vs CP800: properties

4150CP800

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
210 GPa30.5 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

860 MPa125 ksi
840 MPa122 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
620 MPa89.9 ksi

Elongation at Break

16%
13%

Reduction in Area

40%
45%

Shear Strength

560 MPa81.2 ksi
520 MPa75.4 ksi

Fatigue Strength (Endurance Limit)

390 MPa56.6 ksi
380 MPa55.1 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

235 HB
250 HB

Hardness, Rockwell C

21 HRC
25 HRC

Hardness, Vickers

245 HV
265 HV

Compressive Strength

—
840 MPa122 ksi

Fracture Toughness (K_IC)

—
55 MPa·√m50.1 ksi·√in

Hardness, Rockwell B

—
100 HRB

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,416°C2,581 °F
1,460°C2,660 °F

Liquidus Temperature

1,490°C2,714 °F
1,510°C2,750 °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
38 W/m·K22 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

12.3 µm/m·K6.8 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

400°C752 °F
200°C392 °F

Same in both: Min Service Temperature -40°C-40 °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
-0.62 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
35 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
35%

Weldability

25 / 100
70 / 100

Formability (cold)

25 / 100
45 / 100

Castability

35 / 100
—

Polishability

60 / 100
45 / 100

Same in both: Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

31 MJ/kg13,328 BTU/lb
28 MJ/kg12,038 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2.2 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

30%
20%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

110 kN·m/kg
107 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

660 kJ/m³
915 kJ/m³

Thermal Diffusivity

11.5 mm²/s
10.3 mm²/s

Thermal Shock Resistance Index

15
13

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 scale4150CP800

Manufacturing and finishing

Capability4150CP800
CNC machiningYes—
Default conditionHRCR
Relative cost$$$ Premium$$ Standard
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CrNYes—
DLCYes—
HVOF CoatingYes—
MoS2Yes—
Multilayer CVDYes—
TiAlNYes—
TiB2Yes—
TiCNYes—
TiNYes—
WC/CYes—
ZrNYes—

Both are offered for Sheet metal. They share 22 finishes: Black Oxide, Cerakote, Chrome Plating, Copper Plating, E-Coating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Hot-Dip Galvanizing, Manganese Phosphate, Nickel Plating and 10 more.

4150 vs CP800 — frequently asked

Is CP800 stronger than 4150?

Yes. CP800 has a typical yield strength of 620 MPa (89.9 ksi) against 520 MPa (75.4 ksi) for 4150 — about 19% more. Tensile strength is 840 MPa (122 ksi) vs 860 MPa (125 ksi).

Which is cheaper, 4150 or CP800?

CP800 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 CP800?

4150, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for CP800; for welding the order is CP800 first (very good, 70/100) then 4150 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4150 and CP800 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.