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Steel 45SiCrV6-2 vs 55Cr3

Steel · grade comparison

Steel 45SiCrV6-2 and 55Cr3 are both steel grades. 45SiCrV6-2 is the stronger of the two: yield strength 1,500 MPa (218 ksi) against 480 MPa (69.6 ksi) for 55Cr3, about 3.1 times as much; tensile strength follows at 1,700 MPa (247 ksi) vs 800 MPa (116 ksi). In exchange, 55Cr3 is the more ductile: elongation 16% versus 7% for 45SiCrV6-2, and 45SiCrV6-2 is harder (490 HB vs 225 HB). 55Cr3 runs hotter in service (400°C vs 250°C continuous) and 55Cr3 conducts electricity better (7.8 % IACS vs 7 % IACS). On the shop floor, 55Cr3 machines more easily (fair vs poor) and 55Cr3 welds better (25 vs 15 out of 100).

45SiCrV6-2Choose it when strength drives the design.

55Cr3Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

45SiCrV6-2 vs 55Cr3: properties

45SiCrV6-255Cr3

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

1,700 MPa247 ksi
800 MPa116 ksi

Yield Strength (0.2% offset)

1,500 MPa218 ksi
480 MPa69.6 ksi

Elongation at Break

7%
16%

Reduction in Area

30%
40%

Compressive Strength

1,550 MPa225 ksi
480 MPa69.6 ksi

Shear Strength

1,020 MPa148 ksi
500 MPa72.5 ksi

Fatigue Strength (Endurance Limit)

700 MPa102 ksi
360 MPa52.2 ksi

Fracture Toughness (K_IC)

50 MPa·√m45.5 ksi·√in
85 MPa·√m77.4 ksi·√in

Charpy V-Notch Impact (RT)

20 J14.8 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

490 HB
225 HB

Hardness, Rockwell C

50 HRC
20 HRC

Hardness, Vickers

520 HV
236 HV

Hardness, Rockwell B

—
98 HRB

Same in both: Elastic (Young's) Modulus 206 GPa29.9 Msi · Shear Modulus 79.5 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Density

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

Same in both: Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F

Thermal

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

Thermal Conductivity

42 W/m·K24.3 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.5 µm/m·K6.4 µin/in·°F
12.5 µm/m·K6.9 µin/in·°F

Max Service Temperature (continuous)

250°C482 °F
400°C752 °F

Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7 % IACS
7.8 % IACS

Electrical Resistivity

2.5×10⁻⁷ Ω·m9.84 µΩ·in
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
—

Corrosion Resistance

12 / 100
10 / 100

Manufacturability

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

Machinability

28 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

25%
55%

Weldability

15 / 100
25 / 100

Formability (cold)

8 / 100
45 / 100

Brazeability / Solderability

35 / 100
40 / 100

Same in both: Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
26 MJ/kg11,178 BTU/lb

Embodied Carbon (primary production)

2.1 kg CO₂/kg
2 kg CO₂/kg

Embodied Water

50 L/kg6 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)

218 kN·m/kg
102 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

5,461 kJ/m³
559 kJ/m³

Thermal Diffusivity

11.5 mm²/s
12.1 mm²/s

Thermal Shock Resistance Index

30
14

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 scale55Cr345SiCrV6-2

Manufacturing and finishing

Capability45SiCrV6-255Cr3
CNC machining—Yes
Sheet metal—Yes
Default condition—Annealed
Relative cost$$ Standard$$ Standard
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

45SiCrV6-2 vs 55Cr3 — frequently asked

Is 45SiCrV6-2 stronger than 55Cr3?

Yes. 45SiCrV6-2 has a typical yield strength of 1,500 MPa (218 ksi) against 480 MPa (69.6 ksi) for 55Cr3 — about 3.1 times as much. Tensile strength is 1,700 MPa (247 ksi) vs 800 MPa (116 ksi).

Which is cheaper, 45SiCrV6-2 or 55Cr3?

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, 45SiCrV6-2 or 55Cr3?

55Cr3. Its machinability rates fair (50/100) against poor (28/100) for 45SiCrV6-2; for welding the order is 55Cr3 first (poor, 25/100) then 45SiCrV6-2 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 45SiCrV6-2 and 55Cr3 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.