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Steel 55Cr3 vs P420ML1

Steel · grade comparison

Steel 55Cr3 and P420ML1 are both steel grades. 55Cr3 is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 450 MPa (65.3 ksi) for P420ML1, about 7% more; tensile strength follows at 800 MPa (116 ksi) vs 560 MPa (81.2 ksi). In exchange, P420ML1 is the more ductile: elongation 25% versus 16% for 55Cr3, and 55Cr3 is harder (225 HB vs 175 HB). On the shop floor, P420ML1 welds better (excellent vs poor) and P420ML1 sits in a lower cost tier (budget, $) than 55Cr3 (standard, $$).

55Cr3Choose it when strength drives the design.

P420ML1Choose it when the part is bent, formed or impact-loaded, or when it will be welded.

55Cr3 vs P420ML1: properties

55Cr3P420ML1

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

206 GPa29.9 Msi
210 GPa30.5 Msi

Shear Modulus

79.5 GPa11.5 Msi
81 GPa11.7 Msi

Bulk Modulus

160 GPa23.2 Msi
165 GPa23.9 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

800 MPa116 ksi
560 MPa81.2 ksi

Yield Strength (0.2% offset)

480 MPa69.6 ksi
450 MPa65.3 ksi

Elongation at Break

16%
25%

Reduction in Area

40%
60%

Compressive Strength

480 MPa69.6 ksi
450 MPa65.3 ksi

Shear Strength

500 MPa72.5 ksi
340 MPa49.3 ksi

Fatigue Strength (Endurance Limit)

360 MPa52.2 ksi
250 MPa36.3 ksi

Fracture Toughness (K_IC)

85 MPa·√m77.4 ksi·√in
150 MPa·√m137 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
190 J140 ft·lbf

Hardness, Brinell

225 HB
175 HB

Hardness, Rockwell B

98 HRB
89 HRB

Hardness, Rockwell C

20 HRC
—

Hardness, Vickers

236 HV
185 HV

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °F
1,490°C2,714 °F

Liquidus Temperature

1,490°C2,714 °F
1,520°C2,768 °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

44 W/m·K25.4 BTU/hr·ft·°F
45 W/m·K26 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 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

Same in both: Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
8.6 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2×10⁻⁷ Ω·m7.87 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

10 / 100
12 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.65 V

Manufacturability

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

Machinability

50 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
60%

Weldability

25 / 100
88 / 100

Formability (cold)

45 / 100
65 / 100

Brazeability / Solderability

40 / 100
55 / 100

Polishability

60 / 100
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

26 MJ/kg11,178 BTU/lb
28 MJ/kg12,038 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

45 L/kg5.4 gal/lb
50 L/kg6 gal/lb

Typical Recycled Content

30%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

102 kN·m/kg
71 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

559 kJ/m³
482 kJ/m³

Thermal Diffusivity

12.1 mm²/s
12.5 mm²/s

Thermal Shock Resistance Index

14
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 scale55Cr3P420ML1

Manufacturing and finishing

Capability55Cr3P420ML1
CNC machiningYes—
Sheet metalYes—
Default conditionAnnealed—
Relative cost$$ Standard$ Budget
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

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

55Cr3 vs P420ML1 — frequently asked

Is 55Cr3 stronger than P420ML1?

Yes. 55Cr3 has a typical yield strength of 480 MPa (69.6 ksi) against 450 MPa (65.3 ksi) for P420ML1 — about 7% more. Tensile strength is 800 MPa (116 ksi) vs 560 MPa (81.2 ksi).

Which is cheaper, 55Cr3 or P420ML1?

P420ML1 is the lower-cost material: it sits in the budget tier ($) while 55Cr3 is standard ($$). 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, 55Cr3 or P420ML1?

P420ML1. Its machinability rates good (55/100) against fair (50/100) for 55Cr3; for welding the order is P420ML1 first (excellent, 88/100) then 55Cr3 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 55Cr3 and P420ML1 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.