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Stainless Steel 20Cb-3 vs 904L

Stainless Steel · grade comparison

Stainless Steel 20Cb-3 and 904L are both stainless steel grades. 20Cb-3 is the stronger of the two: yield strength 345 MPa (50 ksi) against 260 MPa (37.7 ksi) for 904L, about 33% more. 20Cb-3 runs hotter in service (500°C vs 400°C continuous).

20Cb-3Choose it when strength drives the design, or when the part sees heat.

20Cb-3 vs 904L: properties

20Cb-3904L

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

193 GPa28 Msi
195 GPa28.3 Msi

Shear Modulus

74 GPa10.7 Msi
75 GPa10.9 Msi

Bulk Modulus

161 GPa23.4 Msi
160 GPa23.2 Msi

Tensile Strength (Ultimate)

620 MPa89.9 ksi
590 MPa85.6 ksi

Yield Strength (0.2% offset)

345 MPa50 ksi
260 MPa37.7 ksi

Reduction in Area

60%
65%

Shear Strength

400 MPa58 ksi
390 MPa56.6 ksi

Fatigue Strength (Endurance Limit)

275 MPa39.9 ksi
240 MPa34.8 ksi

Charpy V-Notch Impact (RT)

200 J148 ft·lbf
180 J133 ft·lbf

Hardness, Brinell

160 HB
155 HB

Hardness, Rockwell B

83 HRB
80 HRB

Hardness, Vickers

170 HV
165 HV

Compressive Strength

—
265 MPa38.4 ksi

Fracture Toughness (K_IC)

—
200 MPa·√m182 ksi·√in

Same in both: Poisson's Ratio 0.3 · Elongation at Break 42%

Physical

Density and transition temperatures.

Density

8.08 g/cm³0.29 lb/in³
8 g/cm³0.29 lb/in³

Melting Point (Solidus)

1,425°C2,597 °F
1,300°C2,372 °F

Liquidus Temperature

1,445°C2,633 °F
1,390°C2,534 °F

Thermal

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

Thermal Conductivity

12.6 W/m·K7.3 BTU/hr·ft·°F
12 W/m·K6.9 BTU/hr·ft·°F

Specific Heat Capacity

500 J/kg·K0.12 BTU/lb·°F
450 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

14.8 µm/m·K8.2 µin/in·°F
15.3 µm/m·K8.5 µin/in·°F

Max Service Temperature (continuous)

500°C932 °F
400°C752 °F

Latent Heat of Fusion

—
270 J/g116 BTU/lb

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.6 % IACS
1.7 % IACS

Electrical Resistivity

1.08×10⁻⁶ Ω·m42.5 µΩ·in
1×10⁻⁶ Ω·m39.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.1 V
-0.05 V

Corrosion Resistance

72 / 100
82 / 100

Manufacturability

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

Machinability

33 / 100
28 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
30%

Weldability

75 / 100
78 / 100

Formability (cold)

70 / 100
72 / 100

Polishability

75 / 100
78 / 100

Same in both: Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

110 MJ/kg47,292 BTU/lb
78 MJ/kg33,534 BTU/lb

Embodied Carbon (primary production)

7.5 kg CO₂/kg
5.6 kg CO₂/kg

Embodied Water

150 L/kg18 gal/lb
200 L/kg24 gal/lb

Typical Recycled Content

40%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

77 kN·m/kg
74 kN·m/kg

Specific Stiffness (E / density)

23.9 MN·m/kg
24.4 MN·m/kg

Modulus of Resilience

308 kJ/m³
173 kJ/m³

Thermal Diffusivity

3.1 mm²/s
3.3 mm²/s

Thermal Shock Resistance Index

3
2

Strength versus weight

Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scale20Cb-3904L

Manufacturing and finishing

Capability20Cb-3904L
Default conditionSolution AnnealedSolution Annealed
Relative cost$$$ Premium$$$ Premium
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 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.

20Cb-3 vs 904L — frequently asked

Is 20Cb-3 stronger than 904L?

Yes. 20Cb-3 has a typical yield strength of 345 MPa (50 ksi) against 260 MPa (37.7 ksi) for 904L — about 33% more. Tensile strength is 620 MPa (89.9 ksi) vs 590 MPa (85.6 ksi).

Which is cheaper, 20Cb-3 or 904L?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, 20Cb-3 or 904L?

20Cb-3, by a small margin. Both rate poor for machinability — 33/100 against 28/100 for 904L.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 20Cb-3 and 904L 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.