Stainless Steel 20Cb-3 vs 654 SMO
Stainless Steel · grade comparison
Stainless Steel 20Cb-3 and 654 SMO are both stainless steel grades. 654 SMO is the stronger of the two: yield strength 490 MPa (71.1 ksi) against 345 MPa (50 ksi) for 20Cb-3, about 42% more; tensile strength follows at 820 MPa (119 ksi) vs 620 MPa (89.9 ksi). 654 SMO is the more ductile: elongation 50% versus 42% for 20Cb-3, and 654 SMO is harder (220 HB vs 160 HB). 20Cb-3 runs hotter in service (500°C vs 400°C continuous) and 20Cb-3 conducts heat better (12.6 W/m·K vs 8.6 W/m·K). On the shop floor, 20Cb-3 machines more easily (33 vs 18 out of 100), 20Cb-3 welds better (very good vs good), and 20Cb-3 sits in a lower cost tier (premium, $$$) than 654 SMO (high, $$$$).
20Cb-3Choose it when the part sees heat, or when the part is machined in volume.
654 SMOChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
20Cb-3 vs 654 SMO: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all stainless steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Poisson's Ratio 0.3 · Charpy V-Notch Impact (RT) 200 J148 ft·lbf
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Latent Heat of Fusion
Same in both: Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 40%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 20Cb-3 | 654 SMO |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Solution Annealed | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
20Cb-3 vs 654 SMO — frequently asked
Is 654 SMO stronger than 20Cb-3?
Yes. 654 SMO has a typical yield strength of 490 MPa (71.1 ksi) against 345 MPa (50 ksi) for 20Cb-3 — about 42% more. Tensile strength is 820 MPa (119 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, 20Cb-3 or 654 SMO?
20Cb-3 is the lower-cost material: it sits in the premium tier ($$$) while 654 SMO is high ($$$$). 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, 20Cb-3 or 654 SMO?
20Cb-3, by a small margin. Both rate poor for machinability — 33/100 against 18/100 for 654 SMO; for welding the order is 20Cb-3 first (very good, 75/100) then 654 SMO (good, 60/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20Cb-3 and 654 SMO 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.