Stainless Steel 20Cb-3 vs S31266
Stainless Steel · grade comparison
Stainless Steel 20Cb-3 and S31266 are both stainless steel grades. S31266 is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 345 MPa (50 ksi) for 20Cb-3, about 39% more; tensile strength follows at 810 MPa (117 ksi) vs 620 MPa (89.9 ksi). S31266 is harder — 215 HB against 160 HB for 20Cb-3 — which matters for wear surfaces and threads. 20Cb-3 runs hotter in service (500°C vs 400°C continuous) and 20Cb-3 conducts heat better (12.6 W/m·K vs 11 W/m·K). On the shop floor, 20Cb-3 machines more easily (33 vs 22 out of 100), 20Cb-3 forms better (very good vs fair), and 20Cb-3 sits in a lower cost tier (premium, $$$) than S31266 (high, $$$$).
20Cb-3Choose it when the part sees heat, or when the part is machined in volume.
S31266Choose it when strength drives the design, or when surface hardness matters.
20Cb-3 vs S31266: 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
Compressive Strength
Fracture Toughness (K_IC)
Hardness, Rockwell C
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
Same in both: Thermal Diffusivity 3.1 mm²/s · Thermal Shock Resistance Index 3
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 | S31266 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Solution Annealed | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
20Cb-3 vs S31266 — frequently asked
Is S31266 stronger than 20Cb-3?
Yes. S31266 has a typical yield strength of 480 MPa (69.6 ksi) against 345 MPa (50 ksi) for 20Cb-3 — about 39% more. Tensile strength is 810 MPa (117 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, 20Cb-3 or S31266?
20Cb-3 is the lower-cost material: it sits in the premium tier ($$$) while S31266 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 S31266?
20Cb-3, by a small margin. Both rate poor for machinability — 33/100 against 22/100 for S31266; for welding the order is 20Cb-3 first (very good, 75/100) then S31266 (very good, 70/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20Cb-3 and S31266 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.