Stainless Steel 20Cb-3 vs 27-7Mo
Stainless Steel · grade comparison
Stainless Steel 20Cb-3 and 27-7Mo are both stainless steel grades. 27-7Mo is the stronger of the two: yield strength 405 MPa (58.7 ksi) against 345 MPa (50 ksi) for 20Cb-3, about 17% more; tensile strength follows at 800 MPa (116 ksi) vs 620 MPa (89.9 ksi). 27-7Mo is the more ductile: elongation 50% versus 42% for 20Cb-3, and 27-7Mo is harder (200 HB vs 160 HB). 20Cb-3 runs hotter in service (500°C vs 400°C continuous). 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, $$$) than 27-7Mo (high, $$$$).
20Cb-3Choose it when the part sees heat, or when the part is machined in volume.
27-7MoChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
20Cb-3 vs 27-7Mo: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Fracture Toughness (K_IC)
Same in both: Poisson's Ratio 0.3 · Reduction in Area 60% · 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)
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).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V
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
Same in both: Polishability 75 / 100
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 | 27-7Mo |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Solution Annealed | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
20Cb-3 vs 27-7Mo — frequently asked
Is 27-7Mo stronger than 20Cb-3?
Yes. 27-7Mo has a typical yield strength of 405 MPa (58.7 ksi) against 345 MPa (50 ksi) for 20Cb-3 — about 17% more. Tensile strength is 800 MPa (116 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, 20Cb-3 or 27-7Mo?
20Cb-3 is the lower-cost material: it sits in the premium tier ($$$) while 27-7Mo 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 27-7Mo?
20Cb-3, by a small margin. Both rate poor for machinability — 33/100 against 18/100 for 27-7Mo; for welding the order is 20Cb-3 first (very good, 75/100) then 27-7Mo (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20Cb-3 and 27-7Mo 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.