Stainless Steel 27-7Mo vs Alloy 20
Stainless Steel · grade comparison
Stainless Steel 27-7Mo and Alloy 20 are both stainless steel grades. 27-7Mo is the stronger of the two: yield strength 405 MPa (58.7 ksi) against 310 MPa (45 ksi) for Alloy 20, about 31% more; tensile strength follows at 800 MPa (116 ksi) vs 620 MPa (89.9 ksi). 27-7Mo is the more ductile: elongation 50% versus 40% for Alloy 20, and 27-7Mo is harder (200 HB vs 160 HB). Alloy 20 runs hotter in service (500°C vs 400°C continuous). On the shop floor, Alloy 20 machines more easily (fair vs poor), Alloy 20 welds better (very good vs good), and 27-7Mo sits in a lower cost tier (high, $$$$) than Alloy 20 (specialty, $$$$$).
27-7MoChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Alloy 20Choose it when the part sees heat, or when the part is machined in volume.
27-7Mo vs Alloy 20: 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Poisson's Ratio 0.3 · Reduction in Area 60%
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
Castability
Same in both: Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: 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 | 27-7Mo | Alloy 20 |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Default condition | — | Annealed |
| Relative cost | $$$$ High | $$$$$ Specialty |
| Min. machined wall | — | 0.8 mm |
| Best machined surface | — | Ra 1.6 µm |
| AlCrN | — | Yes |
| AlTiN | — | Yes |
| Black Oxide | — | Yes |
| CVD Al2O3 | — | Yes |
| CVD TiCN | — | Yes |
| CVD TiN | — | Yes |
| Cerakote | — | Yes |
| Chrome Plating | — | Yes |
| CrN | — | Yes |
| DLC | — | Yes |
| Electropolishing | — | Yes |
| HVOF Coating | — | Yes |
| MoS2 | — | Yes |
| Multilayer CVD | — | Yes |
| Nickel Plating | — | Yes |
| PTFE Coating | — | Yes |
| Painting | — | Yes |
| Passivation (Stainless Steel) | — | Yes |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
27-7Mo vs Alloy 20 — frequently asked
Is 27-7Mo stronger than Alloy 20?
Yes. 27-7Mo has a typical yield strength of 405 MPa (58.7 ksi) against 310 MPa (45 ksi) for Alloy 20 — about 31% more. Tensile strength is 800 MPa (116 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, 27-7Mo or Alloy 20?
27-7Mo is the lower-cost material: it sits in the high tier ($$$$) while Alloy 20 is specialty ($$$$$). 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, 27-7Mo or Alloy 20?
Alloy 20. Its machinability rates fair (38/100) against poor (18/100) for 27-7Mo; for welding the order is Alloy 20 first (very good, 80/100) then 27-7Mo (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 27-7Mo and Alloy 20 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.