Stainless Steel 904L vs Alloy 20
Stainless Steel · grade comparison
Stainless Steel 904L and Alloy 20 are both stainless steel grades, both corrosion resistant ss. Alloy 20 is the stronger of the two: yield strength 310 MPa (45 ksi) against 260 MPa (37.7 ksi) for 904L, about 19% more. Alloy 20 is harder — 85 HRB against 80 HRB for 904L — which matters for wear surfaces and threads. Alloy 20 runs hotter in service (500°C vs 400°C continuous). On the shop floor, Alloy 20 machines more easily (fair vs poor) and 904L sits in a lower cost tier (premium, $$$) than Alloy 20 (specialty, $$$$$).
904LChoose it when cost is the deciding factor.
Alloy 20Choose it when strength drives the design, or when surface hardness matters.
904L 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 12 W/m·K6.9 BTU/hr·ft·°F · 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
Brazeability / Solderability
Polishability
Castability
Same in both: Formability (cold) 72 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Typical Recycled Content
Same in both: Embodied Water 200 L/kg24 gal/lb
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 | 904L | Alloy 20 |
|---|---|---|
| Default condition | Solution Annealed | Annealed |
| Relative cost | $$$ Premium | $$$$$ Specialty |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.
904L vs Alloy 20 — frequently asked
Is Alloy 20 stronger than 904L?
Yes. Alloy 20 has a typical yield strength of 310 MPa (45 ksi) against 260 MPa (37.7 ksi) for 904L — about 19% more. Tensile strength is 620 MPa (89.9 ksi) vs 590 MPa (85.6 ksi).
Which is cheaper, 904L or Alloy 20?
904L is the lower-cost material: it sits in the premium tier ($$$) 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, 904L or Alloy 20?
Alloy 20. Its machinability rates fair (38/100) against poor (28/100) for 904L.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 904L 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.