Stainless Steel Alloy 20 vs Alloy 803
Stainless Steel · grade comparison
Stainless Steel Alloy 20 and Alloy 803 are both stainless steel grades. Alloy 20 is the stronger of the two: yield strength 310 MPa (45 ksi) against 265 MPa (38.4 ksi) for Alloy 803, about 17% more; tensile strength follows at 620 MPa (89.9 ksi) vs 585 MPa (84.8 ksi). In exchange, Alloy 803 is the more ductile: elongation 45% versus 40% for Alloy 20. Alloy 803 runs hotter in service (1,100°C vs 500°C continuous). On the shop floor, Alloy 20 machines more easily (fair vs poor), Alloy 20 welds better (very good vs good), and Alloy 803 sits in a lower cost tier (high, $$$$) than Alloy 20 (specialty, $$$$$).
Alloy 20Choose it when strength drives the design, or when the part is machined in volume.
Alloy 803Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Alloy 20 vs Alloy 803: 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 193 GPa28 Msi · Shear Modulus 74 GPa10.7 Msi · 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.
Thermal Conductivity
Specific Heat Capacity
Max Service Temperature (continuous)
Same in both: Thermal Expansion (CTE, 20–100 °C) 14.8 µm/m·K8.2 µin/in·°F · Latent Heat of Fusion 285 J/g123 BTU/lb · 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)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 100 MJ/kg42,992 BTU/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 | Alloy 20 | Alloy 803 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Annealed | — |
| Relative cost | $$$$$ Specialty | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
Alloy 20 vs Alloy 803 — frequently asked
Is Alloy 20 stronger than Alloy 803?
Yes. Alloy 20 has a typical yield strength of 310 MPa (45 ksi) against 265 MPa (38.4 ksi) for Alloy 803 — about 17% more. Tensile strength is 620 MPa (89.9 ksi) vs 585 MPa (84.8 ksi).
Which is cheaper, Alloy 20 or Alloy 803?
Alloy 803 is the lower-cost material: it sits in the high tier ($$$$) while Alloy 20 is specialty ($$$$$). 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, Alloy 20 or Alloy 803?
Alloy 20. Its machinability rates fair (38/100) against poor (27/100) for Alloy 803; for welding the order is Alloy 20 first (very good, 80/100) then Alloy 803 (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Alloy 20 and Alloy 803 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.