Stainless Steel 420 vs AUS-8
Stainless Steel · grade comparison
Stainless Steel 420 and AUS-8 are both stainless steel grades. AUS-8 is the stronger of the two: yield strength 450 MPa (65.3 ksi) against 360 MPa (52.2 ksi) for 420, about 25% more; tensile strength follows at 760 MPa (110 ksi) vs 690 MPa (100 ksi). In exchange, 420 is the more ductile: elongation 22% versus 18% for AUS-8, and AUS-8 is harder (225 HB vs 200 HB). 420 runs hotter in service (650°C vs 400°C continuous).
420Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
AUS-8Choose it when strength drives the design.
420 vs AUS-8: 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
Compressive Strength
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Fatigue Strength (Endurance Limit) 350 MPa50.8 ksi · Fracture Toughness (K_IC) 60 MPa·√m54.6 ksi·√in
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 7.75 g/cm³0.28 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 5.5×10⁻⁷ Ω·m21.7 µΩ·in
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
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 45%
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)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 25.8 MN·m/kg
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 | 420 | AUS-8 |
|---|---|---|
| CNC machining | Yes | — |
| Default condition | Annealed | — |
| Relative cost | $$$ Premium | $$$ Premium |
| 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.
420 vs AUS-8 — frequently asked
Is AUS-8 stronger than 420?
Yes. AUS-8 has a typical yield strength of 450 MPa (65.3 ksi) against 360 MPa (52.2 ksi) for 420 — about 25% more. Tensile strength is 760 MPa (110 ksi) vs 690 MPa (100 ksi).
Which is cheaper, 420 or AUS-8?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 420 or AUS-8?
420, by a small margin. Both rate fair for machinability — 45/100 against 40/100 for AUS-8; for welding the order is 420 first (poor, 25/100) then AUS-8 (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420 and AUS-8 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.