Stainless Steel 418 vs 420
Stainless Steel · grade comparison
Stainless Steel 418 and 420 are both stainless steel grades. 418 is the stronger of the two: yield strength 860 MPa (125 ksi) against 360 MPa (52.2 ksi) for 420, about 139% more; tensile strength follows at 1,070 MPa (155 ksi) vs 690 MPa (100 ksi). In exchange, 420 is the more ductile: elongation 22% versus 18% for 418, and 418 is harder (320 HB vs 200 HB). 418 is stiffer (215 GPa vs 200 GPa) and 420 runs hotter in service (650°C vs 590°C continuous). On the shop floor, 420 machines more easily (45 vs 35 out of 100) and 420 sits in a lower cost tier (premium, $$$) than 418 (high, $$$$).
418Choose it when strength drives the design.
420Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
418 vs 420: 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Hardness, Rockwell B
Same in both: Poisson's Ratio 0.29 · Reduction in Area 55%
Physical
Density and transition temperatures.
Melting Point (Solidus)
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Liquidus Temperature 1,510°C2,750 °F
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
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.3 V
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 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
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 | 418 | 420 |
|---|---|---|
| CNC machining | — | Yes |
| Default condition | — | Annealed |
| Relative cost | $$$$ High | $$$ 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.
418 vs 420 — frequently asked
Is 418 stronger than 420?
Yes. 418 has a typical yield strength of 860 MPa (125 ksi) against 360 MPa (52.2 ksi) for 420 — about 139% more. Tensile strength is 1,070 MPa (155 ksi) vs 690 MPa (100 ksi).
Which is cheaper, 418 or 420?
420 is the lower-cost material: it sits in the premium tier ($$$) while 418 is high ($$$$). 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, 418 or 420?
420, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for 418; for welding the order is 418 first (poor, 30/100) then 420 (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 418 and 420 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.