Stainless Steel 303Se vs 420F
Stainless Steel · grade comparison
Stainless Steel 303Se and 420F are both stainless steel grades, both machining-friendly ss. 303Se is the stronger of the two: yield strength 415 MPa (60.2 ksi) against 380 MPa (55.1 ksi) for 420F, about 9% more. 303Se is the more ductile: elongation 35% versus 20% for 420F. 303Se runs hotter in service (760°C vs 400°C continuous) and 420F conducts heat better (24.9 W/m·K vs 16.2 W/m·K). On the shop floor, 303Se machines more easily (excellent vs good) and 303Se welds better (poor vs not recommended).
303SeChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
303Se vs 420F: 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
Poisson's Ratio
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Tensile Strength (Ultimate) 690 MPa100 ksi · Fatigue Strength (Endurance Limit) 300 MPa43.5 ksi
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)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
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
Polishability
Castability
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 | 303Se | 420F |
|---|---|---|
| Default condition | Cold Drawn | Annealed |
| Relative cost | $$ Standard | $$ Standard |
| 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. 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.
303Se vs 420F — frequently asked
Is 303Se stronger than 420F?
Yes. 303Se has a typical yield strength of 415 MPa (60.2 ksi) against 380 MPa (55.1 ksi) for 420F — about 9% more. Tensile strength is 690 MPa (100 ksi) vs 690 MPa (100 ksi).
Which is cheaper, 303Se or 420F?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 303Se or 420F?
303Se. Its machinability rates excellent (85/100) against good (58/100) for 420F; for welding the order is 303Se first (poor, 22/100) then 420F (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 303Se and 420F 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.