Stainless Steel 303Se vs 304
Stainless Steel · grade comparison
Stainless Steel 303Se and 304 are both stainless steel grades. 303Se is the stronger of the two: yield strength 415 MPa (60.2 ksi) against 250 MPa (36.3 ksi) for 304, about 66% more; tensile strength follows at 690 MPa (100 ksi) vs 585 MPa (84.8 ksi). In exchange, 304 is the more ductile: elongation 55% versus 35% for 303Se, and 303Se is harder (228 HB vs 150 HB). 304 runs hotter in service (870°C vs 760°C continuous). On the shop floor, 303Se machines more easily (excellent vs fair) and 304 welds better (excellent vs poor).
303SeChoose it when strength drives the design, or when the part is machined in volume.
304Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
303Se vs 304: 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.
Bulk Modulus
Poisson's Ratio
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: Elastic (Young's) Modulus 193 GPa28 Msi · Shear Modulus 77 GPa11.2 Msi
Physical
Density and transition temperatures.
Density
Liquidus Temperature
Same in both: Melting Point (Solidus) 1,400°C2,552 °F
Thermal
How each material carries heat and how hot it can run.
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Thermal Conductivity 16.2 W/m·K9.4 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 17.3 µm/m·K9.6 µin/in·°F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.4 % IACS · Electrical Resistivity 7.2×10⁻⁷ Ω·m28.3 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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
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
Same in both: Thermal Diffusivity 4.1 mm²/s · Thermal Shock Resistance Index 3
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 | 304 |
|---|---|---|
| Sheet metal | — | Yes |
| Casting & forging | — | Yes |
| 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 304 — frequently asked
Is 303Se stronger than 304?
Yes. 303Se has a typical yield strength of 415 MPa (60.2 ksi) against 250 MPa (36.3 ksi) for 304 — about 66% more. Tensile strength is 690 MPa (100 ksi) vs 585 MPa (84.8 ksi).
Which is cheaper, 303Se or 304?
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 304?
303Se. Its machinability rates excellent (85/100) against fair (45/100) for 304; for welding the order is 304 first (excellent, 88/100) then 303Se (poor, 22/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 303Se and 304 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.