Stainless Steel 2304 vs S81921
Stainless Steel · grade comparison
Stainless Steel 2304 and S81921 are both stainless steel grades. S81921 is the stronger of the two: yield strength 520 MPa (75.4 ksi) against 460 MPa (66.7 ksi) for 2304, about 13% more; tensile strength follows at 730 MPa (106 ksi) vs 680 MPa (98.6 ksi). S81921 is the more ductile: elongation 35% versus 30% for 2304. On the shop floor, S81921 sits in a lower cost tier (standard, $$) than 2304 (premium, $$$).
S81921Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
2304 vs S81921: 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
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 B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 77 GPa11.2 Msi · Poisson's Ratio 0.3 · Reduction in Area 55%
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
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Thermal Expansion (CTE, 20–100 °C) 13 µm/m·K7.2 µin/in·°F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.15 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Same in both: Formability (cold) 55 / 100 · Polishability 70 / 100
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
Same in both: Thermal Shock Resistance Index 4
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 | 2304 | S81921 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | Solution Annealed | — |
| Relative cost | $$$ Premium | $$ Standard |
| 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.
2304 vs S81921 — frequently asked
Is S81921 stronger than 2304?
Yes. S81921 has a typical yield strength of 520 MPa (75.4 ksi) against 460 MPa (66.7 ksi) for 2304 — about 13% more. Tensile strength is 730 MPa (106 ksi) vs 680 MPa (98.6 ksi).
Which is cheaper, 2304 or S81921?
S81921 is the lower-cost material: it sits in the standard tier ($$) while 2304 is premium ($$$). 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, 2304 or S81921?
S81921, by a small margin. Both rate fair for machinability — 40/100 against 35/100 for 2304.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2304 and S81921 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.