Stainless Steel ER308Si vs ER317
Stainless Steel · grade comparison
Stainless Steel ER308Si and ER317 are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. On the shop floor, ER308Si machines more easily (fair vs poor) and ER308Si sits in a lower cost tier (premium, $$$) than ER317 (high, $$$$).
ER308SiChoose it when the part is machined in volume, or when cost is the deciding factor.
ER308Si vs ER317: 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
Compressive Strength
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 195 GPa28.3 Msi · Shear Modulus 77 GPa11.2 Msi · Poisson's Ratio 0.29 · Tensile Strength (Ultimate) 600 MPa87 ksi · Yield Strength (0.2% offset) 400 MPa58 ksi · Elongation at Break 38% · Reduction in Area 55% · Shear Strength 400 MPa58 ksi · Fatigue Strength (Endurance Limit) 240 MPa34.8 ksi · Hardness, Rockwell B 88 HRB
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
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.5 µm/m·K9.2 µin/in·°F · Min Service Temperature -196°C-321 °F
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
Brazeability / Solderability
Polishability
Same in both: Formability (cold) 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 55%
Common Calculations
Ratios derived from the values above.
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: Specific Strength (UTS / density) 75 kN·m/kg · Modulus of Resilience 410 kJ/m³ · 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 | ER308Si | ER317 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
ER308Si vs ER317 — frequently asked
What is the difference between ER308Si and ER317?
Stainless Steel ER308Si and ER317 are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. On the shop floor, ER308Si machines more easily (fair vs poor) and ER308Si sits in a lower cost tier (premium, $$$) than ER317 (high, $$$$).
Which is cheaper, ER308Si or ER317?
ER308Si is the lower-cost material: it sits in the premium tier ($$$) while ER317 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, ER308Si or ER317?
ER308Si. Its machinability rates fair (40/100) against poor (30/100) for ER317; for welding the order is ER308Si first (excellent, 95/100) then ER317 (excellent, 88/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ER308Si and ER317 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.