Stainless Steel ER308 vs ER385
Stainless Steel · grade comparison
Stainless Steel ER308 and ER385 are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. ER385 is harder — 195 HB against 185 HB for ER308 — which matters for wear surfaces and threads. ER308 runs hotter in service (760°C vs 400°C continuous) and ER308 conducts heat better (15.5 W/m·K vs 11.5 W/m·K). On the shop floor, ER308 machines more easily (fair vs poor), ER308 welds better (excellent vs very good), and ER385 forms better (very good vs good).
ER308Choose it when the part sees heat, or when the part is machined in volume.
ER385Choose it when surface hardness matters.
ER308 vs ER385: 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
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Poisson's Ratio 0.3 · Tensile Strength (Ultimate) 600 MPa87 ksi · Reduction in Area 55% · Shear Strength 400 MPa58 ksi · Fatigue Strength (Endurance Limit) 240 MPa34.8 ksi · Charpy V-Notch Impact (RT) 90 J66.4 ft·lbf
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)
Same in both: 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
Formability (cold)
Brazeability / Solderability
Same in both: Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 45%
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 | ER308 | ER385 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
ER308 vs ER385 — frequently asked
What is the difference between ER308 and ER385?
Stainless Steel ER308 and ER385 are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. ER385 is harder — 195 HB against 185 HB for ER308 — which matters for wear surfaces and threads.
Which is cheaper, ER308 or ER385?
ER308 is the lower-cost material: it sits in the premium tier ($$$) while ER385 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, ER308 or ER385?
ER308. Its machinability rates fair (38/100) against poor (28/100) for ER385; for welding the order is ER308 first (excellent, 95/100) then ER385 (very good, 80/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ER308 and ER385 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.