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Stainless Steel E308 vs ER308LSi

Stainless Steel · grade comparison

Stainless Steel E308 and ER308LSi are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. E308 is harder — 180 HB against 165 HB for ER308LSi — which matters for wear surfaces and threads. E308 runs hotter in service (760°C vs 425°C continuous). On the shop floor, ER308LSi forms better (very good vs good).

E308Choose it when surface hardness matters, or when the part sees heat.

E308 vs ER308LSi: properties

E308ER308LSi

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

193 GPa28 Msi
195 GPa28.3 Msi

Shear Modulus

77 GPa11.2 Msi
75 GPa10.9 Msi

Bulk Modulus

140 GPa20.3 Msi
152 GPa22 Msi

Elongation at Break

40%
38%

Shear Strength

400 MPa58 ksi
370 MPa53.7 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 ksi
250 MPa36.3 ksi

Fracture Toughness (K_IC)

120 MPa·√m109 ksi·√in
160 MPa·√m146 ksi·√in

Charpy V-Notch Impact (RT)

75 J55.3 ft·lbf
80 J59 ft·lbf

Hardness, Brinell

180 HB
165 HB

Hardness, Rockwell B

88 HRB
85 HRB

Hardness, Vickers

190 HV
180 HV

Compressive Strength

—
400 MPa58 ksi

Same in both: Poisson's Ratio 0.29 · Tensile Strength (Ultimate) 580 MPa84.1 ksi · Yield Strength (0.2% offset) 400 MPa58 ksi · Reduction in Area 55%

Physical

Density and transition temperatures.

Same in both: Density 7.9 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,450°C2,642 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

15.5 W/m·K9 BTU/hr·ft·°F
15 W/m·K8.7 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

16.6 µm/m·K9.2 µin/in·°F
16.5 µm/m·K9.2 µin/in·°F

Latent Heat of Fusion

280 J/g120 BTU/lb
270 J/g116 BTU/lb

Max Service Temperature (continuous)

760°C1,400 °F
425°C797 °F

Min Service Temperature

-100°C-148 °F
-196°C-321 °F

Same in both: Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.4 % IACS
2.3 % IACS

Electrical Resistivity

7.2×10⁻⁷ Ω·m28.3 µΩ·in
7.4×10⁻⁷ Ω·m29.1 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

68 / 100
66 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.08 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Weldability

92 / 100
95 / 100

Formability (cold)

60 / 100
70 / 100

Brazeability / Solderability

55 / 100
60 / 100

Polishability

70 / 100
65 / 100

Same in both: Machinability 38 / 100 · Machinability Rating (AISI 1212 = 100 %) 40%

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
60 MJ/kg25,795 BTU/lb

Embodied Carbon (primary production)

4.5 kg CO₂/kg
5.5 kg CO₂/kg

Embodied Water

120 L/kg14.4 gal/lb
130 L/kg15.6 gal/lb

Typical Recycled Content

60%
65%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

24.4 MN·m/kg
24.7 MN·m/kg

Modulus of Resilience

415 kJ/m³
410 kJ/m³

Thermal Diffusivity

3.9 mm²/s
3.8 mm²/s

Same in both: Specific Strength (UTS / density) 73 kN·m/kg · 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.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scaleER308LSiE308

Manufacturing and finishing

CapabilityE308ER308LSi
Default condition——
Relative cost$$$ Premium$$$ Premium
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.

E308 vs ER308LSi — frequently asked

What is the difference between E308 and ER308LSi?

Stainless Steel E308 and ER308LSi are both stainless steel grades. Both yield at about 400 MPa — strength does not separate them. E308 is harder — 180 HB against 165 HB for ER308LSi — which matters for wear surfaces and threads.

Which is cheaper, E308 or ER308LSi?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

When should I choose E308 over ER308LSi?

Pick E308 when surface hardness matters, or when the part sees heat.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E308 and ER308LSi 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.