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Stainless Steel E347 vs ER308Si

Stainless Steel · grade comparison

Stainless Steel E347 and ER308Si are both stainless steel grades. Both yield at about 420 MPa — strength does not separate them.

E347 vs ER308Si: properties

E347ER308Si

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

140 GPa20.3 Msi
160 GPa23.2 Msi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
400 MPa58 ksi

Elongation at Break

37%
38%

Compressive Strength

420 MPa60.9 ksi
400 MPa58 ksi

Shear Strength

370 MPa53.7 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

130 MPa·√m118 ksi·√in
140 MPa·√m127 ksi·√in

Charpy V-Notch Impact (RT)

70 J51.6 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

180 HB
175 HB

Hardness, Rockwell B

89 HRB
88 HRB

Hardness, Vickers

190 HV
185 HV

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 · Reduction in Area 55% · Fatigue Strength (Endurance Limit) 240 MPa34.8 ksi

Physical

Density and transition temperatures.

Density

7.9 g/cm³0.29 lb/in³
7.95 g/cm³0.29 lb/in³

Same in both: 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

16 W/m·K9.2 BTU/hr·ft·°F
15 W/m·K8.7 BTU/hr·ft·°F

Max Service Temperature (continuous)

800°C1,472 °F
760°C1,400 °F

Min Service Temperature

-120°C-184 °F
-196°C-321 °F

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 · Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Electrical Resistivity

7.3×10⁻⁷ Ω·m28.7 µΩ·in
7.2×10⁻⁷ Ω·m28.3 µΩ·in

Same in both: Electrical Conductivity 2.4 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.05 V
-0.08 V

Same in both: Corrosion Resistance 68 / 100

Manufacturability

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

Machinability

38 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
45%

Weldability

88 / 100
95 / 100

Formability (cold)

55 / 100
60 / 100

Polishability

65 / 100
70 / 100

Same in both: Brazeability / Solderability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

5.3 kg CO₂/kg
5.5 kg CO₂/kg

Embodied Water

130 L/kg15.6 gal/lb
200 L/kg24 gal/lb

Typical Recycled Content

50%
55%

Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

76 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

24.7 MN·m/kg
24.5 MN·m/kg

Modulus of Resilience

452 kJ/m³
410 kJ/m³

Thermal Diffusivity

4.1 mm²/s
3.8 mm²/s

Same in both: 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 scaleER308SiE347

Manufacturing and finishing

CapabilityE347ER308Si
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.

E347 vs ER308Si — frequently asked

What is the difference between E347 and ER308Si?

Stainless Steel E347 and ER308Si are both stainless steel grades. Both yield at about 420 MPa — strength does not separate them.

Which is cheaper, E347 or ER308Si?

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.

Which welds better, E347 or ER308Si?

ER308Si. Its weldability rates excellent (95/100) against excellent (88/100) for E347.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E347 and ER308Si 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.