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Stainless Steel E383 vs ER308Si

Stainless Steel · grade comparison

Stainless Steel E383 and ER308Si are both stainless steel grades. Both yield at about 390 MPa — strength does not separate them. E383 is harder — 185 HB against 175 HB for ER308Si — which matters for wear surfaces and threads. ER308Si runs hotter in service (760°C vs 500°C continuous) and ER308Si conducts heat better (15 W/m·K vs 11.5 W/m·K). On the shop floor, ER308Si machines more easily (fair vs poor), ER308Si welds better (excellent vs very good), and ER308Si sits in a lower cost tier (premium, $$$) than E383 (high, $$$$).

E383Choose it when surface hardness matters.

ER308SiChoose it when the part sees heat, or when the part is machined in volume.

E383 vs ER308Si: properties

E383ER308Si

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

75 GPa10.9 Msi
77 GPa11.2 Msi

Poisson's Ratio

0.3
0.29

Tensile Strength (Ultimate)

580 MPa84.1 ksi
600 MPa87 ksi

Yield Strength (0.2% offset)

390 MPa56.6 ksi
400 MPa58 ksi

Elongation at Break

35%
38%

Reduction in Area

45%
55%

Compressive Strength

395 MPa57.3 ksi
400 MPa58 ksi

Shear Strength

380 MPa55.1 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

230 MPa33.4 ksi
240 MPa34.8 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

185 HB
175 HB

Hardness, Rockwell B

90 HRB
88 HRB

Hardness, Vickers

195 HV
185 HV

Same in both: Elastic (Young's) Modulus 195 GPa28.3 Msi · Bulk Modulus 160 GPa23.2 Msi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,355°C2,471 °F
1,400°C2,552 °F

Liquidus Temperature

1,400°C2,552 °F
1,450°C2,642 °F

Thermal

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

Thermal Conductivity

11.5 W/m·K6.6 BTU/hr·ft·°F
15 W/m·K8.7 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
500 J/kg·K0.12 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

14.5 µm/m·K8.1 µin/in·°F
16.5 µm/m·K9.2 µin/in·°F

Latent Heat of Fusion

275 J/g118 BTU/lb
270 J/g116 BTU/lb

Max Service Temperature (continuous)

500°C932 °F
760°C1,400 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.7 % IACS
2.4 % IACS

Electrical Resistivity

1×10⁻⁶ Ω·m39.4 µΩ·in
7.2×10⁻⁷ Ω·m28.3 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.1 V
-0.08 V

Corrosion Resistance

86 / 100
68 / 100

Manufacturability

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

Machinability

25 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

28%
45%

Weldability

70 / 100
95 / 100

Formability (cold)

55 / 100
60 / 100

Polishability

65 / 100
70 / 100

Brazeability / Solderability

—
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

82 MJ/kg35,254 BTU/lb
55 MJ/kg23,646 BTU/lb

Embodied Carbon (primary production)

6.5 kg CO₂/kg
5.5 kg CO₂/kg

Embodied Water

180 L/kg21.6 gal/lb
200 L/kg24 gal/lb

Typical Recycled Content

40%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

73 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

24.4 MN·m/kg
24.5 MN·m/kg

Modulus of Resilience

390 kJ/m³
410 kJ/m³

Thermal Diffusivity

3.1 mm²/s
3.8 mm²/s

Thermal Shock Resistance Index

2
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 scaleER308SiE383

Manufacturing and finishing

CapabilityE383ER308Si
Default condition——
Relative cost$$$$ High$$$ 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.

E383 vs ER308Si — frequently asked

What is the difference between E383 and ER308Si?

Stainless Steel E383 and ER308Si are both stainless steel grades. Both yield at about 390 MPa — strength does not separate them. E383 is harder — 185 HB against 175 HB for ER308Si — which matters for wear surfaces and threads.

Which is cheaper, E383 or ER308Si?

ER308Si is the lower-cost material: it sits in the premium tier ($$$) while E383 is high ($$$$). 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, E383 or ER308Si?

ER308Si. Its machinability rates fair (40/100) against poor (25/100) for E383; for welding the order is ER308Si first (excellent, 95/100) then E383 (very good, 70/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in E383 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.