FabDigitFabDigit

Stainless Steel E318 vs ER308H

Stainless Steel · grade comparison

Stainless Steel E318 and ER308H are both stainless steel grades. Both yield at about 415 MPa — strength does not separate them. On the shop floor, ER308H forms better (good vs fair) and ER308H sits in a lower cost tier (premium, $$$) than E318 (high, $$$$).

ER308HChoose it when cost is the deciding factor.

E318 vs ER308H: properties

E318ER308H

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

190 GPa27.6 Msi
196 GPa28.4 Msi

Elongation at Break

35%
38%

Reduction in Area

45%
55%

Shear Strength

390 MPa56.6 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 ksi
230 MPa33.4 ksi

Fracture Toughness (K_IC)

120 MPa·√m109 ksi·√in
180 MPa·√m164 ksi·√in

Charpy V-Notch Impact (RT)

65 J47.9 ft·lbf
85 J62.7 ft·lbf

Hardness, Brinell

180 HB
175 HB

Hardness, Rockwell B

89 HRB
87 HRB

Hardness, Vickers

190 HV
185 HV

Same in both: Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Tensile Strength (Ultimate) 590 MPa85.6 ksi · Yield Strength (0.2% offset) 415 MPa60.2 ksi · Compressive Strength 420 MPa60.9 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,375°C2,507 °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

16 W/m·K9.2 BTU/hr·ft·°F
16.2 W/m·K9.4 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

16 µm/m·K8.9 µin/in·°F
16.5 µm/m·K9.2 µin/in·°F

Latent Heat of Fusion

280 J/g120 BTU/lb
285 J/g123 BTU/lb

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 · Max Service Temperature (continuous) 800°C1,472 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.2 % IACS
2.4 % IACS

Electrical Resistivity

7.8×10⁻⁷ Ω·m30.7 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
-0.05 V

Corrosion Resistance

72 / 100
58 / 100

Manufacturability

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

Machinability

30 / 100
38 / 100

Machinability Rating (AISI 1212 = 100 %)

33%
40%

Formability (cold)

45 / 100
55 / 100

Same in both: Weldability 88 / 100 · Brazeability / Solderability 60 / 100 · Polishability 65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

5 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

55%
60%

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)

74 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

23.9 MN·m/kg
24.8 MN·m/kg

Modulus of Resilience

453 kJ/m³
439 kJ/m³

Thermal Diffusivity

4 mm²/s
4.1 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 scaleER308HE318

Manufacturing and finishing

CapabilityE318ER308H
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.

E318 vs ER308H — frequently asked

What is the difference between E318 and ER308H?

Stainless Steel E318 and ER308H are both stainless steel grades. Both yield at about 415 MPa — strength does not separate them. On the shop floor, ER308H forms better (good vs fair) and ER308H sits in a lower cost tier (premium, $$$) than E318 (high, $$$$).

Which is cheaper, E318 or ER308H?

ER308H is the lower-cost material: it sits in the premium tier ($$$) while E318 is high ($$$$). 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, E318 or ER308H?

ER308H. Its machinability rates fair (38/100) against poor (30/100) for E318.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E318 and ER308H 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.