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Stainless Steel E308Mo vs ER308

Stainless Steel · grade comparison

Stainless Steel E308Mo and ER308 are both stainless steel grades. Both yield at about 420 MPa — strength does not separate them. ER308 runs hotter in service (760°C vs 650°C continuous).

ER308Choose it when the part sees heat.

E308Mo vs ER308: properties

E308MoER308

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

193 GPa28 Msi
195 GPa28.3 Msi

Bulk Modulus

160 GPa23.2 Msi
145 GPa21 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

590 MPa85.6 ksi
600 MPa87 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
400 MPa58 ksi

Elongation at Break

38%
40%

Compressive Strength

425 MPa61.6 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

120 MPa·√m109 ksi·√in
150 MPa·√m137 ksi·√in

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

180 HB
185 HB

Hardness, Rockwell B

89 HRB
90 HRB

Hardness, Vickers

190 HV
195 HV

Same in both: Shear Modulus 77 GPa11.2 Msi · Reduction in Area 55% · Shear Strength 400 MPa58 ksi · Fatigue Strength (Endurance Limit) 240 MPa34.8 ksi

Physical

Density and transition temperatures.

Liquidus Temperature

1,445°C2,633 °F
1,450°C2,642 °F

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

Thermal

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

Thermal Conductivity

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

Thermal Expansion (CTE, 20–100 °C)

16.5 µm/m·K9.2 µin/in·°F
16.9 µm/m·K9.4 µin/in·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

650°C1,202 °F
760°C1,400 °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

2.3 % IACS
2.4 % IACS

Electrical Resistivity

7.5×10⁻⁷ Ω·m29.5 µΩ·in
7.4×10⁻⁷ Ω·m29.1 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.05 V
-0.08 V

Corrosion Resistance

66 / 100
65 / 100

Manufacturability

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

Machinability Rating (AISI 1212 = 100 %)

40%
45%

Weldability

90 / 100
95 / 100

Formability (cold)

60 / 100
55 / 100

Brazeability / Solderability

55 / 100
60 / 100

Polishability

65 / 100
70 / 100

Same in both: Machinability 38 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
57 MJ/kg24,506 BTU/lb

Embodied Carbon (primary production)

5.5 kg CO₂/kg
5 kg CO₂/kg

Typical Recycled Content

60%
45%

Same in both: Embodied Water 130 L/kg15.6 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

75 kN·m/kg
76 kN·m/kg

Specific Stiffness (E / density)

24.4 MN·m/kg
24.7 MN·m/kg

Modulus of Resilience

457 kJ/m³
410 kJ/m³

Thermal Diffusivity

3.8 mm²/s
3.9 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 scaleER308E308Mo

Manufacturing and finishing

CapabilityE308MoER308
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.

E308Mo vs ER308 — frequently asked

What is the difference between E308Mo and ER308?

Stainless Steel E308Mo and ER308 are both stainless steel grades. Both yield at about 420 MPa — strength does not separate them. ER308 runs hotter in service (760°C vs 650°C continuous).

Which is cheaper, E308Mo or ER308?

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, E308Mo or ER308?

ER308. Its weldability rates excellent (95/100) against excellent (90/100) for E308Mo.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E308Mo and ER308 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.