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Stainless Steel E630 vs ER308

Stainless Steel · grade comparison

Stainless Steel E630 and ER308 are both stainless steel grades. E630 is the stronger of the two: yield strength 760 MPa (110 ksi) against 400 MPa (58 ksi) for ER308, about 90% more; tensile strength follows at 1,010 MPa (146 ksi) vs 600 MPa (87 ksi). In exchange, ER308 is the more ductile: elongation 40% versus 10% for E630, and E630 is harder (311 HB vs 185 HB). ER308 runs hotter in service (760°C vs 300°C continuous) and E630 conducts heat better (17.8 W/m·K vs 15.5 W/m·K). On the shop floor, ER308 welds better (excellent vs good) and ER308 sits in a lower cost tier (premium, $$$) than E630 (high, $$$$).

E630Choose it when strength drives the design.

ER308Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

E630 vs ER308: properties

E630ER308

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

196 GPa28.4 Msi
195 GPa28.3 Msi

Bulk Modulus

142 GPa20.6 Msi
145 GPa21 Msi

Poisson's Ratio

0.27
0.3

Tensile Strength (Ultimate)

1,010 MPa146 ksi
600 MPa87 ksi

Yield Strength (0.2% offset)

760 MPa110 ksi
400 MPa58 ksi

Elongation at Break

10%
40%

Reduction in Area

35%
55%

Compressive Strength

790 MPa115 ksi
400 MPa58 ksi

Shear Strength

640 MPa92.8 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

420 MPa60.9 ksi
240 MPa34.8 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
150 MPa·√m137 ksi·√in

Charpy V-Notch Impact (RT)

22 J16.2 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

311 HB
185 HB

Hardness, Rockwell C

33 HRC
—

Hardness, Vickers

330 HV
195 HV

Hardness, Rockwell B

—
90 HRB

Same in both: Shear Modulus 77 GPa11.2 Msi

Physical

Density and transition temperatures.

Density

7.78 g/cm³0.28 lb/in³
7.9 g/cm³0.29 lb/in³

Melting Point (Solidus)

1,404°C2,559 °F
1,400°C2,552 °F

Liquidus Temperature

1,440°C2,624 °F
1,450°C2,642 °F

Thermal

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

Thermal Conductivity

17.8 W/m·K10.3 BTU/hr·ft·°F
15.5 W/m·K9 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)

10.8 µm/m·K6 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)

300°C572 °F
760°C1,400 °F

Min Service Temperature

-50°C-58 °F
-196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.2 % IACS
2.4 % IACS

Electrical Resistivity

8×10⁻⁷ Ω·m31.5 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)

-0.28 V
-0.08 V

Corrosion Resistance

52 / 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

65 / 100
95 / 100

Formability (cold)

25 / 100
55 / 100

Brazeability / Solderability

45 / 100
60 / 100

Same in both: Machinability 38 / 100 · Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

62 MJ/kg26,655 BTU/lb
57 MJ/kg24,506 BTU/lb

Embodied Carbon (primary production)

4.6 kg CO₂/kg
5 kg CO₂/kg

Typical Recycled Content

55%
45%

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

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

130 kN·m/kg
76 kN·m/kg

Specific Stiffness (E / density)

25.2 MN·m/kg
24.7 MN·m/kg

Modulus of Resilience

1,473 kJ/m³
410 kJ/m³

Thermal Diffusivity

5 mm²/s
3.9 mm²/s

Thermal Shock Resistance Index

8
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 scaleER308E630

Manufacturing and finishing

CapabilityE630ER308
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.

E630 vs ER308 — frequently asked

Is E630 stronger than ER308?

Yes. E630 has a typical yield strength of 760 MPa (110 ksi) against 400 MPa (58 ksi) for ER308 — about 90% more. Tensile strength is 1,010 MPa (146 ksi) vs 600 MPa (87 ksi).

Which is cheaper, E630 or ER308?

ER308 is the lower-cost material: it sits in the premium tier ($$$) while E630 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which welds better, E630 or ER308?

ER308. Its weldability rates excellent (95/100) against good (65/100) for E630.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E630 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.