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Steel 316LSi vs 8620

Steel · grade comparison

Steel 316LSi and 8620 are both steel grades. 8620 is the stronger of the two: tensile strength 635 MPa (92.1 ksi) against 580 MPa (84.1 ksi) for 316LSi, about 9% more. In exchange, 316LSi is the more ductile: elongation 40% versus 28% for 8620. 316LSi runs hotter in service (450°C vs 400°C continuous) and 8620 conducts heat better (46.6 W/m·K vs 15 W/m·K). On the shop floor, 8620 machines more easily (good vs fair), 316LSi welds better (excellent vs good), and 8620 sits in a lower cost tier (standard, $$) than 316LSi (premium, $$$).

316LSiChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

8620Choose it when strength drives the design, or when the part is machined in volume.

316LSi vs 8620: properties

316LSi8620

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

195 GPa28.3 Msi
205 GPa29.7 Msi

Shear Modulus

77 GPa11.2 Msi
80 GPa11.6 Msi

Bulk Modulus

166 GPa24.1 Msi
160 GPa23.2 Msi

Tensile Strength (Ultimate)

580 MPa84.1 ksi
635 MPa92.1 ksi

Yield Strength (0.2% offset)

400 MPa58 ksi
385 MPa55.8 ksi

Elongation at Break

40%
28%

Reduction in Area

55%
60%

Compressive Strength

410 MPa59.5 ksi
—

Shear Strength

380 MPa55.1 ksi
390 MPa56.6 ksi

Fatigue Strength (Endurance Limit)

230 MPa33.4 ksi
295 MPa42.8 ksi

Fracture Toughness (K_IC)

160 MPa·√m146 ksi·√in
85 MPa·√m77.4 ksi·√in

Charpy V-Notch Impact (RT)

100 J73.8 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

175 HB
183 HB

Hardness, Rockwell B

88 HRB
90 HRB

Hardness, Vickers

185 HV
—

Same in both: Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Density

7.98 g/cm³0.29 lb/in³
7.85 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,390°C2,534 °F
1,425°C2,597 °F

Liquidus Temperature

1,440°C2,624 °F
1,505°C2,741 °F

Thermal

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

Thermal Conductivity

15 W/m·K8.7 BTU/hr·ft·°F
46.6 W/m·K26.9 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

16 µm/m·K8.9 µin/in·°F
11.6 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

450°C842 °F
400°C752 °F

Min Service Temperature

-196°C-321 °F
-40°C-40 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

2.3 % IACS
8 % IACS

Electrical Resistivity

7.5×10⁻⁷ Ω·m29.5 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.08 V
-0.6 V

Corrosion Resistance

74 / 100
11 / 100

Manufacturability

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

Machinability

40 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

36%
65%

Weldability

92 / 100
60 / 100

Formability (cold)

78 / 100
55 / 100

Castability

60 / 100
—

Same in both: Brazeability / Solderability 65 / 100 · Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

56 MJ/kg24,076 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

5.2 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

110 L/kg13.2 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

70%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

73 kN·m/kg
81 kN·m/kg

Specific Stiffness (E / density)

24.4 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

410 kJ/m³
362 kJ/m³

Thermal Diffusivity

3.8 mm²/s
12.5 mm²/s

Thermal Shock Resistance Index

3
12

Strength versus weight

Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale8620316LSi

Manufacturing and finishing

Capability316LSi8620
CNC machining—Yes
Sheet metal—Yes
Default condition—HR
Relative cost$$$ Premium$$ Standard
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

316LSi vs 8620 — frequently asked

Is 8620 stronger than 316LSi?

Yes. 8620 has a typical tensile strength of 635 MPa (92.1 ksi) against 580 MPa (84.1 ksi) for 316LSi — about 9% more.

Which is cheaper, 316LSi or 8620?

8620 is the lower-cost material: it sits in the standard tier ($$) while 316LSi is premium ($$$). 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, 316LSi or 8620?

8620. Its machinability rates good (62/100) against fair (40/100) for 316LSi; for welding the order is 316LSi first (excellent, 92/100) then 8620 (good, 60/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 316LSi and 8620 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.