Steel 8620 vs S7
Steel · grade comparison
Steel 8620 and S7 are both steel grades. S7 is the stronger of the two: yield strength 530 MPa (76.9 ksi) against 385 MPa (55.8 ksi) for 8620, about 38% more; tensile strength follows at 830 MPa (120 ksi) vs 635 MPa (92.1 ksi). In exchange, 8620 is the more ductile: elongation 28% versus 18% for S7, and S7 is harder (200 HB vs 183 HB). S7 runs hotter in service (500°C vs 400°C continuous) and 8620 conducts heat better (46.6 W/m·K vs 26 W/m·K). On the shop floor, 8620 machines more easily (good vs fair), 8620 welds better (good vs poor), and 8620 sits in a lower cost tier (standard, $$) than S7 (specialty, $$$$$).
8620Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
S7Choose it when strength drives the design, or when the part sees heat.
8620 vs S7: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Compressive Strength
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 8620 | S7 |
|---|---|---|
| Sheet metal | Yes | — |
| Default condition | HR | Annealed |
| Relative cost | $$ Standard | $$$$$ Specialty |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
8620 vs S7 — frequently asked
Is S7 stronger than 8620?
Yes. S7 has a typical yield strength of 530 MPa (76.9 ksi) against 385 MPa (55.8 ksi) for 8620 — about 38% more. Tensile strength is 830 MPa (120 ksi) vs 635 MPa (92.1 ksi).
Which is cheaper, 8620 or S7?
8620 is the lower-cost material: it sits in the standard tier ($$) while S7 is specialty ($$$$$). 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, 8620 or S7?
8620. Its machinability rates good (62/100) against fair (50/100) for S7; for welding the order is 8620 first (good, 60/100) then S7 (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 8620 and S7 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.