Steel 4130 vs S7
Steel · grade comparison
Steel 4130 and S7 are both steel grades. S7 is the stronger of the two: yield strength 530 MPa (76.9 ksi) against 440 MPa (63.8 ksi) for 4130, about 20% more; tensile strength follows at 830 MPa (120 ksi) vs 700 MPa (102 ksi). In exchange, 4130 is the more ductile: elongation 22% versus 18% for S7, and 4130 is harder (228 HV vs 210 HV). S7 runs hotter in service (500°C vs 400°C continuous) and 4130 conducts heat better (42.7 W/m·K vs 26 W/m·K). On the shop floor, 4130 welds better (good vs poor) and 4130 sits in a lower cost tier (standard, $$) than S7 (specialty, $$$$$).
4130Choose it when the part is bent, formed or impact-loaded, or when it will be welded.
S7Choose it when strength drives the design, or when the part sees heat.
4130 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Hardness, Rockwell C
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)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
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 | 4130 | S7 |
|---|---|---|
| Sheet metal | Yes | — |
| Default condition | HR | Annealed |
| Relative cost | $$ Standard | $$$$$ Specialty |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
4130 vs S7 — frequently asked
Is S7 stronger than 4130?
Yes. S7 has a typical yield strength of 530 MPa (76.9 ksi) against 440 MPa (63.8 ksi) for 4130 — about 20% more. Tensile strength is 830 MPa (120 ksi) vs 700 MPa (102 ksi).
Which is cheaper, 4130 or S7?
4130 is the lower-cost material: it sits in the standard tier ($$) 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, 4130 or S7?
4130. Its machinability rates good (55/100) against fair (50/100) for S7; for welding the order is 4130 first (good, 65/100) then S7 (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4130 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.