Steel 4118 vs 4720
Steel · grade comparison
Steel 4118 and 4720 are both steel grades. 4720 is the stronger of the two: yield strength 430 MPa (62.4 ksi) against 350 MPa (50.8 ksi) for 4118, about 23% more; tensile strength follows at 640 MPa (92.8 ksi) vs 530 MPa (76.9 ksi). In exchange, 4118 is the more ductile: elongation 26% versus 23% for 4720, and 4720 is harder (200 HB vs 149 HB). 4118 runs hotter in service (400°C vs 350°C continuous).
4118Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4720Choose it when strength drives the design.
4118 vs 4720: 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Compressive Strength
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 55%
Physical
Density and transition temperatures.
Liquidus Temperature
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Same in both: Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 65%
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 26.1 MN·m/kg
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 | 4118 | 4720 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.
4118 vs 4720 — frequently asked
Is 4720 stronger than 4118?
Yes. 4720 has a typical yield strength of 430 MPa (62.4 ksi) against 350 MPa (50.8 ksi) for 4118 — about 23% more. Tensile strength is 640 MPa (92.8 ksi) vs 530 MPa (76.9 ksi).
Which is cheaper, 4118 or 4720?
Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, 4118 or 4720?
4118. Its weldability rates good (60/100) against good (55/100) for 4720.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4118 and 4720 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.