Steel 4068 vs 4140
Steel · grade comparison
Steel 4068 and 4140 are both steel grades. 4140 is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 420 MPa (60.9 ksi) for 4068, about 14% more. 4140 runs hotter in service (425°C vs 200°C continuous). On the shop floor, 4140 machines more easily (good vs fair), 4140 welds better (fair vs not recommended), and 4140 forms better (fair vs poor).
4068Choose it when cost is the deciding factor.
4140Choose it when strength drives the design, or when the part sees heat.
4068 vs 4140: 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)
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Fracture Toughness (K_IC)
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 · Elongation at Break 22% · Hardness, Rockwell B 94 HRB
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 7.85 g/cm³0.28 lb/in³
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)
Min Service Temperature
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V
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 Water
Same in both: Embodied Carbon (primary production) 2.2 kg CO₂/kg · Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: Specific Stiffness (E / density) 26.1 MN·m/kg · Thermal Shock Resistance Index 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.
Manufacturing and finishing
| Capability | 4068 | 4140 |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Casting & forging | — | Yes |
| Default condition | — | HR |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | — | 0.8 mm |
| Best machined surface | — | Ra 1.6 µm |
| AlCrN | — | Yes |
| AlTiN | — | Yes |
| Black Oxide | — | Yes |
| CVD Al2O3 | — | Yes |
| CVD TiCN | — | Yes |
| CVD TiN | — | Yes |
| Cerakote | — | Yes |
| Chrome Plating | — | Yes |
| CrN | — | Yes |
| DLC | — | Yes |
| E-Coating | — | Yes |
| HVOF Coating | — | Yes |
| Hot-Dip Galvanizing | — | Yes |
| MoS2 | — | Yes |
| Multilayer CVD | — | Yes |
| Nickel Plating | — | Yes |
| PTFE Coating | — | Yes |
| Painting | — | Yes |
They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.
4068 vs 4140 — frequently asked
Is 4140 stronger than 4068?
Yes. 4140 has a typical yield strength of 480 MPa (69.6 ksi) against 420 MPa (60.9 ksi) for 4068 — about 14% more. Tensile strength is 690 MPa (100 ksi) vs 700 MPa (102 ksi).
Which is cheaper, 4068 or 4140?
4068 is the lower-cost material: it sits in the budget tier ($) while 4140 is standard ($$). 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, 4068 or 4140?
4140. Its machinability rates good (60/100) against fair (45/100) for 4068; for welding the order is 4140 first (fair, 40/100) then 4068 (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4068 and 4140 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.