Stainless Steel 17-4 PH vs Steel 4140
Cross-family material comparison
Stainless Steel 17-4 PH is a stainless steel grade and Steel 4140 is a steel grade — different families, so density, stiffness and cost move together with strength. 17-4 PH is the stronger of the two: yield strength 760 MPa (110 ksi) against 480 MPa (69.6 ksi) for 4140, about 58% more; tensile strength follows at 1,030 MPa (149 ksi) vs 690 MPa (100 ksi). In exchange, 4140 is the more ductile: elongation 22% versus 12% for 17-4 PH, and 17-4 PH is harder (311 HB vs 210 HB). 4140 runs hotter in service (425°C vs 200°C continuous) and 4140 conducts heat better (42.6 W/m·K vs 16.3 W/m·K). On the shop floor, 4140 machines more easily (good vs fair), 17-4 PH welds better (very good vs fair), and 4140 sits in a lower cost tier (standard, $$) than 17-4 PH (premium, $$$).
17-4 PHChoose it when strength drives the design, or when it will be welded.
4140Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
17-4 PH vs 4140: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all grades of the two families 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 grades of the two families 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
Shear Modulus
Bulk Modulus
Poisson's Ratio
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 C
Hardness, Vickers
Hardness, Rockwell B
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)
Castability
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 grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 17-4 PH | 4140 |
|---|---|---|
| 3D printing | Yes | — |
| Default condition | Condition A | HR |
| Relative cost | $$$ Premium | $$ Standard |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
| Copper Plating | — | Yes |
| E-Coating | — | Yes |
| Electropolished (Metal AM) | Yes | — |
| Electropolishing | Yes | — |
| Hot-Dip Galvanizing | — | Yes |
| Manganese Phosphate | — | Yes |
| Passivated (Metal AM) | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
| Pickling | Yes | — |
| Plated (Metal AM) | Yes | — |
| Tin Plating | — | Yes |
| Zinc Phosphate | — | Yes |
| Zinc Plating | — | Yes |
| Zinc-Flake (Dip-Spin) Coating | — | Yes |
| Zinc-Nickel Plating | — | Yes |
Both are offered for CNC machining, Sheet metal and Casting & forging. They share 29 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Epoxy Coating and 17 more.
17-4 PH vs 4140 — frequently asked
Is 17-4 PH stronger than 4140?
Yes. 17-4 PH has a typical yield strength of 760 MPa (110 ksi) against 480 MPa (69.6 ksi) for 4140 — about 58% more. Tensile strength is 1,030 MPa (149 ksi) vs 690 MPa (100 ksi).
Which is cheaper, 17-4 PH or 4140?
4140 is the lower-cost material: it sits in the standard tier ($$) while 17-4 PH is premium ($$$). 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, 17-4 PH or 4140?
4140. Its machinability rates good (60/100) against fair (45/100) for 17-4 PH; for welding the order is 17-4 PH first (very good, 70/100) then 4140 (fair, 40/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 17-4 PH 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.