Stainless Steel 15-5 PH vs 17-4 PH
Stainless Steel · grade comparison
Stainless Steel 15-5 PH and 17-4 PH are both stainless steel grades, both high strength ss. Both yield at about 795 MPa — strength does not separate them. 15-5 PH is the more ductile: elongation 14% versus 12% for 17-4 PH. 15-5 PH runs hotter in service (300°C vs 200°C continuous). On the shop floor, 17-4 PH sits in a lower cost tier (premium, $$$) than 15-5 PH (specialty, $$$$$).
15-5 PHChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
17-4 PHChoose it when cost is the deciding factor.
15-5 PH vs 17-4 PH: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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.
Bulk Modulus
Poisson's Ratio
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)
Same in both: Elastic (Young's) Modulus 196 GPa28.4 Msi · Shear Modulus 77 GPa11.2 Msi · Tensile Strength (Ultimate) 1,030 MPa149 ksi · Hardness, Brinell 311 HB · Hardness, Rockwell C 33 HRC · Hardness, Vickers 330 HV
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Same in both: Liquidus Temperature 1,440°C2,624 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Max Service Temperature (continuous)
Same in both: Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -73°C-99 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
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 %)
Formability (cold)
Castability
Polishability
Same in both: Weldability 70 / 100 · Brazeability / Solderability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb
Common Calculations
Ratios derived from the values above.
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Strength (UTS / density) 132 kN·m/kg
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 15-5 PH | 17-4 PH |
|---|---|---|
| Casting & forging | — | Yes |
| Default condition | Condition A | Condition A |
| Relative cost | $$$$$ Specialty | $$$ Premium |
| 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, Sheet metal and 3D printing. Both take the same 35 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolished (Metal AM) and 23 more.
15-5 PH vs 17-4 PH — frequently asked
What is the difference between 15-5 PH and 17-4 PH?
Stainless Steel 15-5 PH and 17-4 PH are both stainless steel grades, both high strength ss. Both yield at about 795 MPa — strength does not separate them. 15-5 PH is the more ductile: elongation 14% versus 12% for 17-4 PH.
Which is cheaper, 15-5 PH or 17-4 PH?
17-4 PH is the lower-cost material: it sits in the premium tier ($$$) while 15-5 PH is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose 15-5 PH over 17-4 PH?
Pick 15-5 PH when the part is bent, formed or impact-loaded, or when the part sees heat. Pick 17-4 PH when cost is the deciding factor.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15-5 PH and 17-4 PH 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.