Stainless Steel 13-8 PH vs 15-5 PH
Stainless Steel · grade comparison
Stainless Steel 13-8 PH and 15-5 PH are both stainless steel grades, both high strength ss. Both yield at about 827 MPa — strength does not separate them. 13-8 PH runs hotter in service (425°C vs 300°C continuous) and 15-5 PH conducts heat better (17.9 W/m·K vs 14 W/m·K). On the shop floor, 15-5 PH machines more easily (fair vs poor) and 15-5 PH forms better (fair vs poor).
13-8 PHChoose it when the part sees heat.
15-5 PHChoose it when the part is machined in volume.
13-8 PH vs 15-5 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Same in both: Reduction in Area 55% · Fatigue Strength (Endurance Limit) 480 MPa69.6 ksi · Hardness, Brinell 311 HB · Hardness, Rockwell C 33 HRC · Hardness, Vickers 330 HV
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,440°C2,624 °F
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)
Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -73°C-99 °F
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
Same in both: Brazeability / Solderability 45 / 100 · Polishability 80 / 100
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 stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | 13-8 PH | 15-5 PH |
|---|---|---|
| 3D printing | — | Yes |
| Default condition | Condition A | Condition A |
| Relative cost | $$$$$ Specialty | $$$$$ Specialty |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
| Electropolished (Metal AM) | — | Yes |
| Passivated (Metal AM) | — | Yes |
| Plated (Metal AM) | — | Yes |
Both are offered for CNC machining and Sheet metal. They share 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.
13-8 PH vs 15-5 PH — frequently asked
What is the difference between 13-8 PH and 15-5 PH?
Stainless Steel 13-8 PH and 15-5 PH are both stainless steel grades, both high strength ss. Both yield at about 827 MPa — strength does not separate them. 13-8 PH runs hotter in service (425°C vs 300°C continuous) and 15-5 PH conducts heat better (17.9 W/m·K vs 14 W/m·K).
Which is cheaper, 13-8 PH or 15-5 PH?
Both sit in the same relative cost tier ($$$$$, specialty); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 13-8 PH or 15-5 PH?
15-5 PH. Its machinability rates fair (42/100) against poor (32/100) for 13-8 PH; for welding the order is 15-5 PH first (very good, 70/100) then 13-8 PH (good, 62/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 13-8 PH and 15-5 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.