Stainless Steel 15-5 PH vs PH 13-8 Mo
Stainless Steel · grade comparison
Stainless Steel 15-5 PH and PH 13-8 Mo are both stainless steel grades, both high strength ss. Both yield at about 795 MPa — strength does not separate them. 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), 15-5 PH welds better (very good vs good), and PH 13-8 Mo sits in a lower cost tier (premium, $$$) than 15-5 PH (specialty, $$$$$).
15-5 PHChoose it when the part is machined in volume, or when it will be welded.
PH 13-8 MoChoose it when cost is the deciding factor.
15-5 PH vs PH 13-8 Mo: 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)
Reduction in Area
Compressive Strength
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elongation at Break 14% · Shear Strength 640 MPa92.8 ksi · Fatigue Strength (Endurance Limit) 480 MPa69.6 ksi · Hardness, Rockwell C 33 HRC
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)
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
Same in both: 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 | 15-5 PH | PH 13-8 Mo |
|---|---|---|
| 3D printing | 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 |
| 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.
15-5 PH vs PH 13-8 Mo — frequently asked
What is the difference between 15-5 PH and PH 13-8 Mo?
Stainless Steel 15-5 PH and PH 13-8 Mo are both stainless steel grades, both high strength ss. Both yield at about 795 MPa — strength does not separate them. 15-5 PH conducts heat better (17.9 W/m·K vs 14 W/m·K).
Which is cheaper, 15-5 PH or PH 13-8 Mo?
PH 13-8 Mo 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.
Which is easier to machine, 15-5 PH or PH 13-8 Mo?
15-5 PH. Its machinability rates fair (42/100) against poor (32/100) for PH 13-8 Mo; for welding the order is 15-5 PH first (very good, 70/100) then PH 13-8 Mo (good, 60/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15-5 PH and PH 13-8 Mo 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.