Stainless Steel 17-7 PH vs PH 13-8 Mo
Stainless Steel · grade comparison
Stainless Steel 17-7 PH and PH 13-8 Mo are both stainless steel grades, both high strength ss. PH 13-8 Mo is the stronger of the two: yield strength 800 MPa (116 ksi) against 276 MPa (40 ksi) for 17-7 PH, about 190% more; tensile strength follows at 1,000 MPa (145 ksi) vs 896 MPa (130 ksi). In exchange, 17-7 PH is the more ductile: elongation 35% versus 14% for PH 13-8 Mo, and PH 13-8 Mo is harder (320 HB vs 175 HB). 17-7 PH conducts heat better (16.4 W/m·K vs 14 W/m·K). On the shop floor, PH 13-8 Mo sits in a lower cost tier (premium, $$$) than 17-7 PH (specialty, $$$$$).
17-7 PHChoose it when the part is bent, formed or impact-loaded.
PH 13-8 MoChoose it when strength drives the design, or when cost is the deciding factor.
17-7 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Compressive Strength
Hardness, Rockwell C
Same in both: Poisson's Ratio 0.28
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
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Min Service Temperature
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°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 Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Same in both: Machinability 32 / 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
Same in both: Thermal Shock Resistance Index 7
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 | 17-7 PH | PH 13-8 Mo |
|---|---|---|
| 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 and Sheet metal. Both take the same 32 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, CrN, DLC, Electroless Nickel (EN), Electropolishing and 20 more.
17-7 PH vs PH 13-8 Mo — frequently asked
Is PH 13-8 Mo stronger than 17-7 PH?
Yes. PH 13-8 Mo has a typical yield strength of 800 MPa (116 ksi) against 276 MPa (40 ksi) for 17-7 PH — about 190% more. Tensile strength is 1,000 MPa (145 ksi) vs 896 MPa (130 ksi).
Which is cheaper, 17-7 PH or PH 13-8 Mo?
PH 13-8 Mo is the lower-cost material: it sits in the premium tier ($$$) while 17-7 PH is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, 17-7 PH or PH 13-8 Mo?
PH 13-8 Mo. Its weldability rates good (60/100) against good (55/100) for 17-7 PH.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 17-7 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.