Stainless Steel 17-4 PH vs XM-9
Stainless Steel · grade comparison
Stainless Steel 17-4 PH and XM-9 are both stainless steel grades. XM-9 is the stronger of the two: yield strength 1,240 MPa (180 ksi) against 760 MPa (110 ksi) for 17-4 PH, about 63% more; tensile strength follows at 1,345 MPa (195 ksi) vs 1,030 MPa (149 ksi). XM-9 is harder — 400 HB against 311 HB for 17-4 PH — which matters for wear surfaces and threads. XM-9 runs hotter in service (315°C vs 200°C continuous). On the shop floor, 17-4 PH machines more easily (fair vs poor), 17-4 PH welds better (very good vs fair), and 17-4 PH forms better (fair vs poor).
17-4 PHChoose it when the part is machined in volume, or when it will be welded.
XM-9Choose it when strength drives the design, or when surface hardness matters.
17-4 PH vs XM-9: 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 77 GPa11.2 Msi · Elongation at Break 12% · Reduction in Area 45%
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Thermal Conductivity 16.3 W/m·K9.4 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 2.2 % IACS
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 75 / 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 Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Shock Resistance Index
Same in both: Thermal Diffusivity 4.6 mm²/s
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 | 17-4 PH | XM-9 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| 3D printing | Yes | — |
| Casting & forging | Yes | — |
| Default condition | Condition A | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolished (Metal AM) | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
17-4 PH vs XM-9 — frequently asked
Is XM-9 stronger than 17-4 PH?
Yes. XM-9 has a typical yield strength of 1,240 MPa (180 ksi) against 760 MPa (110 ksi) for 17-4 PH — about 63% more. Tensile strength is 1,345 MPa (195 ksi) vs 1,030 MPa (149 ksi).
Which is cheaper, 17-4 PH or XM-9?
17-4 PH is the lower-cost material: it sits in the premium tier ($$$) while XM-9 is high ($$$$). 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 XM-9?
17-4 PH. Its machinability rates fair (45/100) against poor (25/100) for XM-9; for welding the order is 17-4 PH first (very good, 70/100) then XM-9 (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 17-4 PH and XM-9 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.