Stainless Steel 17-4 PH vs AM-355
Stainless Steel · grade comparison
Stainless Steel 17-4 PH and AM-355 are both stainless steel grades. AM-355 is the stronger of the two: yield strength 1,070 MPa (155 ksi) against 760 MPa (110 ksi) for 17-4 PH, about 41% more; tensile strength follows at 1,275 MPa (185 ksi) vs 1,030 MPa (149 ksi). AM-355 is the more ductile: elongation 17% versus 12% for 17-4 PH, and AM-355 is harder (375 HB vs 311 HB). AM-355 runs hotter in service (425°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 sits in a lower cost tier (premium, $$$) than AM-355 (high, $$$$).
17-4 PHChoose it when the part is machined in volume, or when it will be welded.
AM-355Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
17-4 PH vs AM-355: 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)
Elongation at Break
Reduction in Area
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
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
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 · Latent Heat of Fusion 270 J/g116 BTU/lb
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).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.15 V
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
Polishability
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 | 17-4 PH | AM-355 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| 3D printing | Yes | — |
| Casting & forging | Yes | — |
| Default condition | Condition A | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| Black Oxide | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| Cerakote | Yes | — |
| Chrome Plating | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| Electropolished (Metal AM) | Yes | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| Nickel Plating | Yes | — |
| PTFE Coating | Yes | — |
| Painting | Yes | — |
They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.
17-4 PH vs AM-355 — frequently asked
Is AM-355 stronger than 17-4 PH?
Yes. AM-355 has a typical yield strength of 1,070 MPa (155 ksi) against 760 MPa (110 ksi) for 17-4 PH — about 41% more. Tensile strength is 1,275 MPa (185 ksi) vs 1,030 MPa (149 ksi).
Which is cheaper, 17-4 PH or AM-355?
17-4 PH is the lower-cost material: it sits in the premium tier ($$$) while AM-355 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 AM-355?
17-4 PH. Its machinability rates fair (45/100) against poor (22/100) for AM-355; for welding the order is 17-4 PH first (very good, 70/100) then AM-355 (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 17-4 PH and AM-355 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.