Stainless Steel 17-4 PH vs 420J1
Stainless Steel · grade comparison
Stainless Steel 17-4 PH and 420J1 are both stainless steel grades, both high strength ss. 17-4 PH is the stronger of the two: yield strength 760 MPa (110 ksi) against 440 MPa (63.8 ksi) for 420J1, about 73% more; tensile strength follows at 1,030 MPa (149 ksi) vs 700 MPa (102 ksi). In exchange, 420J1 is the more ductile: elongation 22% versus 12% for 17-4 PH, and 17-4 PH is harder (311 HB vs 195 HB). 420J1 runs hotter in service (600°C vs 200°C continuous) and 420J1 conducts heat better (30 W/m·K vs 16.3 W/m·K). On the shop floor, 17-4 PH welds better (very good vs fair).
17-4 PHChoose it when strength drives the design, or when it will be welded.
420J1Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
17-4 PH vs 420J1: 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
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
Hardness, Rockwell B
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 270 J/g116 BTU/lb
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
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 | 420J1 |
|---|---|---|
| Sheet metal | Yes | — |
| 3D printing | Yes | — |
| Casting & forging | Yes | — |
| Default condition | Condition A | Annealed |
| Relative cost | $$$ Premium | $$$ 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. 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.
17-4 PH vs 420J1 — frequently asked
Is 17-4 PH stronger than 420J1?
Yes. 17-4 PH has a typical yield strength of 760 MPa (110 ksi) against 440 MPa (63.8 ksi) for 420J1 — about 73% more. Tensile strength is 1,030 MPa (149 ksi) vs 700 MPa (102 ksi).
Which is cheaper, 17-4 PH or 420J1?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, 17-4 PH or 420J1?
17-4 PH. Its weldability rates very good (70/100) against fair (35/100) for 420J1.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 17-4 PH and 420J1 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.