High Strength After H900
A standard H900 age pushes typical tensile strength to about 1340 MPa with yield around 1240 MPa, so thin sections can still carry serious load.
17-4 PH Stainless SteelDMLS Material
17-4 PH is a martensitic precipitation-hardening stainless steel that combines high strength and good corrosion resistance. The powder chemistry matches ASTM A564 (UNS S17400). To reach full hardness and repeatable mechanical properties, parts are typically solution annealed and then aged.
About 17-4 PH Stainless Steel
17-4 PH gets its name from its 17% chromium and 4% nickel balance. It is one of the alloys we reach for when a part needs stainless corrosion behavior but also has to age harden into the low-40s HRC range.
We treat it as a two-stage material. First we print the geometry, then we run controlled heat treatment to lock in the target condition. The heat-treatment decision matters as much as build orientation for final strength and ductility.
We produce it on our direct metal laser sintering systems and help choose an aging condition that matches your load case, corrosion environment, and post-machining needs.
Why Choose 17-4 PH?
We reach for 17-4 PH when a part needs more strength than 316L can give without leaving the stainless family for a tool steel.
Good Corrosion Resistance
17-4 PH resists many service environments better than tool and maraging steels while keeping far higher hardness and strength than 316L.
Adjustable Hardness by Aging
Moving from H900 to H1150 tunes hardness from roughly 42 HRC down toward 28 HRC, so we balance wear resistance against ductility to suit the part.
Familiar ASTM Chemistry
The powder chemistry aligns with ASTM A564 (UNS S17400), so teams already specifying wrought or cast 17-4 PH stay in a known material family.
Typical Applications
We print 17-4 PH for critical hardware that needs strength, corrosion resistance, and clear heat treatment traceability. Most requests tie back to aviation, defense, and medical programs.
Engineering Hardware
Load-bearing components that need both strength and corrosion resistance, including housings, fixture details, and structural machine elements.
Medical and Surgical Instruments
Often selected for reusable instrument hardware where cleanability and high strength matter. We review alloy condition and validation requirements for each program.
Aerospace and Defense Components
Rugged hardware for aircraft and defense systems where high static strength, predictable heat treatment response, and corrosion resistance are all required.
Fasteners and Shafts
High-strength threaded features, couplers, and shaft-like geometries that benefit from precipitation hardening and DMLS design freedom in one part.
If you are deciding between 17-4 PH, 316L, maraging steel, or Inconel, send us the part and the service conditions. We will recommend the alloy and aging condition that best fits the job.
Technical Specifications
These values come from the EOS IndustryLine 17-4PH data sheet for M 290 at 40 µm plus EOS published updates for the newer 40/80 µm heat-treated process set. We list orientation and heat-treatment condition explicitly because those choices move the numbers.
ASTM A564Chemistry per UNS S17400 limits
7.79 g/cm³Mean part density
0.030%Average porosity after heat treatment
Powder chemical composition (wt.-%)
| Element | Min. | Max. |
|---|---|---|
| Cr | 15.0 | 17.5 |
| Ni | 3.0 | 5.0 |
| Cu | 3.0 | 5.0 |
| Si | — | 1.0 |
| Mn | — | 1.0 |
| C | — | 0.07 |
| P | — | 0.04 |
| S | — | 0.03 |
| Nb + Ta | 0.15 | 0.45 |
| Fe | Balance | Balance |
Published process data
| System | Layer thickness | Build rate | Min. wall thickness | Inert gas |
|---|---|---|---|---|
| EOS M 290 | 40 µm | ~3.32 mm³/s | ~0.4 mm | Argon |
Physical data and process notes
| Property | Typical value | Note |
|---|---|---|
| Particle size distribution | ~15–65 µm | D50: 36–44 µm |
| Mean part density | 7.79 g/cm³ | Measured on M 290 40 µm samples |
| Average porosity after heat treatment | 0.030% | Microscopy-based average value |
| Typical shrinkage after heat treatment | ~0.2% | Use for compensation planning |
Mechanical properties, as built
| Orientation | Yield strength Rp0.2 [MPa] | Tensile strength Rm [MPa] | Elongation at break A [%] | Hardness [HRC] |
|---|---|---|---|---|
| Horizontal | 861 | 886 | 19.9 | 23.9 |
| Vertical | 861 | 924 | 20.1 | — |
Mechanical properties, vacuum H900
| Orientation | Yield strength Rp0.2 [MPa] | Tensile strength Rm [MPa] | Elongation at break A [%] | Hardness [HRC] |
|---|---|---|---|---|
| Horizontal | 1235 | 1336 | 14.0 | 42.1 |
| Vertical | 1251 | 1343 | 13.5 | 42.1 |
Mechanical properties, atmospheric heat treatment (argon preferred)
| Orientation | Yield strength Rp0.2 [MPa] | Tensile strength Rm [MPa] | Elongation at break A [%] |
|---|---|---|---|
| Horizontal | 1236 | 1340 | 13.5 |
| Vertical | 1243 | 1346 | 12.6 |
Typical hardness after heat treatment is about 42 HRC, with a practical floor around 40 HRC for this condition set.
Mechanical properties, newer 40/80 µm HT process set
| Orientation | Yield strength Rp0.2 [MPa] | Tensile strength Rm [MPa] | Elongation at break A [%] |
|---|---|---|---|
| Horizontal | ~1240 | ~1360 | 13–14 |
| Vertical | ~1240 | ~1360 | 13–14 |
Aging condition hardness guide
| Condition | Ageing cycle | Typical hardness [HRC] |
|---|---|---|
| H900 | 480 °C for 1 h | 42 |
| H925 | 495 °C for 4 h | 38 |
| H1025 | 550 °C for 4 h | 36 |
| H1075 | 580 °C for 4 h | 34 |
| H1100 | 595 °C for 4 h | 32 |
| H1150 | 620 °C for 4 h | 28 |
Coefficient of thermal expansion after atmospheric HT
| Temperature range | CTE |
|---|---|
| 25–100 °C | 10.4 ×10⁻⁶/K |
| 25–200 °C | 11.0 ×10⁻⁶/K |
| 25–300 °C | 11.4 ×10⁻⁶/K |
| 25–400 °C | 11.8 ×10⁻⁶/K |
| 25–500 °C | 12.0 ×10⁻⁶/K |
Need these values in a handoff package? Download the full 17-4 PH datasheet PDF for your design review, sourcing notes, or drawing release.
Download DatasheetHeat Treatment
17-4 PH is usually printed, then aged. The thermal cycle is what takes the alloy from workable as-built condition to high-strength production condition.
Vacuum H900 follows two core steps:
- Solution anneal: 1040 °C ±15 °C for 30 minutes, then air cool below 32 °C.
- Age harden: 480 °C for 1 hour, then cool in air (H900 condition).
EOS also notes an atmospheric variant that ages at 460 °C for 1 hour, usually in argon, and reports similar high-strength results. We choose vacuum or atmospheric processing based on your specification package and inspection needs.
If your design benefits from lower hardness and more toughness, we can move to H925, H1025, H1075, H1100, or H1150 instead. We also account for the typical ~0.2% dimensional shrinkage after heat treatment when we plan machining stock and critical fits.
Source and Notes
Frequently Asked Questions
What is 17-4 PH stainless steel in DMLS?
17-4 PH is a martensitic precipitation-hardening stainless steel. In DMLS it prints near net shape first, then usually goes through solution anneal and aging to reach its target hardness and strength. The chemistry follows ASTM A564 (UNS S17400), so it is a familiar alloy family for many engineering teams.
How does 17-4 PH compare with 316L or maraging steel?
17-4 PH generally lands between those two choices. Compared with 316L, it can reach much higher hardness and strength after aging. Compared with maraging steel, it keeps better corrosion resistance while still delivering strong mechanical performance. We usually choose among them based on corrosion exposure, required hardness, and post-processing plan.
Do DMLS 17-4 PH parts need heat treatment?
In most cases, yes. As-built properties are usable, but precipitation hardening is what gives 17-4 PH its full performance. The common route is solution anneal followed by an aging cycle such as H900. We confirm the exact cycle from the load case, tolerance stack, and any downstream machining or inspection requirements.
What is H900 and when would I choose another aging condition?
H900 is a one-hour age at about 480 °C after solution annealing. It gives the highest hardness (around 42 HRC) and very high strength. If you need more toughness or ductility, higher-temperature aging conditions such as H925 through H1150 can be better, trading some hardness for a less brittle response.
What types of parts are typically printed in 17-4 PH?
We most often see engineering hardware that needs both strength and corrosion resistance: fasteners, shafts, tooling details, housings, and rugged assemblies for aerospace and defense programs. It is also used for medical and surgical instruments; as with all critical parts, we review the required alloy condition and validation plan before production.
Let's Start Your 17-4 PH Project
Send us your model and target requirements. We will confirm 17-4 PH fit, proposed heat treatment condition, tolerances, and timeline, then return a quote.