17-4 PH, UNS S17400, is the most widely used precipitation hardening stainless steel. A single, simple aging treatment after solution annealing develops strength from copper rich precipitates, so parts can be machined soft and hardened afterward with very little distortion or dimensional change.
The H condition sets the balance. H900 gives the highest strength, around 190 ksi tensile, with the lowest toughness and the most sensitivity to stress corrosion. Progressively higher aging temperatures through H1150 trade strength for toughness, ductility and stress corrosion resistance. Ordering 17-4 without naming the condition leaves the most important variable undefined.
We stock 17-4 PH as bar, plate, sheet and forgings in Condition A and in aged conditions H900 through H1150, and we can age to your call out.
Sizes and stock
- Round bar: up to 20" DIA
- Flat bar: up to 12" THK
- Sheet / plate: up to 4" THK
- Forgings: available by request
- Also available in tube, wire, coil and custom shapes
Processing capabilities
- Condition and precipitation hardening (H900 through H1150) to your call-out
- Shearing, waterjet, laser and saw cut blanks
- Centerless grinding, turning and polishing
- Penetrant dye and ultrasonic inspection, chemical assay and physical testing
Supplied in any temper or aged condition to your call-out. Stock is not held in aged tempers; we heat treat to order.
Specifications
Material is released to the applicable specification with mill test reports and, on request, independent lab verification.
Why engineers specify 17-4 PH
- High strength with useful corrosion resistance in one material
- Simple, low distortion age hardening after machining
- Strength and toughness selectable by aging condition
- Broad availability across bar, plate, sheet and forgings
Nominal chemistry
Percent by weight, nominal composition per the governing specification. The mill test report for your heat is the controlling document.
Typical mechanical properties
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Condition A (solution treated) | ~150 ksi | ~110 ksi | ~10% | 363 HBW max |
| H900 | 190 ksi min | 170 ksi min | 10% min | 40 HRC min |
| H1025 | 155 ksi min | 145 ksi min | 12% min | 35 HRC min |
| H1075 | 145 ksi min | 125 ksi min | 13% min | 32 HRC min |
| H1150 | 135 ksi min | 105 ksi min | 16% min | 28 HRC min |
Typical published values for reference only, not for design. Properties vary with section size, product form and processing. Order to the specification and condition your drawing requires.
Heat treatment and conditions
- 01Solution treat at 1900F, air cool to Condition A
- 02Age 1 hour at 900F for H900
- 03Age 4 hours at 1025F, 1075F or 1100F for the corresponding conditions
- 04Age 4 hours at 1150F for H1150, or use H1150M double age for maximum toughness
If our stock is not already in the condition you need, we can quote the material with the heat treatment performed before it ships.
Typical applications
- Valve bodies, stems and pump shafts
- Airframe fittings and structural hardware
- Fasteners and machined components
- Oil and gas and chemical process hardware
- Medical and food processing equipment
Fabrication notes
Machining
Austenitic grades work harden quickly, so use positive rake tooling, rigid setups, generous feed and flood coolant rather than light dwelling cuts. Martensitic and precipitation hardening grades machine most easily in the annealed or solution treated condition and are aged after rough machining.
Welding
Weldable by GTAW, GMAW, resistance and electron beam methods with matching or over alloyed filler. Stabilized and low carbon grades resist sensitization in the weld zone. Precipitation hardening grades are normally welded in the solution treated condition and aged afterward.
Forming
Sheet and strip form well in the annealed condition; cold worked tempers trade formability for strength. Allow for springback and, where specified, an intermediate anneal between draws.
17-4 PH compared with similar grades
15-5 PH
Same hardening system with a more fully martensitic structure, giving better transverse toughness in heavy sections.
13-8 PH
Higher strength and toughness with better stress corrosion resistance, at higher cost.
410 / 431
Martensitic stainless grades hardened by quench and temper, with more distortion and different corrosion behaviour.
Designations and cross reference
- Material family
- Stainless Steel
- Werkstoff (W.Nr)
- 1.4542
- EN designation
- X5CrNiCuNb16-4
- Series
- Precipitation Hardening
Working from an obsolete, foreign or superseded designation? Send it over and we will cross reference it to a current grade and specification.
Quality, testing and traceability
Supplied with mill test reports and heat traceability, with penetrant dye, ultrasonic, chemical assay, hardness, corrosion and mechanical testing available on request.
We are AS9100D and ISO 9001:2015 registered. If our stock does not already carry the inspection your specification requires, we can quote the material with that work performed. More on our quality system
Available forms
17-4 PH frequently asked questions
What is 17-4 PH?
17-4 PH, UNS S17400, is the most widely used precipitation hardening stainless steel. A single, simple aging treatment after solution annealing develops strength from copper rich precipitates, so parts can be machined soft and hardened afterward with very little distortion or dimensional change.
What forms is 17-4 PH available in?
We supply 17-4 PH in bar, sheet, plate, forging, tube, wire, coil. Custom sizes are converted from billet, and we can provide saw cut, waterjet or near net blanks so material arrives closer to your finished part.
What is the UNS or equivalent designation for 17-4 PH?
17-4 PH is designated Werkstoff 1.4542, EN X5CrNiCuNb16-4. If your drawing calls out an obsolete or foreign designation we can cross reference it and confirm the equivalent before you order.
What specifications can 17-4 PH be supplied to?
Commonly ordered specifications include AMS 5643, AMS 5622, AMS 5604, ASTM A564, ASTM A693. Material is released to the specification and condition on your purchase order, with mill test reports supplied as standard.
What conditions can 17-4 PH be ordered in?
We can supply Condition A (solution treated), H900, H1025, H1075, H1150. If our stock is not already in the condition you need, we can quote it with the heat treatment performed before shipment.
Can you cut 17-4 PH to size?
Yes. Saw cutting, waterjet, laser and shearing are available, along with trepanning, gun drilling, lathe turning and CNC machining, so you can order blanks or rough machined pieces rather than full lengths.
Do you provide test reports and additional testing on 17-4 PH?
Every order ships with mill test reports and heat traceability. If your print calls for ultrasonic inspection, penetrant dye, magnetic particle, chemical assay, micrography, hardness or mechanical testing and our stock does not already carry it, we can quote the material with that work performed.
Can 17-4 PH be supplied to DFARS domestic melt requirements?
Tell us at quote stage if the order is DFARS or domestic melt restricted and we will confirm availability against that requirement before you commit.
What do you need to quote 17-4 PH?
Grade, form, dimensions, quantity, specification and condition, plus any testing or certification requirements and the date you need it. Send a drawing if you have one. Quotes are typically ready within 24 hours.
How does 17-4 PH compare with 15-5 PH?
Same hardening system with a more fully martensitic structure, giving better transverse toughness in heavy sections.