Grade dossier
17-4 PH Stainless Steel by Heat-Treatment Condition
A widely specified copper-bearing precipitation-hardening grade whose strength, toughness and corrosion performance depend on solution treatment and aging condition.
Identity before substitution
Define the grade, product and condition together
A familiar grade name is not a complete purchase specification. Product form, controlling standard, dimensions, condition, finish, certification and service environment determine whether the delivered material is suitable.
Composition control
ASTM A240/A240M flat-product chemistry
Limits are not heat analysis targets
The table summarizes grade limits commonly used for plate, sheet and strip. Pipe, tube, bar, forgings and cast products can be governed by different specifications. Always place the product standard and edition on the purchase order.
| C | 0.070 max |
|---|---|
| Mn | 1.00 max |
| Si | 1.00 max |
| P | 0.040 max |
| S | 0.030 max |
| Cr | 15.00-17.50 |
| Ni | 3.00-5.00 |
| Cu | 3.00-5.00 |
| Nb+Ta | 0.15-0.45 |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Condition A | Solution treated; final aging still required by design |
|---|---|
| H900 | Highest common strength; lower toughness than overaged conditions |
| H1025 | Balanced strength and toughness |
| H1150 | Lower strength with greater ductility and SCC margin |
Selection indicators
| Density | about 7.75 g/cm3 |
|---|---|
| Hardening | Single-step aging after solution treatment |
| Service temperature | Tie maximum exposure to aging condition |
| Procurement rule | Specify condition, form and governing standard |
Values depend on product form, thickness, test orientation, condition and governing edition. Use the mill test certificate and the purchase specification for acceptance, not a web table alone.
Selection boundary
Where 17-4 PH belongs and where to escalate
Grade selection is an environmental decision, not a popularity contest. Review the complete medium, temperature, geometry, fabrication, cleaning and inspection requirements.
Good reasons to evaluate it
Aerospace fittings and structural parts
Valve stems, shafts and gears
Pump components and fasteners
High-strength corrosion-resistant tooling
Reasons to stop and review
Ordering only “17-4” without condition
Using H900 values for Condition A material
Welding without a planned final heat treatment
Long exposure near or above the aging temperature without review
Fabrication route
Protect properties through cutting, forming and welding
Machine and form with the final aging route in mind.
Qualify welding and post-weld aging for the joint.
Keep sulfur-bearing lubricants and carbon-steel contamination controlled.
Verify hardness, tensile and toughness in the specified condition.
Supply definition
Product form changes the applicable requirements
Do not send an RFQ that names only the grade. State form, governing standard, dimensions, tolerances, finish, edge or end condition, quantity, certification and inspection.
Bar and shapes to ASTM A564/A564M
Plate, sheet and strip to ASTM A693 where applicable
Forgings to ASTM A705/A705M
AMS aerospace bar and forging products
Certificate checkpoint
Request heat identity, chemical analysis, mechanical results and compliance to the exact product specification. Add PMI, corrosion testing or supplementary examination only when the application requires it.
Interactive selection check
Test 17-4 PH against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 17-4 PH stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 17-4 PH replace another grade?
Only after checking the governing standard, composition, mechanical properties, corrosion exposure, fabrication route and certification. A commercial name is not a substitution approval.
Does the table apply to every product form?
No. Every aging condition has a different strength-toughness balance. The purchase order must name Condition A or the required H condition.
What should a 17-4 PH RFQ include?
Product form, standard and edition, UNS or EN designation, dimensions, tolerances, finish, quantity, service, fabrication, certificate and inspection requirements.
Sources, scope and RFQ
Use traceable grade data, then specify the actual product
ASTM A564/A564M requirements for UNS S17400 bars and shapes
Carpenter Technology Custom 630 (17-4) official datasheet
ASTM A693/A705 requirements for the ordered product form
Applicable AMS specification and design allowables