17-4 PH Stainless Steel (UNS S17400) is a difficult-to-machine material that we run regularly for export customers. It has a density of 7.80 g/cm3, a tensile strength of 1310 MPa and a typical hardness of HRC 44 (H900). Those numbers make it the right choice for valve stems and pump shafts, and a poor choice when cost or corrosion resistance matters more than mechanical performance.
On our machines we hold +/-0.02 mm on turned and milled features and reach Ra 1.6 um where the drawing calls for it. Standard lead time for 17-4 PH Stainless Steel parts is 4-8 working days, including material procurement, machining and any finishing operation you specify.
17-4 PH Stainless Steel: key properties
| Property | Value |
|---|---|
| UNS / designation | S17400 |
| Density | 7.80 g/cm3 |
| Tensile strength | 1310 MPa |
| Hardness | HRC 44 (H900) |
| Machinability | Difficult |
| Suggested cutting speed (carbide) | 60-90 m/min |
| Relative material cost | 4 of 5 |
Machining 17-4 PH Stainless Steel: what to plan for
- Machine in annealed then age
- Post-age distortion
- Tool life drops sharply at H900
Cutting speed for 17-4 PH Stainless Steel with carbide tooling sits around 60-90 m/min. Going faster burns the edge; going much slower causes rubbing and a poor surface. Flood coolant is not optional here. If your part has thin walls or a lot of stock to remove, say so in the RFQ — we plan roughing, stress relief and finishing as separate operations when the geometry demands it.
Parts we machine in 17-4 PH Stainless Steel
- Valve stems
- Pump shafts
- Aerospace fasteners
- Mould inserts
Most 17-4 PH Stainless Steel work arrives as 2D drawings with a mix of critical and non-critical features. Loosening tolerance on the non-critical ones is the fastest way to cut cost, and we will tell you which features those are before we quote.
Tolerances, finish and lead time
| Item | Capability |
|---|---|
| General tolerance | +/-0.02 mm |
| Achievable surface finish | Ra 1.6 um |
| Minimum wall thickness | 0.8 mm (aluminium) / 1.0 mm (steel and stainless) |
| Typical lead time | 4-8 working days |
| Prototype quantity | 1 piece |
| Production quantity | 10 to 50,000 pieces |
Frequently asked questions
What is the lead time for 17-4 PH Stainless Steel parts?
Standard is 4-8 working days from drawing release, assuming the material is in stock. Exotic grades and cast forms can add 5 to 10 days. Finishing such as anodizing or plating adds 3 to 5 days.
What tolerance can you hold in 17-4 PH Stainless Steel?
+/-0.02 mm is routine on turned and milled features. Tighter than that is possible on specific features by grinding or lapping, but it is quoted separately because it changes the process.
Do you keep 17-4 PH Stainless Steel in stock?
We hold common sizes of 17-4 PH Stainless Steel and buy mill-certified stock for everything else. Material certificates are supplied with the parts on request.
Can you supply 17-4 PH Stainless Steel parts with a certificate of conformity?
Yes. We issue a dimensional report, a material certificate and a certificate of conformity as standard for production orders, and full PPAP or AS9102 paperwork when the programme requires it.
Related pages
- Materials — the full index for this section.
- 440C Stainless CNC Machining for Bearings and Valves
- 420 Stainless Steel CNC Machining: Hardened Parts
- 316L Stainless Steel CNC Machining for Marine and Medical
- Titanium Grade 5 (Ti-6Al-4V) CNC Machining Guide
- Instant CNC quote
- Tolerance quick reference
- Frequently asked questions
Get a price for your part
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