Wexmar offers CNC machining of 15-5 PH stainless steel (UNS S15500, XM-12) for aerospace fittings, valve components and defense hardware. 15-5 PH is a close relative of 17-4 PH, produced with lower delta ferrite and often by vacuum arc remelting, which gives it more uniform properties and better toughness across the grain. Engineers usually specify it when a part is loaded in several directions or when a program specification calls it out by name.
15-5 PH machinability
In Condition A, 15-5 PH has an approximate machinability rating of 40, with AISI 1212 steel at 100. At the spindle it feels much like 17-4 PH: tough, abrasive and hot at the edge, but not as prone to work hardening as 316. Premium melt material is cleaner, which can help surface finish, but mill pricing for VAR or ESR bar is higher and lead times can be longer. We check availability and stock sizes at the quoting stage so the buy is not a surprise.
Many 15-5 PH prints reference AMS 5659, which governs premium melt bar and forgings, and some also reference AMS 5862 or customer-specific material specs. Before quoting, we confirm which spec and condition apply, since a certificate that names the wrong spec can hold up an entire shipment at receiving inspection. When the specified bar is on long lead, we will tell you up front rather than substitute material.
Tolerances and finish
Typical 15-5 PH parts are held to plus or minus 0.001 in. on general features and plus or minus 0.0005 in. on selected bores and diameters. Surface finish of 32 Ra is typical on turned features, with 63 Ra common on milled pockets and faces. Critical dimensions are verified on our Brown and Sharpe CMMs, with gages calibrated under an ISO/IEC 17025-aligned program, and first-article reports in AS9102 format are available. These are typical results, not guarantees.
Machining practice and common problems
Most of the trouble with 15-5 PH comes from planning, not cutting. Points we address before the first chip:
- Condition at purchase. Many aerospace prints call for H1025 or H1150 material, which machines well and avoids post-machining aging. Parts machined in Condition A must allow for the small contraction that occurs during aging.
- Tool selection. Coated carbide with a tough edge prep, positive rake for finishing, and ceramic or CBN is generally unnecessary.
- Heat control. High-pressure coolant through the tool on drills and boring bars keeps edges from cratering.
- Grain direction. Although toughness is better than 17-4, long slender parts still benefit from balanced stock removal to limit bow.
- Burrs. Aged material produces small, hard burrs that must be removed before inspection and finishing.
Heat treat and surface finishing
Aging to H900, H1025, H1075, H1100 or H1150, with or without double aging, is performed through qualified outside processors to AMS 2759 or the customer's spec. Passivation to AMS 2700 or ASTM A967 is also completed through qualified outside processors. Hardness and processor certs travel with the shipment along with material certs and heat-lot traceability.
Typical 15-5 PH parts
- Aircraft fittings, clevises and link pins
- Valve stems, balls and seats for high-pressure service
- Actuator pistons and housings
- Gear and spline shafts where corrosion resistance matters
Round parts run on our Mazak and Doosan lathes with live tooling, small diameters on Maier Swiss machines, and prismatic fittings on horizontal machining centers where pallet changers and 4-axis indexing reach multiple faces in one setup. See the machine list for the full equipment set.
Cost index comparison
| Material | Approx. machinability (1212 = 100) | Cost index vs 6061 | Notes |
|---|---|---|---|
| 6061-T6 aluminum | ~180 | 1.0 | Baseline |
| 410 stainless (annealed) | ~55 | 2.0 | Hardenable martensitic |
| 17-4 PH (Cond A) | ~40 | 2.8 | Common PH grade |
| 15-5 PH | ~40 | 3.0 | Premium melt, better toughness |
| Nitronic 50 | ~22 | 4.5 | Austenitic, very corrosion resistant |
| Ti-6Al-4V | ~22 | 5.0 | Lighter, higher material cost |
Numbers are typical and illustrative for a comparable part; actual quotes depend on geometry, quantity, tolerances and mill pricing.
Industries served
15-5 PH stainless machining services at Wexmar support aerospace hardware suppliers, defense build-to-print programs, and industrial valve and fluid power OEMs. Our Canastota, NY shop is SAM.gov active with CAGE 16AD7, and DFARS-compliant specialty-metals sourcing is available. For the related grade, see 17-4 PH stainless, or read about our inspection and quality process.
Getting a quote
Include the material spec, required condition and any finishing callouts. You can upload a drawing for an instant estimate or call (315) 400-2654. A human estimator confirms every quote.