15-5 PH Stainless (XM-12, UNS S15500)
17-4 PH strength with better transverse toughness — the premium PH stainless for forgings, pump shafts and aerospace and valve fasteners.
What 15-5 PH is.
15-5 PH is a refinement of 17-4 PH with slightly less chromium and more nickel, balanced to eliminate the delta ferrite stringers that give 17-4 its directional properties. The result is the same range of age-hardened conditions, H900 to H1150M, apart from H1150D, with better transverse ductility and impact strength, especially in large sections.
ASTM A564 governs the bar; we machine 15-5 components and fasteners and have them aged to the ordered condition.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.07 |
| Manganese | Mn | — | 1.00 |
| Phosphorus | P | — | 0.040 |
| Sulfur | S | — | 0.030 |
| Silicon | Si | — | 1.00 |
| Chromium | Cr | 14.00 | 15.50 |
| Nickel | Ni | 3.50 | 5.50 |
| Copper | Cu | 2.50 | 4.50 |
| Niobium | Nb | 0.15 | 0.45 |
Values per ASTM A564/A564M-19a Table 1 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition | Aging treatment | Tensile strength, min (ksi) | Yield strength, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness, min | Charpy V-notch, min (ft·lbf) |
|---|---|---|---|---|---|---|---|
| H900 | 900 °F, 1 h | 190 | 170 | 10 | 35 | 40 HRC / 388 HBW | — |
| H925 | 925 °F, 4 h | 170 | 155 | 10 | 38 | 38 HRC / 375 HBW | 5 |
| H1025 | 1025 °F, 4 h | 155 | 145 | 12 | 45 | 35 HRC / 331 HBW | 15 |
| H1075 | 1075 °F, 4 h | 145 | 125 | 13 | 45 | 32 HRC / 311 HBW | 20 |
| H1100 | 1100 °F, 4 h | 140 | 115 | 14 | 45 | 31 HRC / 302 HBW | 25 |
| H1150 | 1150 °F, 4 h | 135 | 105 | 16 | 50 | 28 HRC / 277 HBW | 30 |
| H1150M | 1400 °F, 2 h, air cool, then 1150 °F, 4 h | 115 | 75 | 18 | 55 | 24 HRC / 255 HBW | 55 |
Values per ASTM A564/A564M-19a Table 4 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Aging temperatures per A564 Table 4 are suggested values that may be varied to obtain the required properties; transverse values are lower and are listed in the specification.
| Condition | Solution treatment | Hardness, max |
|---|---|---|
| A (solution treated) | 1900 ± 25 °F (1040 °C), cool to below 90 °F | 38 HRC / 363 HBW |
Values per ASTM A564/A564M-19a Table 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How 15-5 PH ships from Houston.
- Studs, bolts and cap screws in any A564 condition
- Pump shafts, impellers and valve stems machined to print
- Aerospace and defence components
- Certified A564 bar, solution treated or aged
15-5 PH fasteners we make.
Every item is manufactured to your drawing or standard in 15-5 PH, imperial or metric, with an EN 10204 3.1 certificate.
What is 15-5 PH?
15-5 PH (UNS S15500, A564 Type XM-12) was developed as a ferrite-free 17-4. By trimming chromium to about 15 percent and raising nickel to about 4.5 percent, the alloy solidifies without the delta-ferrite stringers that make 17-4 weaker across the grain. It heat treats in the same way, with seven conditions from H900 to H1150M (there is no H1150D for XM-12) and strength minimums that match 17-4 PH, with slightly different reduction-of-area minima, but its transverse ductility and Charpy values are markedly better, which is why aerospace and forging specifications prefer it for thick sections and high-integrity parts.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or alloy marking 15-5 with the condition suffix and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
- Age-hardening cycle and condition recorded on the certificate
17-4 PH Stainless (Type 630, UNS S17400)
The high-strength stainless — up to 190 ksi in H900, or 115 to 135 ksi with real toughness in the H1150 conditions — for pump shafts, valve stems, subsea and aerospace fasteners.
ASTM A1082 bolting · ASTM A564 bar17-7 PH Stainless (Type 631, UNS S17700)
The spring-and-sheet PH stainless — formable in the annealed condition, then transformed and aged to 185 ksi for springs, washers, clips and high-strength small fasteners.
ASTM A1082 bolting · ASTM A276 / A479 bar · ASTM A182 F51 / F60Duplex 2205 Stainless (UNS S31803 / S32205)
Twice the yield strength of 316 with far better chloride stress-corrosion resistance — the standard duplex for offshore, seawater and sour-service bolting.