15-5 PH Stainless Steel
15-5 PH stainless steel is precipitation-hardening stainless steel with a chromium content of 15%, 5% nickel, and 3-5% copper. Molybdenum, columbium (niobium), and tantalum are also present at trace levels. The letter "PH" stands for "precipitation-hardening," which refers to the technique of hardening steel by aging it at high temperatures.
This steel is well known for its excellent strength, hardness, and resistance to corrosion. 15-5 PH stainless steel offers high tensile strength, strong impact resistance, ductility, machinability, and weldability, and it can maintain these attributes in high-temperature conditions. 15-5 PH stainless steel's copper content also helps to increase its resistance to stress corrosion cracking, a kind of corrosion that occurs under tensile stress.
Because 15-5 PH stainless steel is martensitic stainless steel, it can be toughened by heat treatment to produce high strength and toughness. The aging process after heat treatment produces the precipitation of copper-rich phases, which increases the strength even further. Because of its great strength and corrosion resistance, it is well suited for usage in extreme conditions like those found in the aerospace and nuclear sectors. It can be heat-treated to boost its strength, and surface treatments can improve its corrosion resistance even more.
Chemical Composition (%) of 15-5 PH Stainless Steel
| CHEMICAL COMPOSITION (%) | ||||||||
| C, max | Mn, max | P, max | S, max | Si, max | Cr | Ni | Cu | Nb+Ta |
| 0.07 | 1.00 | 0.040 | 0.030 | 1.00 | 14.00-5.50 | 3.50-5.50 | 2.50-4.50 | 0.15-0.45 |
Mechanical Properties of 15-5 PH Stainless Steel
| MECHANICAL PROPERTIES | |||||
| Tensile Strength, MPa, min | Yield Strength, MPa, min | Elongation (%), min | Hardness, max | ||
| 550 | 200 | 40 | 187 HB | 90 HRB | 200 HV |
Physical Properties of 15-5 PH Stainless Steel
| PHYSICAL PROPERTIES | |||||
| Density | Modulus of Elasticity | Poisson's Ratio | Coefficient of Thermal Expansion | Thermal Conductivity | Electrical Conductivity |
| 7.8 g/cm³ | 190 GPa | 0.28 | 11 µm/m·K | 17 W/m·K | 2.2% IACS |
Features of 15-5 PH Stainless Steel
- High strength
- High toughness
- Good impact resistance
- Good ductility
- Good machinability
- Good weldability
- Good stress corrosion resistance
Applications of 15-5 PH Stainless Steel
15-5 PH stainless steel is widely utilized in the aerospace, chemical, petrochemical, and nuclear industries, as well as in the production of weapons and surgical implants.
- Aircraft components
- Nuclear Reactor Components
- High-performance valves and pumps
- Fasteners
Equivalent Grades of 15-5 PH Stainless Steel
| Grade | ASTM | UNS | WERKSTOFF NR. | DIN | ANFOR |
| 15-5 PH | XM-12 | S15500 | 1.4545 | X4CrNiCuNb16.4 | Z6CNU15.05 |
Machinability of 15-5 PH Stainless Steel
Although 15-5 PH stainless steel can be cold-worked to produce desired shapes or sizes, doing so reduces its ductility. Its machinability is good when annealed, but it can be difficult to machine if hardened by heat treatment.
