Products Features
Ultra-high strength and excellent lateral toughness (core advantage)
The core advantage of 15-5PH lies in its ability to achieve extremely high strength and hardness through simple heat treatment while maintaining excellent transverse toughness. After solution treatment, this alloy exhibits a low-carbon martensitic structure with a hardness of ≤38 HRC. Precipitation hardening can be obtained via a single aging treatment at 480-620°C, and the strength level can be flexibly adjusted by varying the aging temperature.
Comparison of Mechanical Properties at Different Temperature Time Effects (AMS 5659 Standard):
|
Aging Condition |
Tensile Strength (MPa) |
Yield strength 0.2% (MPa) |
Elongation A50 (%) |
Reduction of cross-sectional area (%) |
|
480℃ (H900) |
≥ 1310 |
≥ 1172 |
≥ 10 |
≥ 35 |
|
550℃ (H1025) |
≥ 1069 |
≥ 1000 |
≥ 12 |
≥ 40 |
|
580℃ (H1075) |
≥ 1000 |
≥ 862 |
≥ 13 |
≥ 45 |
|
620℃ (H1150) |
≥ 931 |
≥ 724 |
≥ 16 |
≥ 50 |
Its yield strength is 3-5 times that of 304 stainless steel (≈220 MPa). More importantly, 15-5PH exhibits significantly better transverse toughness than 17-4PH. At the same strength level, 15-5PH has higher elongation and reduction of area than 17-4PH, with the advantage being even more pronounced in large-section products.
Good corrosion resistance
The corrosion resistance of 15-5PH is equivalent to that of 304 stainless steel (SS 304), performing well in atmospheric environments, fresh water, dilute acid, and salt solutions. Its high chromium content (14-15.5%) forms a dense Cr₂O₃ passivation film, providing fundamental corrosion resistance. Compared to 17-4PH, 15-5PH exhibits comparable or slightly superior resistance to pitting and stress corrosion cracking, particularly with better microstructural uniformity in large-section products, resulting in lower risk of localized corrosion.
However, note that 15-5PH should be carefully evaluated for long-term use in high-temperature environments with high chloride concentrations, as its corrosion resistance is not as good as that of austenitic stainless steels (e.g., 316L). This alloy is not suitable for strongly acidic or high-chloride environments.
Excellent heat treatment simplicity
One of the most significant advantages of 15-5PH is its simple heat treatment process-the 'single-step aging hardening' property is a core advantage for its engineering applications. Similar to 17-4PH, 15-5PH has a martensitic structure after solution treatment and can be strengthened with a single aging treatment, eliminating the need for complex quenching processes. This significantly reduces processing costs and deformation risks.
Solution treatment:
Heat to 1020-1060°C, hold at temperature, then quench rapidly (oil quenching or air cooling) to obtain a martensitic structure.
Timed heat treatment:
Select a temperature within the range of 480-620°C for single aging. After holding at this temperature for 1-4 hours, air cool. Strengthening is achieved through the dispersed precipitation of the ε-Cu phase.
Note:
During 15-5PH heat treatment, dimensional changes are minimal (approximately 0.05-0.10%), which is superior to 17-4PH, making it suitable for applications with high precision dimensional control requirements.
Good machining and welding properties
15-5PH exhibits good hot and cold workability, allowing it to be forged, rolled, and stamped. In the solution-annealed condition, it has moderate hardness (≤38 HRC) and better machinability than 17-4PH, making it suitable for forming processes such as turning, milling, drilling, and grinding using conventional machining methods.
It has good weldability and can be joined using conventional welding methods (TIG, MIG, SMAW), with welding procedures similar to those for 300 series stainless steels. It is recommended to use matching 15-5PH filler materials during welding, and the mechanical properties of the heat-affected zone can be restored through aging heat treatment after welding. Compared to conventional martensitic stainless steels, 15-5PH exhibits significantly improved weldability and toughness due to its ultra-low carbon design and niobium addition.
Note: This alloy is ferromagnetic, unlike austenitic stainless steels, and is therefore not suitable for applications requiring non-magnetism (such as MRI equipment and precision electronic instruments).
Excellent fatigue resistance and long-term microstructural stability
15-5PH exhibits excellent fatigue resistance. Its combination of high strength and good toughness enables it to perform exceptionally well under cyclic loading conditions. Under long-term moderate-temperature aging (approximately 300°C), its microstructure (with about 1% austenite content and copper precipitation phases) demonstrates significant long-term stability, which is beneficial for maintaining mechanical properties during extended service.
Long-term thermal stability:
15-5PH exhibits good microstructural stability and maintains stable age-hardening effects when in service at temperatures up to 300°C for extended periods.
Typical applications:
critical components such as aircraft engine pylon structural parts that need to maintain mechanical properties under long-term moderate-temperature service conditions.
Technical Specifications
Chemical Composition(ASTM A564 / UNS S15500)
|
Element |
Standard Requirements |
Notes |
|
Cr |
14.0 - 15.5% |
Core elements that form a dense passivation film, providing basic corrosion resistance |
|
Ni |
3.5 - 5.5% |
Austenitizing elements, adjust the martensitic transformation point, improve toughness |
|
Cu |
2.5 - 4.5% |
The core precipitated and hardened elements, which form ε-Cu phases during aging treatment, resulting in dispersion strengthening |
|
Nb (+Ta) |
0.15 - 0.45%(≥5×C) |
Carbide-forming elements (NbC) refine grains and participate in precipitation strengthening |
|
C |
≤ 0.07% |
Ultra-low carbon design minimizes carbide segregation to the maximum extent, ensuring weldability and toughness. |
|
Mn |
≤ 1.00% |
Deoxidizer |
|
Si |
≤ 1.00% |
Deoxidizer |
|
P |
≤ 0.030% |
Impurity elements, strictly controlled |
|
S |
≤ 0.015% |
Impurity elements, strictly controlled |
|
Fe |
Remaining quantity |
Matrix element |
Physical Properties
|
Property |
Value/Range |
Test Conditions |
|
Density |
7.75 - 7.80 g/cm³ |
Room Temperature (20°C) |
|
Melting Point |
1400 - 1440°C |
- |
|
Resistivity |
≈ 0.80 μΩ·m |
Room Temperature |
|
Thermal Conductivity |
≈ 16 W/(m·K) |
Room Temperature |
|
Coefficient of Thermal Expansion (20-100°C) |
≈ 10.9 × 10⁻⁶ /K |
Room temperature to 100°C |
|
Elastic modulus (Young's modulus) |
≈ 200 GPa |
Room Temperature |
|
Poisson's ratio |
≈ 0.27 - 0.30 |
Room Temperature |
|
Magnetism |
Magnetic (ferromagnetic) |
Martensitic structure, which exhibits ferromagnetism |
Mechanical Properties (Solution-treated and aged, typical values, AMS 5659)
|
Aging Condition |
Tensile Strength (MPa) |
Yield strength0.2% (MPa) |
Elongation A50 (%) |
Reduction of cross-sectional area (%) |
Hardness (HRC) |
|
|
480°C (H900) |
≥ 1310 |
≥ 1172 |
≥ 10 |
≥ 35 |
40-47 |
|
|
550°C (H1025) |
≥ 1069 |
≥ 1000 |
≥ 12 |
≥ 40 |
34-42 |
|
|
580°C (H1075) |
≥ 1000 |
≥ 862 |
≥ 13 |
≥ 45 |
31-38 |
|
|
620°C (H1150) |
≥ 931 |
≥ 724 |
≥ 16 |
≥ 50 |
28-37 |
|
Note: The strength level of 15-5PH can be flexibly adjusted by the aging temperature. The lower the aging temperature, the higher the strength, but the elongation decreases; conversely, as the aging temperature increases, strength decreases, while plasticity and toughness improve.
High-temperature performance
15-5PH maintains a high level of strength within the range of ≤ 300°C, and the recommended maximum usage temperature should not exceed 315°C. Beyond this temperature, the precipitation-hardening phase will gradually coarsen, leading to a decrease in strength.
|
Temperature |
Performance maintenance status |
Explanation |
|
Room Temperature (20°C) |
100%(Peak) |
The H900 alloy can achieve a tensile strength of up to 1310 MPa |
|
100°C |
≥ 90% |
The strength is well maintained |
|
200°C |
≥ 85% |
It can still maintain high strength |
|
300°C |
≥ 75% |
It is recommended to use the upper limit for a long period |
|
> 400°C |
Significant decline |
Precipitate coarsening leads to a rapid decline in strength |
Long-term thermal stability:
15-5PH exhibits good microstructural stability during long-term service at temperatures ≤ 300°C:
Austenite content remains stable:
The residual/retrogression austenite content of approximately 1% remains almost unchanged during long-term aging processes.
The copper precipitation phase remains stable:
the strengthening precipitation phase does not significantly coarsen during long-term moderate-temperature aging processes.
Long-term Aging Hardening Effect:
During long-term aging at approximately 300°C, chromium composition fluctuations (spinodal decomposition) can provide an additional hardness increment.
Prolonged exposure above 400°C may lead to the precipitation of the G phase (Ni-Mn-Si enriched phase) and intensified Cr spinodal decomposition, which can affect toughness.
Heat treatment system
The final performance of 15-5PH is highly dependent on the heat treatment regime, with common specifications as follows:
1. Solution treatment (to obtain martensitic structure):
Heat to 1020-1060°C, hold for a sufficient time (approximately 30-60 minutes per inch of thickness), and then cool rapidly (oil quench or air cool). This results in a low-carbon martensitic structure, preparing it for subsequent aging and precipitation hardening. The solution-treated hardness is ≤38 HRC, with good machinability.
2. Aging Temperature treatment (precipitation hardening to achieve the target strength grade):
Select the holding temperature based on the target strength grade:
|
Aging Condition |
Aging Temperature |
Holding Time |
Cooling method |
Target Strength Level |
|
H900 |
480°C |
1 hour |
Air-cooled |
Maximum intensity |
|
H925 |
495°C |
4 hour |
Air-cooled |
Ultra-high strength |
|
H1025 |
550°C |
4 hour |
Air-cooled |
High strength plus good toughness |
|
H1075 |
580°C |
4 hour |
Air-cooled |
Medium strength + good toughness |
|
H1100 |
593°C |
4 hour |
Air-cooled |
Medium strength + good toughness |
|
H1150 |
620°C |
4 hour |
Air-cooled |
Optimal toughness and corrosion resistance |
Note:
- Solution treatment should be performed before the final mechanical machining, and aging treatment can be carried out after machining to take advantage of the better machinability of the solution-treated state.
- The lower the aging temperature, the higher the strength and the lower the elongation; as the aging temperature increases, strength decreases while ductility and toughness improve.
- The dimensional change after heat treatment is approximately 0.05-0.10%, which is better than 17-4PH, making it suitable for applications with precise dimensional control requirements. It is recommended to perform aging heat treatment after welding to restore the mechanical properties of the heat-affected zone.
Applicable Media
Atmospheric Environment:
Exhibits good corrosion resistance in both normal and industrial atmospheres.
Freshwater:
Demonstrates excellent corrosion resistance in freshwater and drinking water.
Dilute Acids:
Shows good corrosion resistance in dilute nitric acid, dilute acetic acid, and dilute phosphoric acid.
Salt Spray Environment:
Its corrosion resistance in marine salt spray environments is comparable to that of 304 stainless steel, but there is a risk of pitting and crevice corrosion.
Oil and Gas Media:
Suitable for oil and gas environments containing CO₂; cautious evaluation is required in acidic environments containing H₂S.
Food Industry Media:
Meets the requirements for food contact materials.
Note: 15-5PH is not resistant to extreme highly corrosive media such as high-temperature concentrated hydrochloric acid, hydrofluoric acid, and boiling sulfuric acid. Its corrosion resistance is limited in high-temperature environments containing high concentrations of chlorides, and it is not recommended for use in strongly acidic or high-chloride ion environments.
15-5PH (XM-12/UNS S15500) is specifically designed for demanding applications that require a combination of high strength, high toughness, excellent transverse properties, and good corrosion resistance. It is particularly suitable for large-section high-performance structural components and is recommended for use in the following areas:
Application Fields
-
Aerospace (Core Applications)
● Aircraft structural components: wing spars, fuselage frames (such as Boeing 737-600)
● Landing Gear Components: Main Landing Gear Front Axle Neck Bracket Steel Pin (Boeing 767, etc.)
● Engine Components: Compressor Disk, Blades, High-Strength Fasteners
● Various components such as hatch cover latches, springs, etc. -
Marine Engineering and Offshore Platforms
● Offshore platform structural components, helicopter decks
● Ship propeller shafts, pump valve components, submarine valve assemblies
● Fasteners for High-Salt Fog Environments (Recommended to be used with Surface Treatment) -
Petrochemicals and Energy
● Nuclear industry waste drums, nuclear power plant valve stems
● High-pressure valves (valve core/valve stem), pump shaft
● High-strength bolts, reactor shaft components, corrosion-resistant load-bearing structures
● Gears, couplings, high-strength mechanical components -
Medical Precision
● high-strength surgical instruments, orthopedic tools, and dental drills (dimensionally stable + biocompatible) -
General Machinery Manufacturing
● High-strength shafts, turbine components, molds
● Precision mechanical components
Delivery and Customization
We offer flexible and reliable supply chain solutions to ensure you receive 15-5PH materials that perfectly match your project requirements.
|
Form |
 Sheet/Plate
|
 Bar/Rod
|
 Pipe / Tube
|
 Strip/Sheet Coil
|
 Wire/Wire Rod
|
|---|---|---|---|---|---|
|
Conventional Range |
Thickness: 0.5 - 100 mm |
Diameter Φ6-500mm |
Outer diameter Φ10-300mm |
Thickness: 0.1 – 3.0 mm |
Diameter Φ0.5-10mm |
|
Customization Capability |
Hot-rolled or cold-rolled plates, ultra-thin plates (starting from 0.1mm), stamped parts, length-cutting to specified dimensions, special surface treatments (pickling, polishing) |
Forged bars, hot-rolled bars, polished bars, shaped bars, and different heat treatment conditions (annealing, stabilization) |
Seamless Tubes/ Welded Tubes (Compliant with ASTM A789/ A790), Fixed-Length Cutting, U-Tubes |
Precision strip materials, stamping coil stock, laminated blanking, non-standard width, special protective film |
Precision drawing, spring wire, welding filler wire |
Why Choose Us? - Reliable Engineering Technology. Dependable Delivery.
We are not just a supplier, but a trusted materials partner for you in China.
Vertically Integrated Production
Own 20,000㎡ facility with 10+ automated lines (8,000+ tons/year). In-house tooling & die center enables rapid customization and effective cost control - no middleman markup.
Strict Quality Control at Every Stage
Full traceability across key QC checkpoints throughout production. 100% compliant with ASTM/ASME, EN, and GB standards. Material test reports available with every shipment.
Reliable Delivery & Export Packaging
10+ years exporting to Europe, North America, Southeast Asia & Middle East with waterproof and anti-rust protection, combined with flexible shipping options ensures safe and on-time arrival.
Sample Validation Before Mass Production
We provide free samples for quality verification, allowing you to place bulk orders only after approval. We ensure consistency from sample to mass production by accurate dimensional measurement and transparent manufacturing.
FAQ
Q: What are the main advantages of 15-5PH?
Q: What are the differences between 15-5PH and 17-4PH? How to choose between them?
Q: What is the difference between 15-5PH stainless steel and 304 stainless steel? How to choose?
Q: What is the maximum operating temperature for 15-5PH?
Q: What is the welding performance of 15-5PH?
Q: What is the corrosion resistance of 15-5PH?
Q: Can 15-5PH replace 17-4PH or 304?
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