Stainless Steel 15-5 PH
Stainless Steel 15-5 PH (UNS S15500 / EN 1.4545)
Stainless Steel 15-5 PH (UNS S15500 / EN 1.4545) is a precipitation-hardening martensitic stainless steel developed to provide an excellent combination of high mechanical strength, good corrosion resistance, toughness, and dimensional stability.
The designation 15-5 PH refers to its nominal chromium and nickel content, while PH stands for Precipitation Hardening. The addition of copper and niobium allows the alloy to achieve high strength through controlled heat treatment and aging.
15-5 PH stainless steel offers a useful balance of strength, toughness, corrosion resistance, and fabrication performance, making it suitable for components where high mechanical performance and reliable dimensional stability are required.
It is widely used in aerospace, oil & gas, petrochemical, power generation, defense, marine, pump and valve manufacturing, and mechanical engineering.
Key Features
- Precipitation-hardening martensitic stainless steel
- High mechanical strength
- Good corrosion resistance
- Good toughness
- Good fatigue resistance
- Good wear resistance
- Good dimensional stability
- Good oxidation resistance
- Good machinability under suitable conditions
- Good weldability with appropriate procedures
- Multiple aging conditions available
- Excellent strength-to-weight ratio
Specifications
| Specification | Details |
|---|---|
| Grade | Stainless Steel 15-5 PH |
| UNS | S15500 |
| Werkstoff Number | 1.4545 |
| EN Designation | X5CrNiCu15-5 |
| Type | Martensitic Precipitation-Hardening Stainless Steel |
| Main Alloying Elements | Chromium, Nickel, Copper, Niobium |
| Common Standards | ASTM A564, ASTM A693, AMS 5862, EN 10088 |
| Heat Treatment Conditions | H900, H925, H1025, H1075, H1150 |
| Product Forms | Sheet, Plate, Round Bar, Forgings, Tube, Machined Components |
Equivalent Grades of Stainless Steel 15-5 PH
| Standard | Equivalent Grade |
|---|---|
| ASTM / UNS | 15-5 PH / S15500 |
| EN | 1.4545 |
| EN Designation | X5CrNiCu15-5 |
| JIS | SUSXM12* |
| AISI | 630 Modified* |
| AFNOR | Z5CNU15-5* |
*Equivalent designations should be verified according to the product form and applicable specification. 15-5 PH should not be considered identical to 17-4 PH.
Available Sizes
15-5 PH Sheets & Plates
- Thickness: 0.5 to 100 mm
- Width: Up to 2500 mm
- Length: Up to 12000 mm
15-5 PH Round Bars
- Diameter: 6 to 500 mm
15-5 PH Tubes & Pipes
- Outside Diameter: 6 to 610 mm
- Wall Thickness: According to applicable standards and project requirements
Actual availability depends on product form, heat-treatment condition, manufacturing standard, and project specifications.
15-5 PH Stainless Steel Chemical Composition
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 14.0 – 15.5 |
| Nickel (Ni) | 3.5 – 5.5 |
| Copper (Cu) | 2.5 – 4.5 |
| Niobium + Tantalum (Nb + Ta) | 0.15 – 0.45 |
| Manganese (Mn) | ≤ 1.00 |
| Silicon (Si) | ≤ 1.00 |
| Carbon (C) | ≤ 0.07 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
15-5 PH Stainless Steel Mechanical Properties
Mechanical properties depend on the selected aging condition and applicable product specification.
| Condition | Tensile Strength | Yield Strength |
|---|---|---|
| H900 | ≈ 1300 MPa and above | ≈ 1170 MPa and above |
| H925 | ≈ 1200 MPa and above | ≈ 1100 MPa and above |
| H1025 | ≈ 1070 MPa and above | ≈ 1000 MPa and above |
| H1075 | ≈ 1000 MPa and above | ≈ 860 MPa and above |
| H1150 | ≈ 930 MPa and above | ≈ 795 MPa and above |
H900 is generally selected when maximum strength and hardness are required, while H1150 provides improved toughness and ductility.
Physical Properties
| Property | Approximate Value |
|---|---|
| Density | 7.75 g/cm³ |
| Modulus of Elasticity | ≈ 200 GPa |
| Thermal Conductivity | ≈ 17 W/m·K |
| Specific Heat Capacity | ≈ 460 J/kg·K |
| Thermal Expansion Coefficient | ≈ 10.8 × 10⁻⁶ /°C |
| Melting Range | ≈ 1400 – 1450°C |
| Magnetic Properties | Magnetic |
Types of Stainless Steel 15-5 PH Products
15-5 PH Sheets & Plates
Used for aerospace components, high-strength mechanical parts, industrial equipment, and selected pressure applications.
15-5 PH Round Bars
Used for shafts, pins, valve stems, fasteners, machined parts, and mechanical components.
15-5 PH Forgings
Suitable for components requiring high mechanical strength, good toughness, and high metallurgical integrity.
15-5 PH Tubes & Components
Used in selected aerospace, energy, mechanical, instrumentation, and fluid-control applications.
15-5 PH Machined Components
Suitable for precision components requiring high strength, dimensional stability, and corrosion resistance.
Corrosion Resistance
Stainless Steel 15-5 PH provides good general corrosion resistance in atmospheric and many industrial environments.
It offers resistance to:
- Atmospheric corrosion
- Oxidation
- General corrosion
- Many industrial environments
- Selected chemical environments
- Certain stress-corrosion conditions
Corrosion performance depends on the aging condition, surface finish, and service environment.
For highly aggressive chloride or marine environments, grades such as 316L, Duplex 2205, or Super Duplex 2507 may be more suitable depending on the actual operating conditions.
Heat Resistance
15-5 PH offers good oxidation resistance and retains high mechanical strength at moderate elevated temperatures.
However, prolonged exposure to elevated temperatures can alter its microstructure and mechanical properties.
Therefore, the operating temperature, exposure duration, thermal cycling, and aging condition should be considered when selecting 15-5 PH for elevated-temperature applications.
Heat Treatment of Stainless Steel 15-5 PH
The primary advantage of 15-5 PH is its ability to achieve high strength through precipitation hardening.
Solution Treatment
The material is generally solution treated at approximately 1025–1050°C, followed by rapid cooling.
Aging Treatment
After solution treatment, controlled aging is performed to achieve the required mechanical properties.
Common aging conditions include:
- H900 – Very high strength and hardness
- H925 – High strength with improved toughness
- H1025 – Balanced strength and ductility
- H1075 – Improved toughness and strength balance
- H1150 – Higher toughness and ductility
The appropriate aging condition should be selected according to the required strength, hardness, toughness, ductility, and service environment.
Welding of Stainless Steel 15-5 PH
15-5 PH stainless steel has good weldability when appropriate and qualified welding procedures are followed.
Welding Processes
- GTAW / TIG
- GMAW / MIG
- SMAW
- SAW
- Laser Welding
Important Welding Considerations
Welding parameters should be carefully controlled to maintain the required metallurgical properties.
Depending on the initial condition and project requirements, post-weld heat treatment may be required to achieve the desired mechanical properties.
Welding procedures should be qualified according to the applicable standards and service requirements.
Fabrication
Machining
15-5 PH can be machined effectively under suitable conditions, particularly before final aging.
Common operations include:
- Turning
- Milling
- Drilling
- Grinding
- Threading
Forming
Forming is generally easier in the solution-treated condition than after precipitation hardening.
Cutting
- Laser cutting
- Plasma cutting
- Waterjet cutting
- Mechanical sawing
Surface Finishing
- Grinding
- Polishing
- Passivation
- Electropolishing
Applications
Aerospace Industry
- Structural components
- Aircraft components
- Precision parts
- Landing gear components
- High-strength mechanical components
Oil & Gas Industry
- Valve bodies
- Valve stems
- Pump components
- Mechanical components
- Control equipment
Petrochemical Industry
- Pump shafts
- Process equipment
- High-strength mechanical parts
- Precision components
Power Generation
- Turbine components
- Shafts
- Pumps
- Auxiliary equipment
Marine & Defense
- Shafts
- Mechanical components
- Precision parts
- High-load components
Mechanical Engineering
- Fasteners
- Pins
- Gears
- Shafts
- Machine components
- Precision-machined parts
Stainless Steel 15-5 PH in Tunisia, Algeria, Morocco & Libya
Stainless Steel 15-5 PH is suitable for industrial projects across Tunisia, Algeria, Morocco, and Libya where a combination of high mechanical strength, good corrosion resistance, toughness, and dimensional stability is required.
It is particularly suitable for aerospace, oil & gas, petrochemical, power generation, defense, marine, pump and valve manufacturing, and mechanical engineering.
The appropriate aging condition should be selected according to the required strength, hardness, toughness, ductility, and operating conditions.
15-5 PH vs 17-4 PH
| Property | 15-5 PH | 17-4 PH |
|---|---|---|
| Type | Martensitic precipitation-hardening | Martensitic precipitation-hardening |
| Chromium | ≈ 15% | ≈ 17% |
| Nickel | ≈ 4–5% | ≈ 3–5% |
| Mechanical Strength | Very High | Very High |
| Toughness | Very Good | Good to Very Good |
| Corrosion Resistance | Good | Good |
| Precipitation Hardening | Yes | Yes |
| Magnetic | Yes | Yes |
| Typical Applications | Aerospace, precision engineering | Aerospace, oil & gas, pumps, valves |
Conclusion
Stainless Steel 15-5 PH (UNS S15500 / EN 1.4545) is a precipitation-hardening martensitic stainless steel offering an excellent combination of high mechanical strength, good corrosion resistance, toughness, fatigue resistance, and dimensional stability.
Its various aging conditions allow its mechanical properties to be tailored to specific component requirements.
Available in sheets, plates, round bars, forgings, tubes, and machined components, Stainless Steel 15-5 PH is a high-performance material for demanding applications in aerospace, oil & gas, petrochemical, power generation, marine, defense, pump and valve manufacturing, and mechanical engineering across Tunisia, Algeria, Morocco, Libya, and international markets.
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