15-5PH Stainless Steel (AMS 5659 / AMS 5862)
Tailwind Aerospace Solutions supplies 15-5PH precipitation-hardening stainless steel to AMS 5659 and AMS 5862 specifications. This martensitic stainless alloy (UNS S15500) was developed as a refinement of 17-4PH, offering improved transverse toughness and better performance in larger cross sections. If your drawing calls out AMS 5659 or AMS 5862, we stock certified 15-5PH ready to ship with full material traceability.
What is 15-5PH Stainless Steel?
15-5PH is a martensitic precipitation-hardening stainless steel containing roughly 15% chromium and 5% nickel, with copper added to enable age hardening. It was developed in the 1960s to address limitations engineers encountered with 17-4PH, particularly around consistency and toughness in thicker sections.
Chemical Composition & UNS Designation (UNS S15500)
15-5PH is registered under UNS S15500. Its chemistry is closely related to 17-4PH, with tighter inclusion control and a reduced delta ferrite content contributing to its improved properties:
| Element | Min % | Max % |
|---|---|---|
| Chromium (Cr) | 14.00 | 15.50 |
| Nickel (Ni) | 3.50 | 5.50 |
| Copper (Cu) | 2.50 | 4.50 |
| Columbium + Tantalum (Cb+Ta) | 0.15 | 0.45 |
| Carbon (C) | 0.07 | |
| Iron (Fe) | Balance | |
Key Properties (Strength, Corrosion Resistance, Toughness)
15-5PH delivers high tensile and yield strength alongside excellent corrosion resistance, and it can be heat treated to a range of conditions depending on the strength and ductility your application requires. Its combination of properties makes it a reliable choice where both mechanical performance and corrosion resistance matter, without the added cost of higher alloyed grades like 13-8PH.
15-5PH vs. 17-4PH: What's the Difference?
15-5PH was engineered specifically to improve on 17-4PH's limitations. Compared to 17-4PH, 15-5PH offers better transverse toughness and ductility, more consistent mechanical properties in larger cross sections, and improved forgeability. Both alloys are readily weldable, but 15-5PH is generally the better choice when a part's cross section is thick enough that 17-4PH's properties become inconsistent through the material. For applications demanding even greater toughness than 15-5PH provides, 13-8PH stainless steel is worth considering as a step up.
15-5PH Specifications
15-5PH is governed by two primary AMS specifications, split by product form.
AMS 5659 covers 15-5PH bar and forgings. This specification includes two melting practices: AMS 5659 Type 1 covers vacuum melted material, while AMS 5659 Type 2 covers electroslag remelted (ESR) material for applications requiring even tighter cleanliness control.
AMS 5862 is the specification for 15-5PH sheet, strip, and plate. If your drawing calls for 15-5PH in flat rolled form rather than bar, this is the applicable spec.
15-5PH cross-references to ASTM A564 for bar and forgings, and ASTM A693 for plate. These cross-references are useful when a purchase order or customer specification references ASTM standards rather than AMS directly.
Available Forms & Shapes
15-5PH is stocked across a wide range of shapes.
Round bar is available in both vacuum melted and ESR grades, with typical stock ranging from small diameters suited to precision machined parts up to larger diameters for structural components.
Flat bar and square bar are commonly stocked for applications requiring a rectangular or square cross section, including brackets, fittings, and machined structural parts.
Sheet and plate are supplied under AMS 5862 in a range of standard thicknesses, suited to structural panels and components that begin as flat stock before machining or forming.
Need 15-5PH Stainless Steel?
Get certified round bar, flat bar, sheet, or plate with full traceability documentation.
Heat Treatment & Tempers (H900, H925, H1025, H1075, H1100, H1150)
15-5PH is supplied in the solution annealed condition and can be age hardened by the customer to a range of tempers depending on the strength and ductility required:
| Condition | Tensile Strength (min) | Yield Strength (min) |
|---|---|---|
| H900 | 190,000 psi | 170,000 psi |
| H925 | 170,000 psi | 155,000 psi |
| H1025 | 155,000 psi | 145,000 psi |
| H1075 | 145,000 psi | 125,000 psi |
| H1100 | 140,000 psi | 115,000 psi |
| H1150 | 135,000 psi | 105,000 psi |
Lower temper conditions like H900 deliver the highest strength, while higher temper conditions like H1150 trade some strength for improved toughness and ductility. The right condition depends on your part's load requirements and how it will be used in service.
Why Buy 15-5PH from Tailwind Aerospace Solutions
Tailwind Aerospace Solutions stocks 15-5PH stainless steel to AMS 5659 and AMS 5862 specifications, with full material certifications and traceability documentation on every order. Whether you need round bar, flat bar, sheet, or plate, our team can help confirm the right spec and condition for your application. Contact us today for a quote.
Frequently Asked Questions
15-5PH is a martensitic precipitation-hardening stainless steel (UNS S15500) developed as an improved version of 17-4PH. It offers better transverse toughness, ductility, and more consistent mechanical properties in larger cross sections.
15-5PH was engineered to address limitations in 17-4PH, offering better transverse toughness, improved ductility, and more consistent properties in thicker sections. Both alloys are readily weldable and share a similar chemistry, but 15-5PH generally performs better in larger cross sections.
AMS 5659 is the aerospace material specification covering 15-5PH bar and forgings. It includes two melting practices, with Type 1 covering vacuum melted material and Type 2 covering electroslag remelted (ESR) material.
AMS 5862 is the specification covering 15-5PH sheet, strip, and plate. If your drawing calls for 15-5PH in flat rolled form, this is the applicable spec.
15-5PH is available in round bar, flat bar, square bar, sheet, and plate, along with forgings and other custom shapes on request.
15-5PH is widely used in aerospace for landing gear components, structural fittings, and actuation systems. It is also used in industrial and energy applications including valves, pumps, turbine parts, and nuclear reactor components.
15-5PH can be aged to a range of conditions from H900 to H1150. Lower temperature conditions like H900 produce the highest strength, while higher temperature conditions like H1150 provide improved toughness and ductility at somewhat lower strength.
Yes. All 15-5PH stainless steel supplied by Tailwind Aerospace Solutions includes full material certifications and traceability documentation to support aerospace and defense quality requirements.
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