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15-5 PH Stainless Steel
NAITE TECH
- Stainless Steel
15-5 PH / UNS S15500 / EN 1.4545
Good
$$$ - High
Mechanical properties depend strongly on aging condition. 15-5 PH offers high strength with good toughness and relatively low heat-treatment distortion, but it is not intended as a specialist chloride- or seawater-resistant grade.
August 2026
Overview
15-5 PH is a martensitic precipitation-hardening stainless steel designated UNS S15500. It combines chromium, nickel and copper alloying with precipitation hardening to achieve high mechanical strength while retaining useful corrosion resistance.
The grade is closely related to 17-4 PH stainless steel, but 15-5 PH was developed to provide a more uniform microstructure and improved transverse toughness and ductility.
15-5 PH is normally solution treated before being aged to a specified condition such as H900, H1025 or H1150. The selected aging condition determines the final balance of:
Strength / Hardness / Toughness / Ductility
This makes the grade particularly useful for highly loaded precision components where both mechanical performance and dimensional control are important.
15-5 PH is commonly selected when a component requires:
High yield and tensile strength
Good toughness
Precipitation-hardening capability
Good dimensional stability during aging
Useful corrosion resistance
Precision machining
High mechanical reliability
Its main engineering advantage is:
High Strength + Toughness + Controlled Precipitation Hardening
For applications where the highest mechanical properties must be balanced with better transverse toughness, 15-5 PH may be considered alongside 17-4 PH stainless steel.
15-5 PH can develop high yield and tensile strength through precipitation aging.
Mechanical properties depend strongly on the selected condition.
For example:
H900 → Higher Strength and Hardness
H1025 → High Strength with Improved Toughness
H1150 → Lower Strength with Greater Toughness and Ductility
The correct condition should be selected according to the actual component loading and service requirements.
One of the main reasons engineers consider 15-5 PH instead of 17-4 PH stainless steel is its improved toughness and transverse mechanical-property consistency.
This can be valuable for:
Highly Loaded Components / Complex Stress States / Aerospace Parts / Precision Mechanical Components
For a direct comparison, see 15-5 PH vs 17-4 PH Stainless Steel.
Unlike conventional martensitic grades that rely primarily on quenching and tempering, 15-5 PH develops its final properties through controlled aging after solution treatment.
A typical manufacturing sequence is:
Condition A Material → Machining → Aging → Final Finishing
This can provide relatively good dimensional control compared with conventional quench-hardening processes.
15-5 PH provides good general corrosion resistance for many industrial, aerospace and mechanical applications.
Its corrosion behavior is often comparable to other precipitation-hardening stainless steels such as 17-4 PH stainless steel.
However, it should not automatically be selected for severe chloride or seawater service.
Where chloride resistance is the primary requirement, 316L stainless steel or 2205 duplex stainless steel may provide a better material direction.
15-5 PH is magnetic.
Its martensitic matrix produces a clear magnetic response in both solution-treated and aged conditions.
This is normal for precipitation-hardening stainless steel.
Because the final strengthening step is precipitation aging rather than a conventional high-temperature quench-hardening cycle, 15-5 PH can provide relatively good dimensional stability during final heat treatment.
This is particularly useful for precision components where:
Strength + Tight Geometry + Post-Machining Heat Treatment
must be combined.
Final dimensional change still depends on part geometry, prior machining stress, section thickness and aging condition.
15-5 PH is commonly used for highly loaded machined and forged components such as:
Shafts / Fasteners / Gears / Valve Components / Pump Parts / Structural Fittings / Aerospace Components / Precision Mechanical Parts
It is particularly useful where high strength is needed without moving to a low-corrosion tool steel or conventional high-strength alloy steel.
For production-focused information, see 15-5 PH Stainless Steel Parts Manufacturing.
15-5 PH and 17-4 PH stainless steel are closely related precipitation-hardening grades.
15-5 PH Stainless Steel
Improved Transverse Toughness
More Uniform Mechanical Behavior
High Strength
Precision High-Load Components
17-4 PH Stainless Steel
Very Widely Available
High Strength
Broad Industrial Use
Established PH Stainless Option
The main selection question is usually not which grade is universally “better,” but whether the application benefits from the toughness and transverse-property advantages associated with 15-5 PH.
For a detailed comparison, see 15-5 PH vs 17-4 PH Stainless Steel.
15-5 PH is a precipitation-hardening stainless steel used where high strength, good toughness, useful corrosion resistance and controlled heat-treatment response are required in the same precision component.
Properties
15-5 PH stainless steel develops its final mechanical properties through precipitation aging. Strength, hardness, toughness and ductility therefore depend strongly on the selected heat-treatment condition.
15-5 PH is a chromium-nickel-copper precipitation-hardening stainless steel. Copper supports precipitation hardening, while niobium and tantalum contribute to the strengthening response.
Representative composition for UNS S15500:
Element | Typical Specification Range |
|---|---|
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% |
Carbon (C) | ≤ 0.07% |
Manganese (Mn) | ≤ 1.00% |
Silicon (Si) | ≤ 1.00% |
Phosphorus (P) | ≤ 0.040% |
Sulfur (S) | ≤ 0.030% |
Iron (Fe) | Balance |
Exact chemistry should be confirmed against the applicable material specification and Mill Test Report.
15-5 PH mechanical properties vary substantially with aging condition.
Representative room-temperature properties are shown below for common conditions.
Condition | Tensile Strength | Yield Strength | Elongation |
|---|---|---|---|
H900 | ≥ 1310 MPa | ≥ 1170 MPa | ≥ 10% |
H1025 | ≥ 1070 MPa | ≥ 1000 MPa | ≥ 12% |
H1075 | ≥ 1000 MPa | ≥ 860 MPa | ≥ 13% |
H1100 | ≥ 965 MPa | ≥ 795 MPa | ≥ 14% |
H1150 | ≥ 930 MPa | ≥ 725 MPa | ≥ 16% |
These values are representative and may vary with product form, section size and governing specification.
The overall trend is:
Lower Aging Temperature → Higher Strength and Hardness
Higher Aging Temperature → Lower Strength but Better Toughness and Ductility
For another high-strength precipitation-hardening option, see 17-4 PH stainless steel.
The selected aging condition is one of the most important design decisions for 15-5 PH.
H900
Highest strength and hardness among the commonly used conditions.
Best suited where maximum mechanical strength is the priority and lower toughness is acceptable.
H1025
Maintains high strength while providing a more balanced combination of toughness and ductility.
Often useful for highly loaded precision mechanical components.
H1075 / H1100
Provide a progressively greater emphasis on toughness and ductility with lower strength than H900.
H1150
Provides lower strength but improved toughness and ductility.
It may be preferred when maximum strength is not required and a tougher condition is more important.
The correct condition should be specified on the drawing or purchasing requirement rather than simply calling out “15-5 PH.”
For a detailed comparison of precipitation-hardening grades, see 15-5 PH vs 17-4 PH Stainless Steel.
Property | Approximate Value |
|---|---|
Density | 7.8 g/cm³ |
Elastic Modulus | Approx. 197 GPa |
Thermal Conductivity | Approx. 18 W/m·K |
Specific Heat | Approx. 460 J/kg·K |
Electrical Resistivity | Approx. 0.75 µΩ·m |
Thermal Expansion | Approx. 10.8 × 10⁻⁶ /K |
Magnetic | Yes |
Physical-property values are approximate and can vary with temperature and material condition.
15-5 PH provides good general corrosion resistance for many aerospace, industrial and mechanical applications.
Its corrosion behavior is broadly similar to other precipitation-hardening stainless grades such as 17-4 PH stainless steel.
It performs well in many:
Atmospheric / Freshwater / Mild Industrial / General Mechanical Environments
However, 15-5 PH is not primarily selected for severe chloride exposure or direct seawater service.
For applications where chloride resistance is the dominant requirement, consider 316L stainless steel or 2205 duplex stainless steel.
Environment | General Suitability |
|---|---|
Dry Indoor Service | Excellent |
Atmospheric Exposure | Good |
Freshwater | Good |
Mild Industrial Environment | Good |
Coastal Exposure | Application Dependent |
Chloride Process Environment | Evaluate Carefully |
Direct Seawater | Not Preferred |
Aggressive Chemical Service | Material Review Required |
Actual performance depends on temperature, chloride concentration, surface condition, crevices and stress state.
15-5 PH develops its final strength through solution treatment followed by precipitation aging.
A common manufacturing route is:
Condition A → Machining → Aging → Final Inspection / Finishing
Solution Treatment
A representative solution-treatment temperature is approximately:
1038°C / 1900°F
followed by cooling according to the applicable specification.
This produces the solution-treated Condition A used before final aging.
Precipitation Aging
Common aging cycles include approximately:
Condition | Aging Temperature | Typical Time |
|---|---|---|
H900 | 482°C / 900°F | 1 hour |
H925 | 496°C / 925°F | 4 hours |
H1025 | 552°C / 1025°F | 4 hours |
H1075 | 580°C / 1075°F | 4 hours |
H1100 | 593°C / 1100°F | 4 hours |
H1150 | 621°C / 1150°F | 4 hours |
Exact time, temperature and cooling requirements should follow the governing material or heat-treatment specification.
15-5 PH is often selected for precision components because precipitation aging can provide relatively controlled dimensional behavior compared with conventional quench-hardening processes.
This is particularly useful for:
Precision Shafts / Aerospace Components / Valve Parts / Mechanical Fittings / Tight-Tolerance Machined Parts
However, dimensional stability should not be treated as zero distortion.
Final dimensional change can still be affected by:
Part Geometry / Residual Machining Stress / Section Thickness / Aging Condition / Prior Material Condition
For very tight tolerances, final grinding or finish machining may still be required after aging.
15-5 PH can develop high hardness after precipitation aging, particularly in lower-temperature conditions such as H900.
This gives the grade useful resistance to mechanical loading and moderate wear.
However, 15-5 PH is primarily a:
High-Strength Structural Stainless Steel
rather than a dedicated wear-resistant or bearing-grade stainless steel.
Where maximum hardness and wear resistance are the dominant requirements, 420 stainless steel or 440C Stainless Steel may be more appropriate.
15-5 PH is magnetic.
Its martensitic matrix produces a clear magnetic response in both solution-treated and precipitation-aged conditions.
This distinguishes it from fully austenitic grades such as 316L stainless steel, although cold-worked austenitic stainless steels may also develop some magnetic response.
Common material designations include:
System | Designation |
|---|---|
Grade | 15-5 PH |
UNS | S15500 |
EN Material Number | 1.4545 |
EN Designation | X5CrNiCu15-5 |
EN 1.4545 is commonly associated with 15-5 PH, but exact equivalence should be verified against the applicable product specification.
Common Specifications
ASTM A564 / A564M
Commonly used for precipitation-hardening stainless steel bars and shapes.
ASTM A693 / A693M
Relevant to precipitation-hardening stainless steel plate, sheet and strip.
ASTM A705 / A705M
Relevant to age-hardening stainless steel forgings.
AMS 5659
Commonly associated with 15-5 PH bar, forging and related aerospace product forms.
AMS 5862
Commonly associated with 15-5 PH sheet, strip and plate.
The exact standard should match the product form and project requirement.
15-5 PH is commonly available as:
Round Bar / Forged Bar / Plate / Sheet / Billet / Forged Stock
Round bar and forged stock are especially relevant for high-strength precision machined components.
For manufacturing-focused information, see 15-5 PH Stainless Steel Parts Manufacturing.
15-5 PH is best understood as:
High Strength + Good Toughness + Precipitation Hardening + Good Dimensional Stability
Its final properties depend strongly on aging condition.
For nearby material choices:
17-4 PH Stainless Steel → Closely related, widely used PH grade
316L Stainless Steel → Better choice when chloride corrosion dominates
2205 Duplex Stainless Steel → High strength combined with stronger chloride resistance
420 Stainless Steel → Higher hardness and wear focus
440C Stainless Steel → Maximum hardness and bearing-type applications
Manufacturing
15-5 PH stainless steel is well suited to precision machining, forging and controlled fabrication. Its precipitation-hardening response allows components to be machined in a softer condition and subsequently aged to achieve the required strength and hardness.
Manufacturing Process | Compatibility |
|---|---|
CNC Machining | ✅ |
CNC Turning | ✅ |
Milling | ✅ |
Drilling | ✅ |
Grinding | ✅ |
Forging | ✅ |
Sheet Metal Processing | ✅* |
Laser Cutting | ✅* |
Forming / Bending | ✅* |
Welding | ✅* |
Heat Treatment | ✅ |
Stamping | —* |
Deep Drawing | —* |
Brazing | —* |
Metal 3D Printing | —* |
Casting | — |
* Suitability depends strongly on material condition, section thickness, final heat treatment and qualification requirements.
15-5 PH is primarily used as a machined or forged high-strength stainless steel, rather than as a general-purpose deep-drawing or sheet-forming grade.
15-5 PH can be machined successfully using conventional CNC turning, milling and drilling processes.
Machining is generally performed before final precipitation aging when possible, because the solution-treated condition is easier to machine than the higher-strength aged conditions.
Typical machining operations include:
CNC Turning / Milling / Drilling / Boring / Threading / Reaming
Important machining considerations include:
Rigid workholding
Sharp cutting tools
Stable cutting engagement
Effective coolant
Controlled heat generation
Allowance for final finishing after aging where required
Compared with 17-4 PH stainless steel, machining behavior is broadly similar because both are precipitation-hardening stainless grades.
For production-focused information, see 15-5 PH Stainless Steel Parts Manufacturing.
Heat treatment is central to 15-5 PH manufacturing.
The material is typically machined in Condition A and then precipitation aged to achieve the required final strength, hardness and toughness.
A common manufacturing route is:
Condition A Material → CNC Machining → Aging → Final Inspection → Finish Grinding if Required
The selected aging condition should be defined before production because it directly affects:
Strength / Hardness / Toughness / Ductility / Dimensional Change
Typical conditions include:
H900 / H925 / H1025 / H1075 / H1100 / H1150
Lower-temperature aging generally retains higher strength and hardness, while higher-temperature aging provides greater toughness and ductility.
15-5 PH is often chosen for precision components because precipitation aging generally produces less severe distortion than conventional quench-hardening processes.
However, dimensional change should still be considered for:
Long shafts
Thin sections
Asymmetrical parts
Tight concentricity requirements
Precision bores
Components with large section changes
For critical dimensions, the manufacturing plan may include:
Semi-Finish Machining → Aging → Finish Grinding or Final Machining
This approach helps maintain final dimensional accuracy.
Grinding is useful when aged 15-5 PH components require tighter tolerances or improved surface finish.
Typical applications include:
Bearing Surfaces / Shaft Diameters / Sealing Surfaces / Precision Fits / Hardened Functional Features
Finish grinding can be especially valuable after H900 or other higher-strength aging conditions.
Where maximum hardness and wear resistance are the dominant design requirements, 420 stainless steel or 440C Stainless Steel may provide a more suitable material direction.
15-5 PH can be welded, but welding should be treated as part of the final heat-treatment plan rather than as an isolated fabrication step.
Important considerations include:
Base-material condition
Welding process
Filler selection
Heat input
Joint design
Post-weld heat treatment
Final mechanical-property requirement
Where maximum and uniform mechanical properties are important, post-weld solution treatment and aging may be required depending on the project specification.
15-5 PH should not be treated as a general welded-fabrication grade in the same way as 304L stainless steel or 316L stainless steel.
15-5 PH can be formed in the solution-treated condition, but formability decreases substantially after aging.
For this reason, forming operations are normally completed before final precipitation hardening.
Important factors include:
Material Condition / Bend Radius / Thickness / Springback / Tooling Capacity
For highly complex sheet forming or deep drawing, 304L stainless steel or 316L stainless steel generally offers better fabrication flexibility.
15-5 PH is available in forged forms and is commonly used for high-strength structural and mechanical components.
Forging may be suitable for:
Shafts / Fittings / Structural Components / Aerospace Hardware / High-Load Mechanical Parts
Forged material normally requires controlled solution treatment and aging to develop the required final properties.
The applicable forging specification should match the product form and engineering requirement.
15-5 PH sheet and plate can be laser cut and fabricated before final aging where the product form and specification permit.
However, it is not primarily selected for high-volume sheet-metal forming.
Its strongest manufacturing use remains:
Machined / Forged / High-Strength Precision Components
rather than conventional sheet-metal enclosures or deep-drawn parts.
15-5 PH components can receive a range of mechanical and chemical finishing processes.
Typical options include:
Machined Finish / Grinding / Polishing / Passivation / Bead Blasting / Laser Marking
Machined Finish
Suitable for general mechanical components where the as-machined surface meets dimensional and functional requirements.
Grinding
Useful after aging for precision dimensions and functional surfaces.
Polishing
Can reduce surface roughness and improve appearance.
Passivation
May be used after machining, grinding or fabrication to remove free iron contamination and support a clean stainless surface.
Surface-treatment requirements should be defined according to the operating environment and final component function.
For controlled 15-5 PH components, material identity and heat-treatment condition are both important.
Typical documentation may include:
Material Grade Verification / Mill Test Report / Heat Number / Heat-Treatment Certification / Hardness Results / Dimensional Inspection
Where required, additional testing should be agreed before production.
Material documentation should confirm the specified grade:
15-5 PH / UNS S15500
The Mill Test Report should be reviewed for the applicable:
Heat number
Chemical composition
Material specification
Product form
Material condition
The material should not be accepted solely because it is described commercially as “15-5 PH.”
Because final performance depends strongly on aging condition, the required condition should be clearly defined.
For example:
UNS S15500 / H900
or
UNS S15500 / H1025
Where required, heat-treatment documentation may include:
Aging Condition / Treatment Temperature / Batch Identification / Hardness Result
Positive Material Identification may be considered where additional alloy verification is required.
PMI requirements and acceptance criteria should be agreed before production.
PMI does not by itself confirm:
Aging Condition / Mechanical Properties / Hardness / Complete Heat-Treatment History
Material certification and heat-treatment records remain important.
15-5 PH is best suited to manufacturing routes centered on:
Machining or Forging → Controlled Aging → Final Finishing
Its strongest manufacturing characteristics are:
High Strength / Good Machinability / Precipitation Hardening / Good Dimensional Stability
Its main limitations are:
Condition-Dependent Properties / Reduced Formability After Aging / More Heat-Treatment Control Than Austenitic Stainless Steel
For nearby manufacturing choices:
17-4 PH Stainless Steel → Closely related high-strength PH grade
420 Stainless Steel → Higher hardness and wear emphasis
316L Stainless Steel → Better fabrication and chloride-corrosion focus
2205 Duplex Stainless Steel → High strength combined with stronger chloride resistance
15-5 PH Stainless Steel Parts Manufacturing → Future manufacturing-focused page
Selection
15-5 PH stainless steel is selected for high-strength precision components where mechanical reliability, toughness and controlled precipitation hardening are more important than maximum formability or severe chloride resistance.
15-5 PH is commonly used for:
Aerospace Components / Shafts / Fasteners / Valve Components / Pump Parts / Structural Fittings / Gears / Precision Mechanical Parts / High-Load Machined Components
Aerospace & Structural Components
15-5 PH is widely considered for highly loaded components where high strength, toughness and consistent mechanical properties are required.
Typical examples include:
Structural Fittings / Actuation Components / Precision Hardware / High-Load Mechanical Parts
For applications requiring a closely related and more widely used precipitation-hardening grade, see 17-4 PH stainless steel.
Shafts & Rotating Components
15-5 PH is suitable for shafts and rotating components requiring:
High Yield Strength / Good Toughness / Precision Machining / Controlled Final Heat Treatment
Finish grinding may be used after aging where tight dimensional tolerances are required.
Fasteners & Precision Hardware
High-strength fasteners, studs and precision hardware can benefit from the combination of machinability and precipitation-hardening capability.
The required aging condition should be defined according to the final strength and toughness requirement.
Valve & Pump Components
15-5 PH may be considered for selected:
Valve Stems / Shafts / Fittings / Pump Components / Mechanical Internals
where high mechanical strength is required together with useful general corrosion resistance.
For chloride-rich process environments, 316L stainless steel or 2205 duplex stainless steel may provide a better corrosion-resistance direction.
For manufacturing-focused information, see 15-5 PH Stainless Steel Parts Manufacturing.
Choose 15-5 PH when the application requires:
High yield and tensile strength
Good toughness
Controlled precipitation hardening
Good dimensional stability during aging
Precision machining
Magnetic material behavior
Good general corrosion resistance
Reliable properties in highly loaded mechanical components
15-5 PH is particularly useful when both high strength and toughness are required in the same component.
15-5 PH is closely related to 17-4 PH stainless steel, but it is often considered when improved transverse toughness and more uniform mechanical behavior are desirable.
This can be valuable for components exposed to:
Complex Loading / Multidirectional Stress / Shock or Impact / High Mechanical Demand
The actual benefit depends on product form, heat treatment and applicable specification.
Different aging conditions allow the material-property balance to be adjusted.
H900
Higher strength and hardness.
H1025
High strength with a more balanced toughness profile.
H1075 / H1100
Greater emphasis on toughness and ductility.
H1150
Lower strength with improved toughness.
This flexibility allows the same alloy family to support different mechanical design requirements.
15-5 PH should not be selected solely because high strength is required.
Another stainless grade may provide a better balance when corrosion, fabrication, wear or cost dominates the application.
Main Requirement | Grade to Consider | Selection Reason |
|---|---|---|
Widely Used PH Stainless + High Strength | 17-4 PH Stainless Steel | Broad availability and established industrial use |
Better Chloride Corrosion Resistance | Better chloride-focused corrosion performance | |
High Strength + Stronger Chloride Resistance | 2205 Duplex Stainless Steel | Duplex strength with improved chloride resistance |
Higher Hardness & Wear Resistance | Hardness-focused martensitic grade | |
Maximum Hardness / Bearing Applications | 440C Stainless Steel | Higher-carbon wear and bearing grade |
Extensive Forming & Welding | 304L Stainless Steel | Better fabrication flexibility |
Free-Machining Productivity | 416 Stainless Steel | Machining-focused martensitic grade |
This is the most important comparison for 15-5 PH.
Both grades are precipitation-hardening stainless steels capable of developing high mechanical strength through aging.
15-5 PH
Improved Transverse Toughness
More Uniform Mechanical Behavior
High Strength
Precision High-Load Components
17-4 PH
High Strength
Broad Industrial Use
Wide Availability
Extensive Manufacturing History
The two grades share similar heat-treatment concepts, but they should not be treated as automatically interchangeable.
Choose 15-5 PH when toughness consistency and demanding multidirectional loading are particularly important.
Choose 17-4 PH stainless steel when its established availability and property balance meet the application requirements.
For a detailed comparison, see 15-5 PH vs 17-4 PH Stainless Steel.
15-5 PH and 316L stainless steel serve very different engineering purposes.
15-5 PH
High Strength
Precipitation Hardening
Magnetic
Precision Structural Components
316L
Lower Strength
Excellent Weldability
Excellent Formability
Better Chloride Corrosion Resistance
Choose 15-5 PH when mechanical strength dominates.
Choose 316L when corrosion resistance, welding and fabrication flexibility dominate.
For a detailed comparison, see 15-5 PH vs 316L Stainless Steel.
Both materials can provide substantially higher strength than conventional austenitic stainless steels, but their selection logic is different.
2205 duplex stainless steel combines high strength with stronger resistance to chloride-induced pitting, crevice corrosion and stress-corrosion cracking.
15-5 PH develops high mechanical strength through precipitation aging and is often selected for precision structural and mechanical components.
Choose 15-5 PH for:
High mechanical strength
Precision heat-treated components
Good toughness
Controlled aging response
Choose 2205 for:
High strength
Chloride resistance
Process equipment
Piping and corrosion-critical applications
For a detailed comparison, see 15-5 PH vs 2205 Duplex Stainless Steel.
420 stainless steel is primarily selected for hardness and wear resistance.
15-5 PH is primarily selected for high structural strength and toughness.
15-5 PH
High Strength
Good Toughness
Precipitation Hardening
Better Structural Property Balance
420
Higher Hardness Potential
Better Wear Resistance
Martensitic Hardening
Wear-Focused Mechanical Parts
Choose 15-5 PH when structural strength and toughness are more important.
Choose 420 when hardness and wear dominate.
For a detailed comparison, see 15-5 PH vs 420 Stainless Steel.
416 stainless steel is designed primarily for machining productivity.
15-5 PH is designed primarily for high mechanical performance.
416
Excellent Machinability
Good Chip Control
Heat-Treatable
Moderate Strength
15-5 PH
Higher Strength
Better Toughness
Precipitation Hardening
High-Load Components
Choose 416 when machining efficiency is the primary requirement.
Choose 15-5 PH when final mechanical performance is more important than maximum machining productivity.
For a detailed comparison, see 416 vs 15-5 PH Stainless Steel.
15-5 PH is a strong candidate for:
Aerospace Components / High-Strength Shafts / Structural Fittings / Fasteners / Valve Parts / Pump Components / Precision Mechanical Parts
Its core selection advantage is:
High Strength + Good Toughness + Controlled Precipitation Hardening
Consider nearby grades when:
17-4 PH Stainless Steel → Closely related, widely used PH stainless steel
2205 Duplex Stainless Steel → High strength with stronger chloride resistance
316L Stainless Steel → Better welding, forming and chloride corrosion resistance
420 Stainless Steel → Higher hardness and wear resistance
416 Stainless Steel → Better machining productivity
440C Stainless Steel → Higher hardness and bearing-type applications
Choose 15-5 PH when high mechanical strength must be combined with good toughness, controlled heat-treatment response and precision dimensional requirements.
If severe chloride corrosion, extensive welding, maximum hardness or machining productivity is the dominant requirement, another stainless steel grade will usually provide a more appropriate property balance.
FAQs
Common engineering questions about 15-5 PH stainless steel strength, aging conditions, heat treatment, corrosion resistance, machining, toughness and material selection.
15-5 PH is a precipitation-hardening stainless steel designated UNS S15500. It combines high mechanical strength, good toughness and useful corrosion resistance with a controlled aging response.
It is commonly used for highly loaded precision components, aerospace hardware, shafts, fasteners and valve components.
The name refers approximately to the alloy's chromium and nickel content, while “PH” means precipitation hardening.
Copper-containing precipitates formed during aging help develop the material's high strength and hardness.
Yes. Properly aged 15-5 PH can develop substantially higher yield and tensile strength than annealed 304 stainless steel or 316L stainless steel.
However, 304 and 316L provide much greater formability and are generally better choices for extensive welded fabrication.
Both are high-strength precipitation-hardening stainless steels. 15-5 PH is often considered where improved transverse toughness and more uniform mechanical behavior are important.
17-4 PH stainless steel remains a widely used PH grade with broad industrial availability.
15-5 PH vs 17-4 PH Stainless Steel
Yes. Heat treatment is essential to the final properties of 15-5 PH.
The material is typically solution treated to Condition A and then precipitation aged to a specified condition such as H900, H1025 or H1150.
These designations identify precipitation-aging conditions based primarily on aging temperature.
H900 generally provides higher strength and hardness, while higher-temperature conditions such as H1150 provide lower strength with improved toughness and ductility.
H900 is commonly used where maximum strength and hardness are the priority.
The required condition should still be selected according to toughness, ductility, corrosion behavior and the applicable material specification.
Higher-temperature aging conditions such as H1100 or H1150 generally provide improved toughness and ductility compared with H900.
This occurs at the expense of some strength and hardness.
Yes. 15-5 PH provides good general corrosion resistance for many atmospheric, freshwater, aerospace and industrial applications.
It is not primarily designed for severe chloride or direct seawater service.
15-5 PH is not normally the first choice for continuous direct seawater exposure or severe chloride environments.
Where chloride resistance is the primary requirement, 316L stainless steel or 2205 duplex stainless steel should also be evaluated.
Yes. 15-5 PH is magnetic because its matrix is primarily martensitic after solution treatment and aging.
Magnetic response is normal for this precipitation-hardening grade.
Yes. 15-5 PH can be successfully turned, milled, drilled and threaded using conventional CNC machining methods.
Machining is generally easier before final aging because the solution-treated condition has lower strength than the fully aged condition.
Most material removal is commonly completed before final aging.
A typical route is: Condition A → Machining → Aging → Final Grinding or Inspection
Tight-tolerance components may require final grinding or finish machining after aging.
Precipitation aging generally produces relatively controlled dimensional change compared with conventional quench-hardening processes.
Distortion can still occur because of part geometry, residual machining stress, section thickness and heat-treatment condition.
Yes, 15-5 PH can be welded using appropriate procedures.
Welding should be considered together with the required final heat-treatment condition because the thermal cycle can affect microstructure and mechanical properties.
For fabrication-intensive welded structures, 304L stainless steel or 316L stainless steel may provide simpler fabrication.
15-5 PH can provide useful hardness and moderate wear resistance, particularly in higher-strength aging conditions.
However, it is primarily a high-strength structural stainless steel rather than a dedicated wear grade.
For higher hardness and wear resistance, consider 420 stainless steel or 440C Stainless Steel.
Typical components include shafts, high-strength fasteners, structural fittings, valve parts, pump components, aerospace hardware and precision mechanical components.
15-5 PH Stainless Steel Parts Manufacturing
Widely Used High-Strength PH Grade → 17-4 PH Stainless Steel
Better Chloride Corrosion Resistance → 316L Stainless Steel
High Strength + Chloride Resistance → 2205 Duplex Stainless Steel
Higher Hardness & Wear Resistance → 420 Stainless Steel
Maximum Machining Productivity → 416 Stainless Steel
Maximum Hardness / Bearing Applications → 440C Stainless Steel
If you are evaluating 15-5 PH stainless steel for a high-strength precision component, share your drawing, required aging condition, mechanical requirements and operating environment. We can help review whether 15-5 PH provides the right balance of strength, toughness, dimensional stability and corrosion resistance for your application.
