15-5 PH Stainless Steel – CNC Machining

15-5 PH stainless steel is selected for CNC machined components requiring high strength, good toughness, and consistent dimensional response.

Its precipitation-hardening behavior and refined microstructure directly influence cutting forces, tool wear, and surface integrity.

At ShvaveyMetal, 15-5 PH CNC machining strategies are defined around material condition, heat treatment sequence, and process stability.

15-5 PH is a martensitic precipitation-hardening stainless steel developed as an evolution of 17-4 PH with improved transverse toughness.

It is supplied in solution-annealed and aged conditions, allowing mechanical properties to be tailored after machining.

Mechanical Properties (Typical – H1025 Condition)

Property Typical Value Units
Density ~7.75 g/cm³
Yield Strength ~1,050 MPa
Ultimate Tensile Strength ~1,170 MPa
Elongation at Break ~12 %
Elastic Modulus ~200 GPa
Hardness ~35 HRC

Values vary depending on heat treatment condition and applicable standards.

Thermal & Physical Properties

Property Typical Value Units
Thermal Conductivity ~18 W/m·K
Coefficient of Thermal Expansion ~10.8 µm/m·K
Melting Range ~1,400–1,450 °C

These properties affect heat dissipation and dimensional behavior during CNC machining.

Chemical Composition (Representative)

Element Typical Content (%)
Iron (Fe) Balance
Chromium (Cr) 14.0 – 15.5
Nickel (Ni) 3.5 – 5.5
Copper (Cu) 2.5 – 4.5
Manganese (Mn) ≤ 1.0
Silicon (Si) ≤ 1.0
Carbon (C) ≤ 0.07

Composition ranges depend on material standards and supplier certification.

15-5 PH stainless steel machining behavior is strongly influenced by its heat treatment condition.

Key machining characteristics include:

  • Moderate cutting forces in solution-annealed condition
  • Improved machinability compared to 17-4 PH in aged states
  • Predictable chip formation with appropriate tooling
  • Increased tool wear as hardness increases after aging

Machining is typically performed prior to final aging to support productivity and dimensional control.

Benefit Description
Balanced Strength and Toughness Suitable for highly stressed components
Dimensional Stability Predictable response during aging
Corrosion Resistance Performs well in industrial environments
Improved Toughness Enhanced transverse properties
Process Consistency Stable machining behavior under controlled parameters

15-5 PH stainless steel is commonly used for CNC machined components such as:

  • Shafts, pins, and load-bearing parts
  • Precision mechanical assemblies
  • High-strength corrosion-resistant components

Application suitability depends on loading conditions and final heat treatment.

Condition General Characteristics
Solution Annealed (A) Maximum machinability prior to aging
H900 Maximum strength
H1025 Balanced strength and toughness
H1100 Improved toughness with reduced strength

Final mechanical properties are achieved through controlled aging after machining.

When designing CNC machined parts from 15-5 PH stainless steel, consideration should be given to:

  • Machining prior to aging where possible
  • Allowance for dimensional change during heat treatment
  • Conservative tooling strategies in hardened conditions
  • Clear definition of final mechanical requirements

Early coordination between design, machining, and heat treatment supports stable production.

FAQ

What is the machinability of 15-5 PH in the H1025 condition?

In H1025 the material is aged to roughly 35 HRC, giving moderate machinability, harder than Condition A but considerably more workable than H900. Carbide tooling, reduced surface speeds, rigid setups and consistent feed produce stable results. Many precision components are finish-machined in H1025 to avoid post-ageing movement altogether.

What is the difference between 15-5 PH and 17-4 PH?

Both are precipitation hardening stainless steels reaching similar strength levels. 15-5 PH is vacuum remelted to reduce delta ferrite, giving a cleaner microstructure with better transverse toughness and more uniform properties in heavier sections. 17-4 PH is more widely stocked and often more economical.

Which heat treatment conditions are used for 15-5 PH?

15-5 PH is supplied in Condition A and aged to conditions such as H900, H1025, H1075 or H1150, named for the ageing temperature in Fahrenheit. Lower temperatures deliver higher strength, higher temperatures improve toughness and ductility. The condition defines both properties and machining behaviour.

Should 15-5 PH be machined in Condition A or after ageing?

Both routes are used. Machining in Condition A then ageing is the most productive approach, and dimensional movement during ageing is small and predictable. For tight tolerance features, machining after ageing eliminates residual movement entirely, at the cost of higher tool wear and slower cycle times.

What are machined 15-5 PH components used for?

It is specified for high strength structural fittings, valve and pump parts, shafts and industrial hardware requiring high strength combined with good fracture toughness. It is often selected over 17-4 PH where transverse properties and component reliability are governing design requirements.


Why Machine 15-5 PH Stainless Steel at ShvaveyMetal

ShvaveyMetal applies material-specific CNC machining workflows aligned with material condition, tooling, and inspection requirements.

This approach ensures that CNC machined 15-5 PH stainless steel components meet defined mechanical, dimensional, and performance criteria across prototype and production programs.