Stainless Steel 15-5 PH

15-5 stainless steel, otherwise known as UNS S15500, consists of nickel, chromium, and copper and was designed to be a tougher variant of 17-4 stainless steel. It has a martensitic structure in the annealed state, and it is further strengthened by undergoing low-temperature heat treatments, which precipitate copper into the alloy for additional hardness. 

The unique refined structure of 15-5 stainless steel, combined with its inclusion control and decreased amount of delta ferrite, makes it tougher and more corrosion-resistant than 17-4 stainless steel. It is capable of maintaining its high strength, corrosion resistance, and mechanical properties at temperatures up to 600° F. 

15-5 stainless steel can be heat treated at a variety of temperatures and times to achieve various desirable properties and minimize scaling and distortion. By altering the heat treatment temperatures, the material’s strength and ductility can be modified to suit various needs. It can also be cold-worked to improve yield strength. 

Applications of 15-5 Stainless Steel

15-5 Stainless Steel, chemical composition, mechanical properties, & applications

15-5 stainless steel’s good fabrication properties, low-temperature hardening, and excellent corrosion resistance make it a desirable material in a wide range of industries, incl

uding aerospace, chemical and petrochemical, pulp and paper, food processing, and more. Common applications for 15-5 stainless steel include:

  • Hollow shafts
  • Engine parts
  • Sections of marine gas turbine compressors
  • Papermill equipment
  • Gears
  • Aircraft components
  • Nuclear reactor components
  • Fittings and fasteners
  • Valves

Chemical Composition of 15-5 Stainless Steel

The chemical composition of 15-5 stainless steel is as follows:

  • Iron. 75%
  • Chromium. 14.8%
  • Nickel. 4.5%
  • Copper. 3.5%
  • Silicon. 1.0%
  • Manganese. 1.0%
  • Niobium + Tantalum. 0.3%
  • Carbon. 0.070%
  • Phosphorus. 0.040%
  • Sulfur. 0.030%

Mechanical Properties of 15-5 Stainless Steel

There are multiple types, or conditions, of 15-5 stainless steel, each of which has its own unique mechanical properties. These types include:

Solution Treated (A)

  • Tensile strength. 160,000 psi
  • Yield strength. 140,000 psi
  • Elongation. 8%
  • Hardness. C35


  • Tensile strength. 162,000 psi
  • Yield strength. 160,00 psi
  • Elongation. 12%
  • Hardness. C38


  • Tensile strength. 210,000 psi
  • Yield strength. 200,00 psi
  • Elongation. 9%
  • Hardness. C46


What is martensitic stainless steel used for?

Martensitic stainless steel has high strength and hardness in the heat-treated state. It is also magnetic in the hardened and annealed condition, comes in a variety of grades, and offers good workability. Common applications for martensitic stainless steel include cutlery, springs, surgical and dental instruments, pliers, screwdrivers, and more.

What does austenitic stainless steel mean?

Austenitic stainless steel is a type of steel alloy composed of chromium, carbon, nickel, iron, and other minor alloys. This type of steel has excellent corrosion resistance, making it one of the most commonly used stainless steel materials. 

15-5 vs. 17-4 Stainless Steel

Both 15-5 and 17-4 stainless steel are used throughout multiple different industries that require hard stainless steel parts. The key difference between the two alloys is that 15-5 stainless steel is ferrite-free.

Contact Us for Stainless Steel 15-5

Since 1976, Bergsen Metals has been distributing metals to our customers in the machining, aerospace, and automotive industries. With an extensive network of mills, processors, and material suppliers, we can help you find the right stainless steel material for your job requirements. For more information, or to learn more about 15-5 stainless steel, contact us or request a quote today.

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