A precipitation hardenable chromium-nickel-copper grade, Alloy 17-4 offers excellent corrosion resistance, high creep rupture strength and high tensile strength.

Most commonly used in the oil and gas, aerospace and motorsport markets, Alloy 17-4 offers excellent corrosion resistance, high creep rupture strength, high tensile strength and hardness.

  • UNS Number: S17400
  • Werkstoff Number: 1.4542, 1.4548
  • ASTM: A693, A564, A705, 5622, 5643, 5825
  • AMS: 5604

Product availability

Round Bar

Chemical analysis

Min315--3--5 x c---


  • Gate valves
  • Pump shafts, gears and plungers
  • Valve stems, balls, bushings and seats
  • Fasteners

About Alloy 17-4

Alloy 17-4 is an age-hardening martensitic stainless combining high strength with the corrosion resistance of stainless steel.

The alloy maintains high tensile strength and hardness up to 316°C and excellent oxidation resistance up to 593°C. Alloy 17-4 has good creep-stress rupture properties up to 482°C.

Hardening is achieved by a short-time, simple low-temperature treatments. Unlike conventional martensitic stainless steels, such as type 410, Alloy 17-4 is more weldable.

The strength, corrosion resistance and simplified fabrication can make Alloy 17-4 stainless a cost-effective replacement for high strength carbon steels as well as other stainless grades.

For more information on 17-4 Stainless, or to enquire about our inventory then please contact us, alternatively fill in our online quote form and we’ll get right back to you.

  • Density: 7.81 g/cm³
  • Poisson's ratio : 0.272
  • Melting range: 1404.4 – 1440.6 °C
  • Electrical resistivity: 7.7 x 10^-7 Ωm

Mechanical & Physical Properties

Mechanical & Physical Properties21°C100°C200°C300°C
Coefficient of Thermal Expansion µm/m⁰C1313.514
Thermal Conductivity/kcal/(hr.m.°C)12.813.714.615.5
Modulus of Elasticity/ x105 MPa21.941.861.8

Representative Tensile Properties, Longitudinal Direction

Ultimate Tensile Strength, ksi200190170165150145 125
0.2% Yield Strength, ksi18517516515013512585
Elongation % in 2″ or 4XD14141516171922
Reduction of Area, %50545658586068
Hardness, Brinell (Rockwell)420 (C44)409 (C42)352 (C38)341 (C35)332 (C35)311 (C33)277 (C27)
Impact Charpy V-Notch, ft – lbs152535402530100
Proud members of the British Valve & Actuator AssociationProud members of the British Valve & Actuator Association