Springs are a common solution in many modern products, from the high-strength performance requirements of agricultural equipment and transportation, to the corrosion-resistant demands of the mining and nuclear industries. This creates engineering challenges for manufacturers, and Central Wire has the products to solve these problems.

Among our stock of stainless steel metals, one option is the 17-7 PH® alloy.

Stainless Spring WireThis wire is a popular choice for spring wire consumers in the United Kingdom and internationally. At a glance, this material offers the following properties:

  • 17-7PH, type 631 or UNSA S17700, is a chromium-nickel-aluminum precipitation hardening stainless steel. It’s an ideal alloy for applications that require good formability, high strength/hardness, good corrosion resistance and minimum distortion upon heat treating.
  • The alloy offers corrosion resistance comparable to 302, but it can achieve higher strength after precipitation hardening due to aluminum additions.
  • The alloy also provides excellent properties for flat springs at temperatures up to 315°C (600°F).
  • This alloy meets the following industry specifications: ASTM A313, EN 10270-3, ISO 6931, and AMS 5678G specifications.
  • CWI UK can supply 17-7 PH® for sizes from 0.80mm up to 19mm in diameter.
  • Chemical composition: Al: 0.75-1.50, Cr: 16.0-18.0, and Ni: 6.5-7.75.

The chemical composition of this alloy specifies: Al: 0.75-1.50, Cr: 16.0-18.0, and Ni: 6.5-7.75. 17-7PH® begins as an austenitic structure in the solution treated stage. 

Through strain and coldwork during the wire-drawing process, the material transforms to a martensitic structure that is finally further strengthened through the aging process which forms submicroscopic NiAl (NiAl and Ni3Al) based precipitates increasing the material hardness and strength.

When creating a spring, the wire’s success in your application is dependent on its strength and corrosion resistance. The 17/7 alloy is used commonly in automotive, aerospace, chemical processing equipment, oil and petroleum refining equipment and food processing equipment.

Interested in learning more about our alloys? Review our stainless steel grades chart. Contact a member of our sales department to learn more about how the 17-7 alloy can work for your spring application. Finally, check out our spring wire catalog.