Stainless-Steel-17-7-PH17-7 PH stainless steel is a stable, chromium-nickel-aluminum steel that’s frequently used in the aerospace industry and when meticulous, elaborate parts are needed.

17-7 PH applications include:

  • Springs
  • Washers
  • Blades
  • Fluid seal springs
  • Diaphragms
  • Pressings
  • Flexures
  • Encapsulated bellows

Altemp Alloys offers 17-7 PH stainless steel UNS S17700 in: 

  • Stainless Steel 17-7 PH Plate
    • AMS 5528
  • Stainless Steel 17-7 PH Sheet
    • AMS 5528
    • AMS 5529
  • Stainless Steel 17-7 PH Bar
    • AMS 5644

Chemical Composition

Element Percent by Weight
Type 17-7PH
Carbon 0.09 maximum
Manganese 1.00 maximum
Phosphorus 0.05 maximum
Sulfur 0.03 maximum
Silicon 1.00 maximum
Chromium 16.00 – 18.00
Nickel 6.75 – 7.75
Aluminum 0.75 – 1.50


Resistance to Corrosion

Corrosion resistance of Type 17-7PH stainless steel in all heat treated conditions, like other types of stainless steels – will develop superficial rust in some environments. For example, in a marine atmosphere, stainless steels show evidence of rusting after relatively short exposure periods. However, after exposure of one or two years, the amount of rust present is little more than that present at six months. As with all martensitic steels, 17-7PH stainless steel may be subject to cracking when exposed under stress in environments containing hydrogen sulfide. Such applications are not recommended.