Stainless Steel Alloy 347H


Type 347H is a high carbon austenitic chromium stainless steel. Found in applications that demand high temperature resistance, other major design features include:

  • Similar resistance and corrosion protection as Alloy 304
  • Used for heavy welded equipment when annealing is not possible
  • Good oxidation resistance, on par with most other austenitic stainless steels
  • Higher carbon allows for better high temperature creep properties

Due to Type 347H unique properties it is used in a variety of application in many of today’s critical industries:

  • Boiler tubes and casings
  • Oil and gas refinery piping
  • Radiant superheaters
  • High-pressure steam pipes
  • Heat exchanger tubes
  • Cabin heaters
  • Heavy wall-welded equipment
  • Aircraft exhaust stacks and collector rings

Along with a higher level of carbon then regular Type 347, Type 347H stainless steel has a unique chemical composition that includes the follow:

  • Fe balance
  • Cr 17-20%
  • Ni 9-13%
  • C 0.04-0.08%
  • Mn 0.5-2.0%
  • S 0.30% max
  • Si 0.75% max
  • P 0.03% max
  • Cb/Ta 1% max