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