Stainless Steel Alloy 347H

Description

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’s unique properties, it is used in a variety of applications 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 than regular Type 347, Type 347H stainless steel has a unique chemical composition that includes the following:

• 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