Alloy 347H (UNS S3409) Applications
Alloy 347/347H stainless steel is common in the petroleum refining industries. Alloy 347/347H stainless steel is used to make radiant superheaters, boiler tubes, high-pressure steam pipes, and general refinery piping. They are also used for heavy-duty exhaust systems and manifolds.
Alloy 347/347H Properties
Alloy 347/347H stainless steel is austenitic stainless steel that contains stabilizing elements. This alloy is easily welded. Annealing may not be required after welding unless stress relief is desired. Alloy 347 stainless steel has excellent resistance to oxidation and corrosion. With high creep strength, Alloy 347 stainless steel works best up to 1600 °F. The addition of columbium plus tantalum in Alloy 347/347H stainless steel gives some desired characteristics like:
- Reduced embrittlement in the HAZ of the weld area
- Prevents harmful carbide precipitation in the heat-affected zone (HAZ) of the weld area
- Imparts substantial immunity to intergranular corrosion