ASTM A 265, B 366, B 463
B 464, B 471, B 472, B 473
B 474, B 475
Other common names: Carpenter 20, 20Cb-3®, Incoloy® alloy 20
Alloy 20, also known as Carpenter 20, is a nickel-iron-chromium austenitic alloy that was developed for maximum resistance to acid attack, specifically sulfuric acid. This superalloy has excellent resistance to general corrosion, pitting, and crevice corrosion in chemicals containing chlorides and sulfuric, phosphoric, and nitric acids. It also contains niobium for stabilization against sensitization and resultant intergranular corrosion. Carpenter 20 combines excellent corrosion resistance with elevated mechanical properties and relatively easy fabrication. Although originally designed for use in sulfuric acid related industries, Alloy 20 is now a popular choice for a wide variety of industries including the chemical, food, pharmaceutical, and plastics industries. In addition, this superalloy is used in heat exchangers, mixing tanks, metal cleaning and pickling equipment, and piping.
Excellent general corrosion resistance to sulfuric acid
Excellent resistance to chloride stress corrosion cracking
Excellent mechanical properties and fabricability
Minimal carbide precipitation during welding
Excels in resisting corrosion to hot sulfuric acids
Chemical Composition, %
Synthetic rubber manufacturing equipment
Processing of pharmaceuticals, plastics and organic and heavy chemicals
Tanks, piping, heat exchangers, pumps, valves, and other process equipment
Acid cleaning and pickling equipment
Chemical process piping, reactor vessels
Petrochemical process equipment
Food and dye production
Yield Min. (.2% offset)
Reduction of Area Min.
Bar (hot or cold finished)
*Incoloy® is a registered trademark of Special Metals Corporation group of Companies.