Alloy 28 with Excellent Resistance to Reducing and Oxidizing Acids

Alloy 28 (UNS N08028, W. Nr. 1.4563) is a nickel-iron-chromium alloy with additions of molybdenum and copper. It has excellent resistance to both reducing and oxidizing acids, to stress-corrosion cracking, and to localise attack such as pitting and crevice corrosion. The alloy are especially resistant to sulphuric and phosphoric acid. Used for chemical processing, pollution control equipment, oil and gas well piping, nuclear fuel reprocessing, acid production and pickling equipment.

Typical composition

Ni=31, Cr=27, Cu=1.0, Mo=3.5, C≤0.020, Mn≤2.0, P≤0.025, S≤0.015, Si≤0.6, Fe=Rem

Spec

ASTM B668 - 14
Standard Specification for UNS N08028 and N08029 Seamless Pipe and Tube

Advantages

•  Very high corrosion resistance in strong acids
•  Very good resistance to stress corrosion cracking (SCC) and intergranular corrosion in various environments
•  High resistance to pitting and crevice corrosion
•  Good weldability

Applications

•  Phosphoric acid
•  Sulphuric acid
•  Oil and gas
•  Fluoride-bearing media
•  Nuclear power plants
•  Seawater and chloride-bearing cooling water