A890 4A

Grade 4A is a duplex stainless steel casting alloy specified by ASTM A890/A890M, developed for pressure-containing parts that demand a balanced combination of corrosion resistance, strength, and toughness. With a composition that includes chromium, nickel, molybdenum, and nitrogen, Grade 4A offers excellent resistance to pitting, crevice corrosion, and chloride stress corrosion cracking in a wide range of service environments. As the cast equivalent of wrought 2205 duplex stainless steel, Grade 4A is widely used in desalination systems, marine components, chemical processing equipment, and pulp and paper applications. It delivers higher mechanical strength than austenitic stainless steels while maintaining good weldability and durability under aggressive conditions.