AM350 is a chromium-molybdenum-nickel stainless steel. It is renowned for its excellent formability and resistance to stress corrosion cracking, making it a popular choice for surgical instruments and other critical components. In addition, its resistance to corrosion, oxidation and carburization make it well-suited for applications in hostile environments such as oil and gas production and other offshore applications.
The composition of AM350 consists of 19−21wt% chromium, 3−4wt% molybdenum and 5−7wt% nickel. The balance of the properties consist of iron, manganese, and trace amounts of carbon and silicon. This results in a stainless steel with excellent mechanical properties as well as outstanding corrosion resistance, particularly in high chloride environments.
AM350 has a BCC crystal lattice structure, with a moderate melting point of about 2580F (1428C). It has been known to retain a good balance of strength, ductility, and formability even at relatively high temperatures. This is due to its exceptional metallurgy, resistance to work hardening, and ability to recover the strain-hardened condition upon cooling. The combination of its strength and ductility make it difficult to machine using traditional methods.
In mechanical tests, AM350 stainless steel generally exhibits an ultimate tensile strength of 140 ksi, yield strength of 115 ksi, and an elongation of 15%. Its fracture toughness is reported as 40MPam1/2, which is slightly lower than that of typical austenitic stainless steels such as 316L, but still comparable to other high-chromium grades such as Type 434.
Its wear resistance properties are also quite desirable, with higher impact values in welded applications compared to those of other austenitic stainless steel grades. Analysis of tribological test results suggest that its wear mechanism is primarily abrasive. Lastly, its corrosion resistance is excellent, with a pitting resistance equivalent of >40, indicating the formation of an oxide layer which prevents further penetration of corrosive agents.
In conclusion, AM350 exhibits a strong combination of attractive properties, such as formability, wear resistance and corrosion resistance, making it an excellent choice for demanding applications. Its high chromium content provides good resistance to chloride-induced attack, making it well-suited for critical components in corrosive environments. Further analysis is required in order to determine the best use-cases for this alloy.
