Originally Posted by
RVDT
Really? Quote a model with a stainless steel mast.
you are not talking to the expert here, but, I have references that show both the rotor mast of the AS350 astar and the top of the engine deck are stainless steel (I assume it is forged and stress relieved.. but I am drifting)
edit: a bit more research showsFerrium S53 (AMS 5922, MMPDS) is an ICME-designed, corrosion resistant, ultra-high strength steel for structural aerospace and other applications where 300M (BS S155) and 4340 are typically used, but S53 steel provides: much greater resistance to general corrosion and to stress corrosion cracking (SCC); excellent resistance to fatigue and to corrosion fatigue; and high hardenability. Its resistance to general corrosion is similar to that of 440C stainless steel, but it has much greater fracture toughness. S53 steel is double vacuum melted (i.e., vacuum induction melted and then vacuum arc remelted or "VIM/VAR") for high purity, leading to much greater fatigue strength. Because of its high resistance to corrosion and ultra high strength and toughness combination, S53 steel is being used in demanding landing gear and
helicopter rotor shaft applications without the use of toxic cadmium coatings.