440F SE (Type 2) is a high carbon martensitic stainless steel that is AOD melted with the addition of selenium for better machinability. These products have been used typically for parts requiring resistance to both corrosion and wear with a hardness up to 58 HRC, where the amount of machining warrants use of a free-machining steel. 440F-Se should be considered for machined parts which require higher hardness values than possible with other free-machining grades. This alloy is heat treatable for an elevated hardness and moderate corrosion resistance. Due to its inherent porosity, it should not be considered for applications involving gas or liquid under pressure. This material is often used for Aircraft Components, Nuclear Industries and Surgical Tools.
