DS EN 4635:2009 Aerospace Series - Screws, 100 Degree Countersunk Head, Six Lobes Recess, Short Thread, In Heat Resisting Nickel Base Alloy Ni-Ph2601 (Inconel 718) - Classification: 1270 Mpa (At Ambient Temperature)/650 Degree C Defines the characteristics of screws with 100 degree countersunk head, with six lobe recess, short thread, in heat resisting nickel base alloy NI-PH2601 (Inconel 718), for aerospace applications.