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EN grade Steel Equivalents and Uses
Even though the British EN (Emergency Number) designation scheme for steel is obsolete it is still widely used. The following table lists the EN grades commonly seen at NHTC and the closest AISI equivalent and the uses for the grade.
EN AISI Uses
EN1A 1213 A mild steel available in round, flat or hexagonal form.
EN3A 1023 A mild steel suitable for general purpose use. Available hot rolled, cold drawn or turned in black round or square, bright round, square, flat or hexagonal.
EN8 1040 A medium strength steel suitable for stressed pins, shafts, studs, keys etc. Available in square, round or flat bar.
EN19 4140 An oil hardenable chromium molybdenum steel used for gears and high strength shafts etc. with good resistance to shock loads. Available as black round or square bar and bright round, square and hexagonal bar.
EN24 4340 An oil hardenable nickel chromium molybdenum steel with high strength and toughness. Used for gears, axles and high strength studs. Available as black round or square bar and bright round, square and hexagonal bar. (small sections can be vacuum hardened).
EN24T 4340 Same as EN24 but pre-hardened to 29-32HRC
EN36 N/A A nickel chromium steel suitable for case hardening. Used for heavy duty gears and shafts. Supplied in black square and round bar bright round bar.
EN41A
(905M31)
N/A A chromium molybdenum steel with aluminium which makes it eminently suitable for nitriding. We have not seen this steel at the NHTC but we feel certain that it would be more suitable for nitriding than some of the steels we are asked to nitride.