Machined from EN24T
This is a Nickel Chromium Molybdenum that combines a good high tensile steel strength with shock resistance, ductility and wear resistance with a tensile strength of 850/1000 N/mm².
The Gears are then further surface-hardened by a Tufftride process to give an enhanced surface wear resistance which gives the finished black surface.
International Steel Specification Comparison (EN24T)
BS 970:1955 EN24T
BS 970:1991 817M40T
German / DIN 34CrNiMo6
French AFNOR 35NCD6
American AISI / SAE 4340
German Werkstoff No. 1.6582
European Standard EN10277-5