The material of the sprocket should have sufficient wear resistance and strength.Generally, better materials are used for small sprockets.Under normal working conditions, 455045Mn steel is used, after quenching and tempering, the tooth surface hardness is 40~50HRC.Under important conditions, use 15Cr20Cr material, surface carburizing quenching and tempering treatment, tooth surface hardness 55~60HRC; or 40Cr35CrMo material, quenching and tempering treatment, tooth surface hardness 40~50HRC.Under simple conditions, 35 steel is normalized and the tooth surface hardness is 160~200HBS; or 1520 steel is surface carburized, quenched and tempered, and the tooth surface hardness is 50~60HRC.