D4D Spocket rim, Oem No. 7K2514/4N4107 The material is 40CR or 50Mnthe surface hardness is HRC 56-62, depth 5-7 mm Sporcket is carefully heat treated to ensure long wear life and stress resistence and precision machined Our spocket for bulldozer are specially designed, engineered and manufactured for high impact applications. Bulldozer spocket are designed for applications that call for the maximum wear resistance.  We use good material to ensure quality and consistency.