... 75%-90%(Confirmed by the speed and material).3,Abrasion plate with material in.4,Two ... chain plate:40Cr . 2,Pin shaft :20CrMnMo . 3,Sleeve :20CrMo . 4,Roller:20CrMo.Hardening and tempering ... abrasion to chains and the lengthening of the pitch. 3,External chain plate is punched into bending plate ... 20CrMo forging steel.high strength and reamed bolt.3,Technical figure, low speed with12 tooth,High speed ...