Material 

Treatment

Hardness

Application

15,20

carburizing,quenching,tempering

HRC50-60

Z≤25, with impact load

35

normalizing

HBS160-200

Z＞25

45,50,ZG310-570

quenching,tempering

HRC40-45

non servere impact and wearproof

15Cr, 30 Cr

carburizing,quenching,tempering

HRC50-60

Z＞25, high power drive 

40Cr, 35 Si/Mn, 35CrMo

quenching,tempering

HRC40-50

require high strength, and wearproof

A3, A5

Welding tempering

Around HBS140

middle or low speed, medium power big sprocket

Cast iron which is not lower than HT200

quenching,tempering

HBS260-280

Z＞50

Textolite

P＜6kw, high speed, require steady drive, low noise