Raw material：20CrMoM
Internal interface formed by cold forging,two external spline formed by spline rolling in a single process,other feature machined by turning,milling and grinding process
Heat treatment-1：Quenching and tempering to achieve 290 HV30
Heat treatment-2：Induction heat treatment for 2 area to achieve HV400 min.
Tolerance requirements on outer diameter：7 micron
Tolerance requirements on inner diameter  ：13 micron
Laser marking with 2D barcode for traceability