Forged by 1400t rotary forging machine and then machined tosize. Material: 45#,35CrMo,42CrMo,48CrMoA Specification: OD?270—?420,ID?100—?340? if order or inquiry please mention: *Outer diameter *Inner diameter *Length *Delivery can be rough-machined,heat-treaded or finished-machined. Origin China Material 45#,35CrMo,42CrMo,48CrMoA