Seamless Rolled Ring Forging Process
I. Upsetting
The ring rolling process begins with the upsetting of the starting stock on flat dies at its plastic deformation temperature.
II. Piercing
Piercing involves forcing a punch into the hot upset stock displacing metal radially and leaving a thin web of metal at the bottom.
III. Shearing
A subsequent operation, shearing, removes the thin web producing a completed hole through the stock.
IV. Preforming
This stock, referred to as a blank or preform, is now ready for the ring rolling process.
V. Forming
The doughnut-shaped preform is placed over the mandrel.
As the preform is rotated in the mill, the mandrel begins to apply pressure toward the main roll. At the same time, the axial cones apply pressure toward each other.
As a result of the radial and axial pressure, the ring's OD and ID gradually increase while the thickness and wall section are reduced.
