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 (A) This process typically begins
with upsetting of the starting stock on flat dies at its plastic
deformation temperature -- in the case of grade 1020 steel, approximately
2,200 Fahrenheit. The upsetting operation introduces wrought properties to
the starting stock and begins the development of a workpiece preform
configuration that is conductive to subsequent steps.

(B) Piercing -- forcing a punch into the hot
upset stock causing metal to be displaced radially, as shown.

(C) Shearing serves to remove the small
punchout...
(D) producing a completed hole through the stock which
is now ready for the ring rolling operation itself. At this point the
stock is called preform.

(E) The doughnut-shaped preform is slipped over the ID roll,
shown here from an "above" view.
(F) A side view of the ring mill
and preform workpiece. The free-turning ID roll exerts force force against
the OD roll which imparts a rotary action...

(G) resulting in a thinning of the section and
a corresponding increase in the diameter of the ring. Once off the ring
mill, the ring is then ready for secondary operations such as close
tolerance sizing, parting, heat treatment and
test/inspection. |