Bell Annealing is annealing in a bell
furnace so-named for the bell shape of the outer casing. In bell
annealing, an overhead crane is typically used to load a large batch
of metal, or a charge, onto the furnace base. The furnace base
contains the heat source and provides the heat transfer to the
charge. Next, a stainless steel inner casing is loaded to enclose
the charge. The inner casing maintains the controlled atmosphere and
helps maintain temperature uniformity to the charge. The bell
shaped, carbon steel, outer casing is then loaded to insulate the
interior of the furnace.
The purged furnace heats the charge above its re-crystallization
temperature and held to achieve the desired metallurgical changes.
The outer casing is removed to allow the inner casing to cool. If
rapid or controlled cooling is required, a forced-cooler is placed
over the inner casing. The forced-cooler uses forced air and water
to control the cooling of the inner casing.
LEWCO can design and manufacture a bell furnace tailored to your
application.
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