A batch-operated heat-treatment furnace in which products are heated under a movable dome. It is used for heat treatment of sheet and light-section rolled products in a controlled gaseous medium. Bell furnaces are classified according to use (treatment of coils of narrow strip, sheets, rods, and so on).

• o Bell Annealing is a type of annealing that derives its name from the shape of the furnace used during the process.
• o Bell Annealing Heats Batches of metal which are placed on a base assembly, enclosed in inner cover, and covering by furnace body.
• o When the furnace is suspended from the crane it looks like Bell.
• o The base assembly is the source of convection and the main method of heat transfer to charge.