Use this how-to guide to select an optimal crucible given your metalcasting facility operations, applications and desired crucible characteristics. DIDIER FINCK AND DIETER HEUMANNSKAEMPER, MORGAN MOLTEN METAL SYSTEMS
M
etalcasting facility melting depart- ments tend to be unique operations
with specific combinations of furnaces, alloys, work practices, metallurgical treatments, pouring arrangements and end products not likely to be duplicated at any other facility. Choosing a cru- cible that achieves maximum perfor- mance is just as individualized. Te modern crucible is composed
of a heterogeneous, graphite-based composite material relying on its com- position and control of the graphite’s
34 | MODERN CASTING May 2012
structural alignment to achieve the required performance. Crucibles may be as small as a teacup or large enough to hold several tons of metal. Tey may be fixed in place within a furnace structure or designed for removal from the furnace for pouring. Tey are used in fuel-fired, electric resistance and induction furnaces and for transferring molten metal. Tey come with or with- out pouring spouts in a wide variety of traditional and specialized shapes. Crucibles offer many performance
characteristics, as each application presents a unique set of temperature,
chemical and physical parameters that define the technical boundaries of the crucible. Te best approach to selecting the proper crucible is to begin with a detailed assessment of operations and full documentation of all aspects of melting, holding and metal handling processes. Tese include: • Capacity, dimensions and type of furnace.
• Specific alloy or range of alloys melted.
• Melting and/or holding tempera- tures maintained.
• Temperature change rates experienced;
Matching
the Crucible to the Application
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