Graphite crucible is widely used in casting but many customers don’t know how to use it correctly.
It is very significant for a new made graphite crucible to be conditioned before it is used. Using a graphite crucible correctly includes conditioning and storage. The crucible should be put in an oven at 500 degrees Fahrenheit (260 degrees Celsius) for two hours and then allowed to cool slowly in a dry situation. This keeps moisture from the crucible and prevents cracking. Crucibles should be kept away from moisture and should be re-conditioned if they get wet.
A graphite crucible should be cleaned completely when it is done being used. Metal should not be allowed to remain in the crucible to cool. Residual metal can expand and crack the crucible when it is reheated. Crucible tongs should be used that match the shape of the crucible. To prevent cracking, the tongs should hold the crucible without putting pressure on the sides.
Graphite crucibles can be damaged by improper use or handling. They should not be used for metals containing iron, because iron will react directly with the carbon in the crucible and will change the metal composition or destroy the crucible. Solid metals should be loosely packed in a crucible before it is heated. The metals might expand, and a tightly packed crucible can crack or fail. Water or damp metals should never be added to molten metal in a crucible, because that might cause a steam explosion or result in failure of the crucible.