How to Use Graphite Crucibles?

Graphite crucibles have slowly developed into an important part of metal forming. They can be as small as a teacup or large enough to hold several tons of molten metal and become a permanent part of the furnace.

The different forms of graphite crucibles have as wide a range of variations as the different size forms. Here are a few ways in which graphite crucibles can be used.

Induction Furnaces

The selection of graphite crucibles for oil-fired and electric furnaces is much easier than for graphite crucibles for induction furnaces. In one type of induction furnace, crucibles are used to melt the charge, while in other types, the induction field passes through them. The crucible must be matched to the operating frequency of the furnace and to the specific application. In low-frequency furnaces, crucibles are made of high silicon and carbide content. In high-frequency furnaces, they are made of clay. Correct matching prevents the crucible from overheating.

Fuel Furnaces

Fuel furnaces powered by natural gas, oil, propane or coke require graphite crucibles capable of withstanding the maximum energy or BTU from the furnace. Furnaces fueled by gas, oil and propane use crucibles designed to withstand the burner flame around the crucible cone to achieve uniform heat distribution.

Removable Crucible Furnaces

Furnace crucibles are "A" shaped, so they can be removed from the furnace with pliers to pour out the molten metal. They can be mounted inside or outside the furnace and allow their contents to be poured out.

Resistance Furnaces

Graphite crucibles for resistance furnaces must be specially designed because electric furnaces heat up much more slowly than oil-fired furnaces. Crucibles must have a high graphite content in the carbon binder to achieve energy savings and high thermal conductivity. They are basin-shaped and located at an equal distance from the heating element.

Tilting the furnace

The graphite crucible for tilting the furnace remains stationary while the furnace is tilted to pour molten metal. Tiltable furnaces can be induction or electric furnaces capable of melting steel, iron, copper, brass, gold, platinum, silver, nickel, palladium and their alloys.

Pit-type furnaces

Pit-type furnaces are located below the floor. The crucible is placed in the furnace and the metal to be melted is placed in it. In the heating chamber, coke is wrapped around the crucible. After the metal is melted, the crucible is removed.

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