Vessels made of various refractory materials for melting or holding operations; they can be replaced, if necessary. Such crucibles are usually made of refractory clay with graphite additive (graphite melting crucible) or of silicon carbide. They must be resistant to high temperatures without sintering and melting, they must be resistant to cracking in case of significant temperature changes and they must be adequately resistant to liquid metal and slag and different additives.
For melting magnesium alloys, crucibles made of steel are normally used.
Melting pots are subject to considerable wear due to thermal, mechanical and chemical loads. Therefore, they must be monitored, controlled and finally replaced.
The refractory lining of induction furnaces is also referred to as crucible which, in this case however, is firmly mounted as furnace cladding or lining and forms a fixed part of the furnace and must be sintered and replaced after a certain time depending on wear.