Causes of cracks formation in quartzite lining of induction crucible kiln with industrial frequency during iron smelting and events of insight of liquid metal into lining are considered in this article. Demonstrable presentation of this events, which was recognizing during research of causes of anticipated kilt out of its exploitation through a fault lining during its shake-out are considered. The main reasons for the formation of cracks in the lining during its operation, and ways to prevent them are given. The most difficult situations from the point of view of the correct operation of an industrial-frequency induction crucible furnace are described.