Zinc is commonly included in ferrous scrap used to charge induction-melting furnaces for foundries, but zinc also affects the refractory lining material, requiring some changes to the sintering procedure — in order to maintain the lining’s effectiveness. For example, it helps to charge the zinc-coated steel scrap early in the melt cycle, allowing more time for the zinc to evaporate out of the melt. An extended melt cycle also may be necessary, to get the zinc concentration down to acceptable levels.
It has been found that using zinc-free material for the sinter heat helps to reduce the amount of zinc penetration into the lining.
Read Daniel Green, Ph.D.’s full report, Understand the Effects of Zinc Penetration on Induction Furnace Linings … and How to Compensate for It