NITRIDE INCLUSIONS IN HIGH-MANGANESE STEEL.

With a view to further improving the quality of steel castings and enhancing their performance, the authors have explored the possibility of steelmaking under conditions which exclude filmy inclusion formation. Experimental melts were made in 5-tonne basic arc furnaces, by remelting graded internal scrap without final aluminum additions. The steel was tapped in two stages, first into a stoppered distribution ladle and then portion by portion into 300-kg pouring ladles treated with increasing amounts of aluminum additive. Samples were taken from each pouring ladle for chemical analysis, metallographic examination and mechanical testing. Since adopting the new technology, the performance of castings in mining and ore-processing equipment has improved by 30-50%.