Applying of Aluminium Deoxidation in Iron Roll Casting

Abstract

In producing cast iron rolls for use in the hot rolling of billets, the furnace charge materials consist of bought in scrap, foundry returns and pig iron. Normally, to achieve acceptable casting quality, charges contain at least 30% pig iron. To meet increasingly tougher competition, foundries would like to reduce costs by using cheaper raw materials. To use greater proportions of steel scrap in place of the more expensive pig iron. However, castings might suffer from gas related defects such as pores. In general, aluminium is not used to deoxidize cast irons due to concerns that it may cause hydrogen pinholing. This study examines the potential for deoxidation with aluminium in producing iron castings free from gas related defects. The work suggests that only alloyed cast iron (Ni-Hard grade) can be considered for deoxidation because higher tapping temperatures to complete the oxidizing reaction of aluminium. The optimal amount of aluminium was found to be 0.05% by weight of the charge added as a ladle additive just before pouring.