Advancements in Production of Heavy Wear-Resistant Castings

摘要

The advancement in the production techniques of Grinding Ring castings used by thermal power plants for pulverising coal, weighing 5 tonnes to 16 tonnes single-piece has been discussed in this paper in detail. It is difficult to make these castings by conventional hand moulding in mould boxes. Special moulding technique viz; core assembly sweep technique has been developed to make these castings. Wear-resistant materials are hard with carbide in the structure to with-stand the abrasion. The wear-resistant white cast iron is alloyed with Nickel and Chromium, which generates insoluble slag. The gating system has to ensure that slag does not enter the mould. Also due to high solidification contraction, proper risering of the casting has to be designed, to obtain internally sound casting. Heat treatment is equally important to achieve the desired microstructure so that the casting performs best, under severe abrasive conditions.