Design of risers by the cooling curve method

The ultimate aim of any foundryman is to produce castings of maximum soundness at minimum cost. The need to provide a feeder to a casting as a means of producing of sound castings is well known. To produce maximum soundness in a casting with minimum feeder volume will, therefore, be the objective of all foundrymen and efforts to devise new and more accurate methods to find out minimum feeder volume will continue. After presenting the details of the cooling curve method for finding the minimum feeder volume and application of this method to grey iron castings, the author has presented experimental results of his laboratory scale trials and critical observations on the use of the cooling curve method to design plain as well as exothermic risers for grey iron castings. (Shri G.N. Rao, Scientist, National Metallurgical Laboratory, Jamshedpur)