EFFECTS OF VARIATIONS IN MANGANESE ON DIFFERENT GRADES OF IRON.
This chapter presents the results of tests made by the author with a wide range of different grades of iron, having varying percentages of manganese, to give information that will be applicable to nearly all classes of founding. The tests far surpass anything previously presented for covering a broad field, and were originally presented by the author to the American Foundrymen's Association Convention at Buffalo, N. Y., June, 1901. The results shown in Tables 35 and 36 pages 236 and 237, verify some of the properties attributed to manganese and, the writer believes, amplify our knowledge of its effect on cast iron considerably. We shall first outline the methods of physical testing followed in this work.
The breaking strength and deflection given in columns 3 and 4, Table 35, are each the average of about four tests, two of the tests being from i^-inch round bars cast on end, and two from i-inch square bars cast flat, and used for obtaining the contraction and chill. All bars were tested 12 inches between supports.
The contraction tests recorded in column 5, Table 35, were obtained by casting square bars A and B in a frame C, Fig. 52. The contraction was measured by:0314 3:o43£ 2:03 3:04^ 2:03^ 3:o5