On the Production and Mechanical Properties of Malleable Iron Castings with Spheroidal Graphite. (Studies of Malleable Iron Castings with Spheroidal Graphite (I))

The following results were obtained by adding small amounts of various special substances to molten iron of ordinary malleable iron castings.(1) Malleable iron castings with spheroidal graphite is obtainable.(2) The special substance gives a carbide stabilizing effect to the molten iron. When the special substance is added to the molten iron, the heavy white iron section is obtainable. Because of the high silicon content and spheroidal graphite, the annealing time is shorter and the mechanical properties is better than the ordinary malleable iron castings.(3) The mechanical properties of this iron of the ferritic-type are 42 to 50 kg/mm2 in tensile strength, 17 to 21 percent in elongation and more than 150° in bend. The iron of the pearlitic-type has the properties: tensile strength, 77 to 85 kg/mm2: elongation, 2 to 4.5 percent: Brinell hardness, 250 to 280.