抄録
In nodular iron castings, we learned that their properties depend very much on a method of the nodulizing treatment, characteristics of the base metals and the shape of casting. This rasearch has been done experimentally to find the fundamental conditions of its practice in foundry shops. In the first case, the base metals are melted by the cupola, and in the second case by the electric furnace. Mg—Si alloy is used as a nodulizing element. The results of the experiment. 1) Even if the graphite is not nodulized by the treatment, the mechanical properties are much improved. 2) The tensile strength increases with the percentage of the nodulized graphite. 3) Phosphor content in the base metal has much effect on mechanical properties. 4) Silicon content after the treatment defines the microscopic structure. 5) Sulphor is lowered by the treatmentand gradually increases with the time. 6) Thickness of castings has much effect on mechanical properties.
