ESSENTIAL RELATIONS TO THIXOGIES, PROCEDURES FOR THE MANUFACTURING OF HALF-FILLED GIESS MATERIAL FOR THIXOGIES, PROCEDURES FOR THIXOGIES, BASIC SUBSTANCES AND PROCEDURES FOR THE HEATING OF BASIC SUBSTANCES

摘要

An Fe-based cast product with 1.8-2.5 wt% C, 1.4-3.0% Si and 0.3-1.3% Mn which is produced by thermally treating an Fe-based cast product made by utilizing a thixocasting process using an Fe-based casting material as a casting material, said Fe-based cast product including a matrix and a large number of groups of massive fine alpha -grains dispersed in the matrix, said Fe-based cast product having a thermally-treated texture where a large number of graphite phases are dispersed in said matrix and each of said groups of fine alpha -grains, and said Fe-based cast product having a free-cutting property such that a ratio B/A of an area rate B of the graphite phases in all said groups of fine alpha -grains to an area rate A of the graphite phases in the entire thermally-treated texture is in a range of B/A 0.138. The thermal treatment is made under the conditions where, when a eutectoid temperature of said as-cast product is Te, the thermally treating temperature T is set in a range of Te T Te + 170 DEG C, and the thermally treating time t is set in a range of 20 minutes t 90 minutes, thereby providing a thermally-treated product with a free-cutting property.